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<journal-meta>
<journal-id journal-id-type="nlm-ta">PLoS ONE</journal-id>
<journal-id journal-id-type="publisher-id">plos</journal-id>
<journal-id journal-id-type="pmc">plosone</journal-id>
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<journal-title>PLOS ONE</journal-title>
</journal-title-group>
<issn pub-type="epub">1932-6203</issn>
<publisher>
<publisher-name>Public Library of Science</publisher-name>
<publisher-loc>San Francisco, CA USA</publisher-loc>
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<article-meta>
<article-id pub-id-type="doi">10.1371/journal.pone.0137477</article-id>
<article-id pub-id-type="publisher-id">PONE-D-15-19974</article-id>
<article-categories>
<subj-group subj-group-type="heading">
<subject>Research Article</subject>
</subj-group>
</article-categories>
<title-group>
<article-title>The Influence of Intersections on Fuel Consumption in Urban Arterial Road Traffic: A Single Vehicle Test in Harbin, China</article-title>
<alt-title alt-title-type="running-head">The Influence of Intersections on Fuel Consumption</alt-title>
</title-group>
<contrib-group>
<contrib contrib-type="author" xlink:type="simple">
<name name-style="western">
<surname>Wu</surname>
<given-names>Lina</given-names>
</name>
<xref rid="aff001" ref-type="aff"><sup>1</sup></xref>
<xref rid="aff002" ref-type="aff"><sup>2</sup></xref>
</contrib>
<contrib contrib-type="author" corresp="yes" xlink:type="simple">
<name name-style="western">
<surname>Ci</surname>
<given-names>Yusheng</given-names>
</name>
<xref rid="aff003" ref-type="aff"><sup>3</sup></xref>
<xref rid="cor001" ref-type="corresp">*</xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple">
<name name-style="western">
<surname>Chu</surname>
<given-names>Jiangwei</given-names>
</name>
<xref rid="aff002" ref-type="aff"><sup>2</sup></xref>
</contrib>
<contrib contrib-type="author" xlink:type="simple">
<name name-style="western">
<surname>Zhang</surname>
<given-names>Hongsheng</given-names>
</name>
<xref rid="aff004" ref-type="aff"><sup>4</sup></xref>
</contrib>
</contrib-group>
<aff id="aff001"><label>1</label> <addr-line>College of Automobile and Traffic Engineering, Heilongjiang Institute of Technology, Harbin, Heilongjiang, China</addr-line></aff>
<aff id="aff002"><label>2</label> <addr-line>College of Traffic, Northeast Forestry University, Harbin, Heilongjiang, China</addr-line></aff>
<aff id="aff003"><label>3</label> <addr-line>School of Transportation Science and Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, China</addr-line></aff>
<aff id="aff004"><label>4</label> <addr-line>School of Mechatronics Engineering, Harbin Institute of Technology, Harbin, Heilongjiang, China</addr-line></aff>
<contrib-group>
<contrib contrib-type="editor" xlink:type="simple">
<name name-style="western">
<surname>Hu</surname>
<given-names>Xiaosong</given-names>
</name>
<role>Editor</role>
<xref ref-type="aff" rid="edit1"/>
</contrib>
</contrib-group>
<aff id="edit1"><addr-line>University of California Berkeley, UNITED STATES</addr-line></aff>
<author-notes>
<fn fn-type="conflict" id="coi001">
<p>The authors have declared that no competing interests exist.</p>
</fn>
<fn fn-type="con" id="contrib001">
<p>Conceived and designed the experiments: L-NW Y-SC J-WC. Performed the experiments: L-NW Y-SC. Analyzed the data: L-NW Y-SC. Contributed reagents/materials/analysis tools: L-NW Y-SC H-SZ. Wrote the paper: L-NW Y-SC.</p>
</fn>
<corresp id="cor001">* E-mail: <email xlink:type="simple">ciyusheng1999@126.com</email></corresp>
</author-notes>
<pub-date pub-type="epub">
<day>14</day>
<month>9</month>
<year>2015</year>
</pub-date>
<pub-date pub-type="collection">
<year>2015</year>
</pub-date>
<volume>10</volume>
<issue>9</issue>
<elocation-id>e0137477</elocation-id>
<history>
<date date-type="received">
<day>8</day>
<month>5</month>
<year>2015</year>
</date>
<date date-type="accepted">
<day>17</day>
<month>8</month>
<year>2015</year>
</date>
</history>
<permissions>
<copyright-year>2015</copyright-year>
<copyright-holder>Wu et al</copyright-holder>
<license xlink:href="http://creativecommons.org/licenses/by/4.0/" xlink:type="simple">
<license-p>This is an open access article distributed under the terms of the <ext-link ext-link-type="uri" xlink:href="http://creativecommons.org/licenses/by/4.0/" xlink:type="simple">Creative Commons Attribution License</ext-link>, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited</license-p>
</license>
</permissions>
<self-uri content-type="pdf" xlink:href="info:doi/10.1371/journal.pone.0137477" xlink:type="simple"/>
<abstract>
<p>The calculating method for fuel consumption (<italic>FC</italic>) was put forward and calibrated and the characteristics of the fuel consumption on intersections were analyzed based on 18 groups of vehicular operating data which were acquired from the test experiment of a single vehicle along the urban arterial roads in Harbin, China. The results obtained show that 50.36% of the fuel consumption for the test vehicle was used at the area of intersections compared with 28.9% of the influencing distance and 68.5% of the running time; and 78.4% of them was burnt at the stages of acceleration and idling. Meanwhile, the type (c) of the vehicular operating status was illustrated to be the worst way of reducing fuel consumption, the causes were analyzed and four improvement strategies were put forward.</p>
</abstract>
<funding-group>
<funding-statement>This work was financially supported by the Scientific Research Fund of Heilongjiang Provincial Education Department of China (No. 12541650).</funding-statement>
</funding-group>
<counts>
<fig-count count="0"/>
<table-count count="0"/>
<page-count count="10"/>
</counts>
<custom-meta-group>
<custom-meta id="data-availability" xlink:type="simple">
<meta-name>Data Availability</meta-name>
<meta-value>All relevant data are within the paper and its Supporting Information files.</meta-value>
</custom-meta>
</custom-meta-group>
</article-meta>
</front>
<body>
<sec id="sec001" sec-type="intro">
<title>Introduction</title>
<p>Statistically, one-third of the gasoline was exhausted by autos worldwide each year; and energy supply had become one of huge challenges for human beings. Consequently, 3 main fuel consumption reduction technologies were put forward and implemented from the aspects of vehicles, driving behaviors and traffic management and control respectively. Above all, advanced engine technologies, which were usually improved by auto makers and researchers, were gradually applied including hybrid electric engine, and turbocharger technology. For instance, hybrid electric vehicles (HEVs) or plug-in hybrid electric vehicles (PHEVs) were proved to be successful to reduce the fuel consumption; many relative strategies and methods were proposed to save the HEVs fuel consumption. Hu <italic>et al</italic>. and Yang <italic>et al</italic>. addressed the electrochemical energy buffers and robust coordinated control applied for the HEVs separately and the results showed that the proposed strategy could improve the fuel economy [<xref rid="pone.0137477.ref001" ref-type="bibr">1</xref>,<xref rid="pone.0137477.ref002" ref-type="bibr">2</xref>]. Hu <italic>et al</italic>. and Li <italic>et al</italic>. discussed the two optimization-based and dynamic programming-based global optimal energy management strategies for the plug-in hybrid electric bus (PHEBs) [<xref rid="pone.0137477.ref003" ref-type="bibr">3</xref>,<xref rid="pone.0137477.ref004" ref-type="bibr">4</xref>]; Sun <italic>et al</italic>. developed a PHEVs energy management algorithm to achieve enhanced fuel economy under different traffic flow information conditions [<xref rid="pone.0137477.ref005" ref-type="bibr">5</xref>]. Zheng <italic>et al</italic>. analyzed the effect of battery temperature on fuel consumption of fuel cell hybrid vehicles (FCHVs) [<xref rid="pone.0137477.ref006" ref-type="bibr">6</xref>]; Hu <italic>et al</italic>. discussed the optimal dimensioning or longevity-conscious dimensioning and power management for the fuel cell hybrid buses (FCHBs) with the method of convex programming and the findings showed that they are optimal and efficient [<xref rid="pone.0137477.ref007" ref-type="bibr">7</xref>,<xref rid="pone.0137477.ref008" ref-type="bibr">8</xref>]. Meanwhile, stop-start technology (STT) can save about 5~15% fuel consumption [<xref rid="pone.0137477.ref009" ref-type="bibr">9</xref>]; and the turbocharger technology can also reduce fuel consumption for the vehicles and be used widely.</p>
<p>Then, eco-driving is encouraged and can reduce fuel consumption accordingly. Of course, some assistance system should be used. Staubach <italic>et al</italic>. evaluated an eco-driving support system utilizing a driving simulator; the system can communicate with traffic lights and gives recommendations to the drivers concerning acceleration/deceleration behaviors [<xref rid="pone.0137477.ref010" ref-type="bibr">10</xref>]. Lai discussed the effects of eco-driving on fuel efficiency with the before-after data with a reward system; and the results indicated that around 10% of the fuel consumption can be saved with the system [<xref rid="pone.0137477.ref011" ref-type="bibr">11</xref>]. McIlroy <italic>et al</italic>. provided a decision ladder analysis of eco-driving and a discussion of the resultant models for the skills, rules and knowledge taxonomy [<xref rid="pone.0137477.ref012" ref-type="bibr">12</xref>].</p>
<p>Finally, the strategies and methods of traffic management and control can be implemented to economize fuel consumption. This is the focus of this article. A number of earlier research findings revealed that the fuel consumption per unit distance can be approximately described as a linear function of the average speed and stop frequency [<xref rid="pone.0137477.ref013" ref-type="bibr">13</xref>,<xref rid="pone.0137477.ref014" ref-type="bibr">14</xref>]. Rakha <italic>et al</italic>. indicated the vehicle fuel consumption rates increased considerably as a stop, especially at high cruising speeds. Meanwhile, the levels of average speed and acceleration were also of significant importance [<xref rid="pone.0137477.ref015" ref-type="bibr">15</xref>]. Ahn <italic>et al</italic>. built up microscopic fuel consumption and emission models with the input variables of instantaneous vehicle speed and acceleration levels and developed using the Oak Ridge National Laboratory (ORNL) data [<xref rid="pone.0137477.ref016" ref-type="bibr">16</xref>].</p>
<p>However, the fuel consumption on intersection area is completely different with common urban road segments. Here are 3 primary kinds of advanced control strategies we can conclude. For a start, traffic engineers or researchers put forward relative methods to analyze or reduce the fuel consumption on intersection involving vehicle running state analysis, traffic design, traffic management and control and traffic flow investigation. Luo set up vehicle fuel consumption models based on vehicle running state data by simulating at intersections. It shows that the fuel consumption is mainly affected by travel speed, stop rate and delay [<xref rid="pone.0137477.ref017" ref-type="bibr">17</xref>]. Zhang <italic>et al</italic>. and Xiang <italic>et al</italic>. discussed the factors affecting vehicle fuel consumption, analyzed the vehicle running characteristics and proposed fuel consumption models at pre-time signalized intersections [<xref rid="pone.0137477.ref018" ref-type="bibr">18</xref>,<xref rid="pone.0137477.ref019" ref-type="bibr">19</xref>]. Feng <italic>et al</italic>. established a statistical model for evaluation on fuel economy of urban intersections considering saturation and splits and revealed the relationship among the traffic flow state, signal control parameters and the fuel economy [<xref rid="pone.0137477.ref020" ref-type="bibr">20</xref>]. Moreover, connected vehicles are being used to reduce fuel consumption, such as vehicle to infrastructure (V2I), vehicle to vehicle (V2V) and etc. Adaptive traffic lights using car-to-car communication is a manner of great of importance. Li <italic>et al</italic>. put forward the concept of safety driving patterns, analyzed the group communication strategy at the blind crossings and finally conducted simulation studies [<xref rid="pone.0137477.ref021" ref-type="bibr">21</xref>]. Asadi <italic>et al</italic>. and Mahler <italic>et al</italic>. presented the use of upcoming traffic signal information and a predictive optimal velocity-planning algorithm to reduce idle time and fuel consumption for the vehicles at the stop lines [<xref rid="pone.0137477.ref022" ref-type="bibr">22</xref>,<xref rid="pone.0137477.ref023" ref-type="bibr">23</xref>]; Bie <italic>et al</italic>. proposed a travel time prediction model on be basis of global positioning system (GPS) data [<xref rid="pone.0137477.ref024" ref-type="bibr">24</xref>]. Finally, eco-driving has gained interest worldwide. Xia <italic>et al</italic>. developed a dynamic eco-driving velocity planning method and the corresponding algorithm for the signalized arterial corridors and it approved that it can save around 10–15% of the fuel consumption [<xref rid="pone.0137477.ref025" ref-type="bibr">25</xref>]; and Zhang <italic>et al</italic>. proposed the eco-driving strategies and the model with good performance on energy consumption reduction [<xref rid="pone.0137477.ref026" ref-type="bibr">26</xref>].</p>
<p>Unfortunately, little information has focus on the vehicle fuel consumption influenced by the existence of the intersection in urban arterial road directly. It has been approved that the impact of the intersection on the vehicular operating is significant in the urban arterial road. How does it affect the fuel consumption of the vehicle exactly? This paper tries to use the detailed on-site test to illustrate this point. Therefore, the core interest of this paper lies in problems concerning the composing, calculating method and characteristics of the fuel consumption for the intersections of urban arterial roads in Harbin, China.</p>
<p>The paper consists of following sections: Section 2 shows the data acquisition. Section 3 builds fuel consumption calculation model and its calibration; Section 4 analyses the characteristics of fuel consumption on intersections; Section 5 is the discussion; and the conclusions are drawn in Section 6.</p>
</sec>
<sec id="sec002">
<title>Data Acquisition</title>
<sec id="sec003">
<title>Test route and test vehicle</title>
<sec id="sec004">
<title>Test route</title>
<p>Origin: 2 Huashan North Road, Nangang District, Harbin, China.</p>
<p>Destination: 228 Dongzhi Road, Daowai District, Harbin, China.</p>
<p>Road composing: 4 arterial roads including Huashan North Road, Xianfeng Road, Hongqi Avenue and Dongzhi Road.</p>
<p>Intersection types and composition: 10 intersections including 9 signalized intersections and a 3-way stop intersection.</p>
<p>Route distance: the whole route is 4370 meters long.</p>
<p>Pavement condition: the roadway pavements of the entire route are paved with asphalt concrete within 5 years and dry, and there are no significant ruts and other distresses.</p>
<p>The test route is designed and showed (<xref rid="pone.0137477.s002" ref-type="supplementary-material">S1 Fig</xref>).</p>
</sec>
<sec id="sec005">
<title>Test vehicle</title>
<p>A gasoline car of 2003 Jetta CIF with 138,000 km and a 2011 Skoda Octavia with 72,490 km were used as the test vehicles and were both timely maintained. Meanwhile, there was a driver and a passenger in the car without any other loading. The relative technical parameters of the test vehicles are listed (<xref rid="pone.0137477.s011" ref-type="supplementary-material">S1 Table</xref>).</p>
</sec>
</sec>
<sec id="sec006">
<title><italic>FC</italic> test system</title>
<p>A software named VCDS ZHS 12.12.0 was designed by Ross-Tech LLC, which is a diagnostic and test system for VW-Audi group cars. Here, it was installed at the computer and connected with the test car using the given cable correctly before testing. The operation interface and the cable of the test system are showed (<xref rid="pone.0137477.s003" ref-type="supplementary-material">S2 Fig</xref>).</p>
<p>From the test system, the data of engine velocity, engine load, injection timing, recording time and etc. were recorded as a Microsoft excel file.</p>
</sec>
<sec id="sec007">
<title>Sampling</title>
<p>Along the test route, the experiments were implemented during the non-peak hours, morning and evening rush hours on October 11<sup>th</sup>, 13<sup>th</sup>, 14<sup>th</sup>, 16<sup>th</sup>, 21<sup>st</sup>, 22<sup>nd</sup>, and 27<sup>th</sup>, 2014 and July 1<sup>st</sup>, and 2<sup>nd</sup>, 2015. Consequently, 18 groups of experimental data were acquired by the test system.</p>
</sec>
</sec>
<sec id="sec008">
<title><italic>FC</italic> Calculation</title>
<sec id="sec009">
<title><italic>FC</italic> composing</title>
<p><italic>FC</italic> of the test vehicle is composed of the following four parts, which are the acceleration (<italic>FC</italic><sub><italic>a</italic></sub>), the deceleration <italic>FC</italic> (<italic>FC</italic><sub><italic>d</italic></sub>), the idling <italic>FC</italic> (<italic>FC</italic><sub><italic>i</italic></sub>) and the uniform velocity travelling <italic>FC</italic> (<italic>FC</italic><sub><italic>u</italic></sub>).
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<mml:mrow><mml:mi>F</mml:mi><mml:msub><mml:mi>C</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mstyle displaystyle="true"><mml:munderover><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>i</mml:mi></mml:msub></mml:mrow></mml:munderover><mml:mrow><mml:mstyle displaystyle="true"><mml:mrow><mml:msubsup><mml:mo>∫</mml:mo><mml:mn>0</mml:mn><mml:mi>t</mml:mi></mml:msubsup><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:msub><mml:mi>f</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mi>d</mml:mi><mml:mi>t</mml:mi><mml:mo>=</mml:mo></mml:mrow></mml:mrow></mml:mstyle><mml:mstyle displaystyle="true"><mml:munderover><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>i</mml:mi></mml:msub></mml:mrow></mml:munderover><mml:mrow><mml:msub><mml:mi>f</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mstyle displaystyle="true"><mml:mrow><mml:msubsup><mml:mo>∫</mml:mo><mml:mn>0</mml:mn><mml:mi>t</mml:mi></mml:msubsup><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mi>d</mml:mi><mml:mi>t</mml:mi></mml:mrow></mml:mrow></mml:mstyle></mml:mrow></mml:mstyle></mml:mrow></mml:mstyle><mml:mo>=</mml:mo><mml:msub><mml:mi>n</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:msub><mml:mi>t</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>f</mml:mi><mml:mi>i</mml:mi></mml:msub></mml:mrow>
</mml:math>
</alternatives>
<label>(4)</label>
</disp-formula>
<disp-formula id="pone.0137477.e005">
<alternatives>
<graphic id="pone.0137477.e005g" position="anchor" mimetype="image" xlink:href="info:doi/10.1371/journal.pone.0137477.e005" xlink:type="simple"/>
<mml:math display="block" id="M5" overflow="scroll">
<mml:mrow><mml:mi>F</mml:mi><mml:msub><mml:mi>C</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mstyle displaystyle="true"><mml:munderover><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>u</mml:mi></mml:msub></mml:mrow></mml:munderover><mml:mrow><mml:mstyle displaystyle="true"><mml:mrow><mml:msubsup><mml:mo>∫</mml:mo><mml:mn>0</mml:mn><mml:mi>t</mml:mi></mml:msubsup><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:msub><mml:mi>f</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:mi>d</mml:mi><mml:mi>t</mml:mi><mml:mo>=</mml:mo></mml:mrow></mml:mrow></mml:mstyle><mml:mstyle displaystyle="true"><mml:munderover><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>u</mml:mi></mml:msub></mml:mrow></mml:munderover><mml:mrow><mml:msub><mml:mi>f</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:mstyle displaystyle="true"><mml:mrow><mml:msubsup><mml:mo>∫</mml:mo><mml:mn>0</mml:mn><mml:mi>t</mml:mi></mml:msubsup><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:mi>d</mml:mi><mml:mi>t</mml:mi></mml:mrow></mml:mrow></mml:mstyle></mml:mrow></mml:mstyle></mml:mrow></mml:mstyle><mml:mo>=</mml:mo><mml:msub><mml:mi>n</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:msub><mml:mi>t</mml:mi><mml:mn>0</mml:mn></mml:msub><mml:msub><mml:mi>f</mml:mi><mml:mi>u</mml:mi></mml:msub></mml:mrow>
</mml:math>
</alternatives>
<label>(5)</label>
</disp-formula>
Where, <italic>t</italic><sub><italic>a</italic></sub>, <italic>t</italic><sub><italic>d</italic></sub>, <italic>t</italic><sub><italic>i</italic></sub> and <italic>t</italic><sub><italic>u</italic></sub> are the average acceleration time, the average deceleration time, the average idling time and the uniform velocity travelling time respectively (s); <italic>t</italic> is the time variable (s); <italic>t</italic><sub>0</sub> is the record time interval (s); <italic>f</italic><sub><italic>a</italic></sub>, <italic>f</italic><sub><italic>d</italic></sub>, <italic>f</italic><sub><italic>i</italic></sub> and <italic>f</italic><sub><italic>u</italic></sub> are the corresponding average <italic>FC</italic> rates (<italic>FCR</italic>s) severally (ml/s); and <italic>n</italic><sub><italic>a</italic></sub>, <italic>n</italic><sub><italic>d</italic></sub>, <italic>n</italic><sub><italic>i</italic></sub> and <italic>n</italic><sub><italic>u</italic></sub> are the recorded segment counts.</p>
</sec>
<sec id="sec010">
<title><italic>FCR</italic>s calibration</title>
<p>From above analysis, <italic>FCR</italic>s are the decisive factors to computing <italic>FC</italic>. <italic>FCR</italic>s calibration hereby was done as follows.</p>
<p>First, the fuel injection quantity for the <italic>i</italic><sup>th</sup> time interval is computed as <xref rid="pone.0137477.e006" ref-type="disp-formula">eq (6)</xref>.
<disp-formula id="pone.0137477.e006">
<alternatives>
<graphic id="pone.0137477.e006g" position="anchor" mimetype="image" xlink:href="info:doi/10.1371/journal.pone.0137477.e006" xlink:type="simple"/>
<mml:math display="block" id="M6" overflow="scroll">
<mml:mrow><mml:msub><mml:mi>q</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:mrow><mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>e</mml:mi></mml:msub></mml:mrow></mml:mfrac><mml:mo>×</mml:mo><mml:mo stretchy="false">(</mml:mo><mml:mfrac><mml:mrow><mml:msub><mml:mi>τ</mml:mi><mml:mrow><mml:mi>i</mml:mi><mml:mo>−</mml:mo><mml:mn>1</mml:mn></mml:mrow></mml:msub><mml:mo>+</mml:mo><mml:msub><mml:mi>τ</mml:mi><mml:mi>i</mml:mi></mml:msub></mml:mrow><mml:mn>2</mml:mn></mml:mfrac><mml:mo stretchy="false">)</mml:mo><mml:mo>×</mml:mo><mml:mi>C</mml:mi><mml:mo>×</mml:mo><mml:mi>K</mml:mi><mml:mo>×</mml:mo><mml:mfrac><mml:mn>1</mml:mn><mml:mi>d</mml:mi></mml:mfrac></mml:mrow>
</mml:math>
</alternatives>
<label>(6)</label>
</disp-formula>
Where, <italic>t</italic><sub><italic>e</italic></sub> is calculated as <xref rid="pone.0137477.e007" ref-type="disp-formula">eq (7)</xref>.
<disp-formula id="pone.0137477.e007">
<alternatives>
<graphic id="pone.0137477.e007g" position="anchor" mimetype="image" xlink:href="info:doi/10.1371/journal.pone.0137477.e007" xlink:type="simple"/>
<mml:math display="block" id="M7" overflow="scroll">
<mml:mrow><mml:msub><mml:mi>t</mml:mi><mml:mi>e</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mfrac><mml:mrow><mml:mn>2</mml:mn><mml:mo>×</mml:mo><mml:mn>60</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>e</mml:mi></mml:msub></mml:mrow></mml:mfrac></mml:mrow>
</mml:math>
</alternatives>
<label>(7)</label>
</disp-formula>
Where, <italic>q</italic><sub><italic>i</italic></sub> is the fuel injection quantity for the <italic>i</italic><sup>th</sup> time interval (ml); <italic>τ</italic><sub><italic>i</italic></sub> is the injection pulse width for the <italic>i</italic><sup>th</sup> record (ms); <italic>C</italic> is the number of cylinders; <italic>K</italic> is the calibrated parameter of the fuel injection quantity, 0.003 g/s; <italic>t</italic><sub><italic>e</italic></sub> is the injection time interval (s); <italic>n</italic><sub><italic>e</italic></sub> is the engine velocity (r/min); and <italic>d</italic> is the density of the used gasoline (g/ml).</p>
<p>Second, <italic>FCR</italic>s are computed as follows.
<disp-formula id="pone.0137477.e008">
<alternatives>
<graphic id="pone.0137477.e008g" position="anchor" mimetype="image" xlink:href="info:doi/10.1371/journal.pone.0137477.e008" xlink:type="simple"/>
<mml:math display="block" id="M8" overflow="scroll">
<mml:mrow><mml:msub><mml:mi>f</mml:mi><mml:mi>j</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mstyle displaystyle="true"><mml:munderover><mml:mo>∑</mml:mo><mml:mrow><mml:mi>i</mml:mi><mml:mo>=</mml:mo><mml:mn>1</mml:mn></mml:mrow><mml:mrow><mml:msub><mml:mi>n</mml:mi><mml:mi>j</mml:mi></mml:msub></mml:mrow></mml:munderover><mml:mrow><mml:msub><mml:mi>q</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mo>/</mml:mo><mml:msub><mml:mi>t</mml:mi><mml:mn>0</mml:mn></mml:msub></mml:mrow></mml:mstyle></mml:mrow>
</mml:math>
</alternatives>
<label>(8)</label>
</disp-formula>
Where, the values of <italic>j</italic> are <italic>a</italic>, <italic>d</italic>, <italic>i</italic>, and <italic>u</italic>.</p>
<p>According to the collected data, average <italic>FCR</italic>s were calibrated (<xref rid="pone.0137477.s012" ref-type="supplementary-material">S2 Table</xref>).</p>
<p>The <italic>FCR</italic>s calibration results for the test vehicle shows that: <italic>f</italic><sub>a</sub> is the highest and it’s twice more of <italic>f</italic><sub>u</sub> and four times more of <italic>f</italic><sub>d</sub> and <italic>f</italic><sub>i</sub>; <italic>f</italic><sub>i</sub> is the lowest and with little gap of <italic>f</italic><sub>d</sub>.</p>
</sec>
<sec id="sec011">
<title><italic>FC</italic> test results</title>
<p>According to the above equations, the real <italic>FC</italic>s for the test vehicle along the test route was calculated based on the collected data (<xref rid="pone.0137477.s013" ref-type="supplementary-material">S3 Table</xref>).</p>
<p>The average <italic>FC</italic> of the test vehicle for the test route is 521.11 ml and the conversion of <italic>FC</italic> per hundred kilometers is 11.9 l/100 km (<xref rid="pone.0137477.s013" ref-type="supplementary-material">S3 Table</xref>).</p>
</sec>
</sec>
<sec id="sec012">
<title>Characteristics of <italic>FC</italic>s on Intersections</title>
<sec id="sec013">
<title>Intersection influencing distance</title>
<p>The intersection influencing distance (IID) is defined as the area range that the vehicle operation is influenced by the existence of the intersection, which consists of two components, the former is the distance between the stop lines of the approach and exit of the intersection along the test route direction, it’s a constant; and the latter is the dilemma zone or the distance between the stop line of the approach and the location of the first stop in the intersection area, it’s a variable.</p>
<p>From the on-site measurement, the first part of the IIDs is 394 meters. However, the second part of the IIDs is varied from 658 meters to 1,200 meters and the average distance is 868 meters. Accordingly, the average is 1,262 meters occupying 28.9% of the whole distance of the test route.</p>
</sec>
<sec id="sec014">
<title>Intersection operation time</title>
<p>The intersection operation time (IOT) is defined as the time duration of the test vehicle travelling during IID. The intersection operation time varies from 392 seconds to 1051 seconds and the average value is 576 seconds accounting for 68.5% of the total test time.</p>
<p>Here, a space-time diagram of the test vehicle from the collected data is showed (<xref rid="pone.0137477.s004" ref-type="supplementary-material">S3 Fig</xref>).</p>
<p>In this space-time diagram of the test route, the main part of test time is made up of IOTs. Furthermore, key intersections can be identified as influencing the operation time and <italic>FC</italic>.</p>
</sec>
<sec id="sec015">
<title>Characteristics of <italic>FC</italic>s on intersections</title>
<p>From the data collected by the test system, <italic>FC</italic>s on intersections can be computed (<xref rid="pone.0137477.s014" ref-type="supplementary-material">S4 Table</xref>).</p>
<p>From the above statistical data, several findings can be discovered as the result of analysis.</p>
<p>For one thing, <italic>FC</italic>s on intersections vary from 190.41 ml to 370.25 ml and the average value is 262.43 ml; it will be much clearer in this way, the percentages of the <italic>FC</italic>s on intersections in <italic>FC</italic>s are from 42.35% to 59.93% and the average percentage is 50.36%, and it means that more than half of the <italic>FC</italic> was used at the area of intersections compared with 28.9% of the IIDs.</p>
<p>For the other, the average <italic>FC</italic><sub>a</sub> is 109.05 ml accounting for 41.6% of the average <italic>FC</italic> on intersections and which is the most important part; the average <italic>FC</italic><sub>i</sub> is 96.47 ml accounting for 36.8% of the average <italic>FCs</italic> on intersections; the average <italic>FC</italic><sub>u</sub> is 28.05 ml accounting for 10.7% of the average <italic>FCs</italic> on intersections and which is the smallest portion. In other words, 78.4% of the <italic>FCs</italic> on intersections was used at the stages of acceleration and idling.</p>
<p>Meanwhile, different intersection <italic>FC</italic>s are computed and listed (<xref rid="pone.0137477.s015" ref-type="supplementary-material">S5 Table</xref>).</p>
<p>According to the data showed (<xref rid="pone.0137477.s014" ref-type="supplementary-material">S4 Table</xref>), <italic>FC</italic> for the No. 6 intersection is 65.13 ml and occupies 24.82% of the <italic>FC</italic> for all intersections and 12.50% of the <italic>FC</italic> for the test route; <italic>FC</italic> for the No. 3 intersection is the second place; and <italic>FC</italic> for the No. 2 intersection is the last one among the all signal control intersections. However, the detailed causes for the high <italic>FC</italic> for the specific intersection will be discussed following.</p>
</sec>
</sec>
<sec id="sec016">
<title>Discussions</title>
<sec id="sec017">
<title>Vehicular operating status analysis at an intersection</title>
<sec id="sec018">
<title>Theoretical analysis</title>
<p>Commonly, the vehicular operating status (VOS) at an intersection can be reduced as three typical types (<xref rid="pone.0137477.s005" ref-type="supplementary-material">S4 Fig</xref>).</p>
<p>For type (a), the vehicle gradually decelerates to stop behind the stop line or queue behind other vehicles when it faces the red light or the green light but cannot deal with all queuing vehicles of the approach. In general, the vehicle will have a process of deceleration-stop-acceleration to pass through the intersection.</p>
<p>For type (b), the vehicle passes the intersection with a uniform velocity approximately or with a process of slight deceleration-acceleration but without stop. This is one of the objectives of the signal control for all vehicles through the intersection and is favorable for saving <italic>FC</italic>.</p>
<p>For type (c), the vehicle is unable to pass the intersection during the period of one signal cycle. So, the vehicle will suffer from several cycles of deceleration-stop-acceleration and the VOS is the most unstable as well. As a matter of course, it’s the worst control strategy and the most unfavorable for saving <italic>FC</italic>.</p>
</sec>
<sec id="sec019">
<title>Experimental data analysis</title>
<p>According to data deduction, the space-velocity diagram for the test vehicle at a specific intersection can be drawn and showed following. Here, a local adjustment is done, but all roads lead to Rome; the distance is used instead of the time for horizontal axis because of more clearness for showing the vehicular operating status on different locations of the intersection.</p>
<p>It shows the space-velocity diagram of the test vehicle at the No. 2 intersection (<xref rid="pone.0137477.s006" ref-type="supplementary-material">S5 Fig</xref>). The test vehicle passes this intersection as the type (b) of the VOS for fourteen times, three times as the type (a) and once as the type (c). This is a relatively ideal one of the VOS at the intersection and beneficial to saving <italic>FC</italic>.</p>
<p>It shows the space-velocity diagram of the test vehicle at the No. 5 intersection (<xref rid="pone.0137477.s007" ref-type="supplementary-material">S6 Fig</xref>). It shows that the test vehicle passes the intersection as the type (a) of the VOS mainly, and it’s not so bad for saving <italic>FC</italic>.</p>
<p>It shows the space-velocity diagram of the test vehicle at the No. 6 intersection (<xref rid="pone.0137477.s008" ref-type="supplementary-material">S7 Fig</xref>). It indicates that the test vehicle passes the intersections as the type (c) of the VOS mainly, and it goes against saving <italic>FC</italic>.</p>
</sec>
</sec>
<sec id="sec020">
<title>Causes and improvement strategies of the high <italic>FC</italic> for a specific intersection</title>
<sec id="sec021">
<title>Causes analysis</title>
<p>Causes of the high <italic>FC</italic> for a specific intersection are basically longer idling time, acceleration time and higher stop frequency. These three factors determine the <italic>FC</italic> for the test vehicle on a specific intersection chiefly, and it can be significantly showed (<xref rid="pone.0137477.s016" ref-type="supplementary-material">S6 Table</xref>).</p>
<p>As for the No. 6 intersection, there are 2 left-turn pocket lanes, 4 through lanes and 1 right-turn lane at the test route approach and 5 lanes at the exit; there are 2 left-turn pocket lanes, 2 through lanes and 1 right-turn lane at the approach and 3 lanes at test route exit. This intersection is very big actually, and the traffic demand is huge.
<disp-formula id="pone.0137477.e009">
<alternatives>
<graphic id="pone.0137477.e009g" position="anchor" mimetype="image" xlink:href="info:doi/10.1371/journal.pone.0137477.e009" xlink:type="simple"/>
<mml:math display="block" id="M9" overflow="scroll">
<mml:mrow><mml:mi>F</mml:mi><mml:msub><mml:mi>C</mml:mi><mml:mi>c</mml:mi></mml:msub><mml:mo>=</mml:mo><mml:mn>10.58</mml:mn><mml:msub><mml:mi>S</mml:mi><mml:mi>f</mml:mi></mml:msub><mml:mo>+</mml:mo><mml:mn>0.1</mml:mn><mml:msub><mml:mi>t</mml:mi><mml:mi>i</mml:mi></mml:msub><mml:mo>+</mml:mo><mml:mn>21.66</mml:mn><mml:mo stretchy="false">(</mml:mo><mml:msup><mml:mi>R</mml:mi><mml:mn>2</mml:mn></mml:msup><mml:mo>=</mml:mo><mml:mn>0.99</mml:mn><mml:mo stretchy="false">)</mml:mo></mml:mrow>
</mml:math>
</alternatives>
<label>(9)</label>
</disp-formula>
Where, <italic>FC</italic><sub><italic>c</italic></sub> is the <italic>FC</italic> on an intersection; and <italic>S</italic><sub><italic>f</italic></sub> is the stop frequency.</p>
<p>The index of the stop frequency is of great importance for the computing <italic>FC</italic> on a specific intersection; and the idling time is also significant because 36.7% of the <italic>FC</italic> is wasted.</p>
<p>Stop frequency equals acceleration times. 2 diagrams (<xref rid="pone.0137477.s009" ref-type="supplementary-material">S8</xref> and <xref rid="pone.0137477.s010" ref-type="supplementary-material">S9</xref> Figs) will show the relationships between <italic>FC</italic> and velocity or acceleration.</p>
<p>From 2 diagrams (<xref rid="pone.0137477.s009" ref-type="supplementary-material">S8</xref> and <xref rid="pone.0137477.s010" ref-type="supplementary-material">S9</xref> Figs) and the table (<xref rid="pone.0137477.s011" ref-type="supplementary-material">S1 Table</xref>), it significantly shows that <italic>FC</italic> is so close with the positive acceleration. So, higher stop frequency means much more acceleration times and more <italic>FC</italic>.</p>
</sec>
<sec id="sec022">
<title>Improvement strategies</title>
<p>Here, some relative improvement strategies will be present for reducing vehicle <italic>FC</italic> on the area of the intersection. The detailed methods and proof schemes will be discussed in the next article.</p>
<p>First of all, traditional gasoline-powered vehicles should be replaced by the smaller and more efficient vehicles, i.e., hybrid, electric, biofuel, natural gas and etc. Meanwhile, STT for the engine can be promoted because it can reduce <italic>FC</italic> up to 15% during the intersection area. Otherwise, reducing vehicle arrivals in approaches is the fundamental way from changing private cars to bus transit. These are of great importance for sustainable development of arterial road traffic and saving <italic>FC</italic>.</p>
<p>Secondly, the intersections need to be broadened and well channelized for the approaches specially. Of course, it should be combined with the signal control design, especially with the phase design. The number of approach lanes is suggested to equal twice of the number of the road segment lanes; the classification of the lane function should be combined with the vehicle arrival rates; main traffic flow should be identified and should not change lanes frequently; the intersection area should be compressed as small as possible.</p>
<p>And then, optimized signal control strategies should be implemented for the arterial road intersections, for instance, multi-hour signal control schemes for the peak hours and non-peak hours, adaptive signal control method, and signal linear control technique; what’s more, <italic>FC</italic> should be one of the optimization indexes in the control system, and the detailed treatment adopted is that the volume to capacity ratio (V/C) should be lower than 0.8 for the approaches of the intersection. Meanwhile, a pre-signal could be used to the waiting area for through or left-turn traffic. Originally, waiting area setting is beneficial for increasing the intersection capacity, but increases the stop frequency and <italic>FC</italic> at the same time. However, a pre-signal is ahead of the next phase for through or left-turn traffic that the vehicles are allowed to enter the waiting area. Therefore, the vehicles enter the waiting area without extra stops and can save <italic>FC</italic>. Otherwise, the length of the waiting area should exceed 3 vehicles long distance.</p>
<p>Finally, a dynamic velocity control method can be used for the intersection. Here, 2 variable message signs (VMSs) and 3 groups of sensors will be installed along every approach of the intersection. So, the VOS is expected to be adjusted from type (a) to type (b) or from type (c) to type (b). The optimal objective of <italic>FC</italic> on the intersection and the decision variable of the VMS locations were brought forward; then, the optimal model of the dynamic velocity control was proposed after considering the distance, operating speed, vehicle arrival and other constraints; finally, a genetic algorithm was used to solve the model.</p>
</sec>
</sec>
<sec id="sec023">
<title>Future research prospects</title>
<p>Finally we gave an outlook to the future research. To begin with, we will conduct much more experimental tests with kinds of vehicles including new energy vehicles, buses and trucks. Moreover, <italic>FC</italic> study will be made under the background of connected vehicles and intelligent transportation systems (ITS) for the signalized intersections. Finally, <italic>FC</italic> for the whole intersection for the entire vehicles under different signal control strategies and different traffic states.</p>
</sec>
</sec>
<sec id="sec024" sec-type="conclusions">
<title>Conclusions</title>
<p>The preliminary findings are as follows:</p>
<list list-type="order">
<list-item><p>A test scheme of the <italic>FC</italic> was designed and the experiment was conducted on October, 2014 and July, 2015. So, 18 groups of experimental data were acquired including time, location, speed, engine velocity, engine load, injection timing of the test vehicle.</p></list-item>
<list-item><p><italic>FC</italic> composing and calculating method was put forward and the <italic>FCR</italic>s were calibrated. First, <italic>FC</italic> has four components, which are <italic>FC</italic><sub><italic>a</italic></sub>, <italic>FC</italic><sub><italic>d</italic></sub>, <italic>FC</italic><sub><italic>i</italic></sub>, and <italic>FC</italic><sub><italic>u</italic></sub>; these four parts are calculated by the recorded segment counts, time interval and corresponding <italic>FCR</italic> respectively. Then, the <italic>FCR</italic>s were calibrated by the collected data, and <italic>f</italic><sub>a</sub> is the highest and it’s almost twice of <italic>f</italic><sub>u</sub> and four times more of <italic>f</italic><sub>d</sub> and <italic>f</italic><sub>i</sub>. Finally, the <italic>FC</italic> of the test vehicle along the test route was calculated and the average value was 521.11 ml.</p></list-item>
<list-item><p>The characteristics of <italic>FC</italic>s were analyzed for the intersections along the test route. For a start, the definitions of the IID and IOT were given, and the average values were 1,262 meters and 625 seconds which accounted for 28.9% and 68.5% of the whole test route separately. Moreover, the percentages of the <italic>FC</italic>s on intersections in <italic>FC</italic>s were from 42.35% to 59.93% and the average percentage was 50.36%, and it means that more than half of the <italic>FC</italic> was used at the area of intersections compared with 28.9% of the IIDs. Eventually, the average <italic>FC</italic><sub>a</sub> was 109.05 ml accounting for 41.6% of the average <italic>FC</italic> on intersections; the average <italic>FC</italic><sub>i</sub> was 96.47 ml accounting for 36.8% of the average <italic>FCs</italic> on intersections; in other words, 78.4% of the <italic>FCs</italic> on intersections was used at the stages of acceleration and idling and the key influencing intersections were identified.</p></list-item>
<list-item><p>VOS and causes of the high <italic>FC</italic> for a specific intersection were discussed. Above all, VOS consisted of three types and was illustrated by the collected data. The next, the indexes of idling time, positive acceleration and its times were proved to be the most significant factors on <italic>FC</italic> on intersections. Final, four improvement strategies were proposed for saving <italic>FC</italic> on the area of the intersection.</p></list-item>
</list>
</sec>
<sec id="sec025">
<title>Supporting Information</title>
<supplementary-material id="pone.0137477.s001" xlink:href="info:doi/10.1371/journal.pone.0137477.s001" mimetype="application/vnd.ms-excel" position="float" xlink:type="simple">
<label>S1 Dataset</label>
<caption>
<title>Dataset.</title>
<p>(XLS)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s002" xlink:href="info:doi/10.1371/journal.pone.0137477.s002" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S1 Fig</label>
<caption>
<title>Test route at Harbin, China.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s003" xlink:href="info:doi/10.1371/journal.pone.0137477.s003" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S2 Fig</label>
<caption>
<title>The operation interface and the cable of the fuel consumption test system.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s004" xlink:href="info:doi/10.1371/journal.pone.0137477.s004" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S3 Fig</label>
<caption>
<title>A space-time diagram of the test vehicle along the test route.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s005" xlink:href="info:doi/10.1371/journal.pone.0137477.s005" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S4 Fig</label>
<caption>
<title>Vehicular operating status at an intersection.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s006" xlink:href="info:doi/10.1371/journal.pone.0137477.s006" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S5 Fig</label>
<caption>
<title>A space-velocity diagram of the test vehicle at the No. 2 intersection.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s007" xlink:href="info:doi/10.1371/journal.pone.0137477.s007" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S6 Fig</label>
<caption>
<title>A space-velocity diagram of the test vehicle at the No. 5 intersection.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s008" xlink:href="info:doi/10.1371/journal.pone.0137477.s008" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S7 Fig</label>
<caption>
<title>A space-velocity diagram of the test vehicle at the No. 6 intersection.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s009" xlink:href="info:doi/10.1371/journal.pone.0137477.s009" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S8 Fig</label>
<caption>
<title>A time-velocity-fuel consumption diagram of the type (a) of the VOS.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s010" xlink:href="info:doi/10.1371/journal.pone.0137477.s010" mimetype="image/tiff" position="float" xlink:type="simple">
<label>S9 Fig</label>
<caption>
<title>A velocity-acceleration-fuel consumption diagram of the type (a) of the VOS.</title>
<p>(TIF)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s011" xlink:href="info:doi/10.1371/journal.pone.0137477.s011" mimetype="application/msword" position="float" xlink:type="simple">
<label>S1 Table</label>
<caption>
<title>Technical Parameters of the Test Vehicle.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s012" xlink:href="info:doi/10.1371/journal.pone.0137477.s012" mimetype="application/msword" position="float" xlink:type="simple">
<label>S2 Table</label>
<caption>
<title>Average FCRs of the Test Vehicle for the Test Route.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s013" xlink:href="info:doi/10.1371/journal.pone.0137477.s013" mimetype="application/msword" position="float" xlink:type="simple">
<label>S3 Table</label>
<caption>
<title>Fuel Consumptions of the Test Vehicle for the Test Route.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s014" xlink:href="info:doi/10.1371/journal.pone.0137477.s014" mimetype="application/msword" position="float" xlink:type="simple">
<label>S4 Table</label>
<caption>
<title>Fuel Consumptions on Intersections.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s015" xlink:href="info:doi/10.1371/journal.pone.0137477.s015" mimetype="application/msword" position="float" xlink:type="simple">
<label>S5 Table</label>
<caption>
<title>Fuel Consumption for a Single Intersection.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
<supplementary-material id="pone.0137477.s016" xlink:href="info:doi/10.1371/journal.pone.0137477.s016" mimetype="application/msword" position="float" xlink:type="simple">
<label>S6 Table</label>
<caption>
<title>Characteristics of the Test Vehicular Operation and FC on the No. 6 Intersection.</title>
<p>(DOC)</p>
</caption>
</supplementary-material>
</sec>
</body>
<back>
<glossary>
<title>Nomenclature</title>
<def-list>
<def-item><term><italic>FC</italic></term>
<def><p>Fuel consumption</p></def>
</def-item>
<def-item><term><italic>FC<sub>a</sub></italic></term>
<def><p>Acceleration <italic>FC</italic></p></def>
</def-item>
<def-item><term><italic>FC<sub>d</sub></italic></term>
<def><p>Deceleration <italic>FC</italic></p></def>
</def-item>
<def-item><term><italic>FC<sub>i</sub></italic></term>
<def><p>Idling <italic>FC</italic></p></def>
</def-item>
<def-item><term><italic>FC<sub>u</sub></italic></term>
<def><p>Uniform velocity travelling <italic>FC</italic></p></def>
</def-item>
<def-item><term><italic>FC<sub>c</sub></italic></term>
<def><p><italic>FC</italic> on an intersection</p></def>
</def-item>
<def-item><term><italic>f<sub>a</sub></italic></term>
<def><p>Average acceleration <italic>FC</italic> rate</p></def>
</def-item>
<def-item><term><italic>f<sub>d</sub></italic></term>
<def><p>Average deceleration <italic>FC</italic> rate</p></def>
</def-item>
<def-item><term><italic>f<sub>i</sub></italic></term>
<def><p>Average idling <italic>FC</italic> rate</p></def>
</def-item>
<def-item><term><italic>f<sub>u</sub></italic></term>
<def><p>Average uniform velocity travelling <italic>FC</italic> rate</p></def>
</def-item>
<def-item><term><italic>q<sub>i</sub></italic></term>
<def><p>Fuel injection quantity for the <italic>i</italic><sup>th</sup> time interval</p></def>
</def-item>
<def-item><term><italic>τ<sub>i</sub></italic></term>
<def><p>Injection pulse width for the <italic>i</italic><sup>th</sup> record</p></def>
</def-item>
<def-item><term><italic>C</italic></term>
<def><p>Number of cylinders</p></def>
</def-item>
<def-item><term><italic>K</italic></term>
<def><p>Parameter of the fuel injection quantity</p></def>
</def-item>
<def-item><term><italic>t<sub>a</sub></italic></term>
<def><p>Average acceleration time</p></def>
</def-item>
<def-item><term><italic>t<sub>d</sub></italic></term>
<def><p>Average deceleration time</p></def>
</def-item>
<def-item><term><italic>t<sub>i</sub></italic></term>
<def><p>Average idling time</p></def>
</def-item>
<def-item><term><italic>t<sub>u</sub></italic></term>
<def><p>Average uniform velocity travelling time</p></def>
</def-item>
<def-item><term><italic>t</italic><sub>0</sub></term>
<def><p>Record time interval</p></def>
</def-item>
<def-item><term><italic>t</italic></term>
<def><p>Time variable</p></def>
</def-item>
<def-item><term><italic>t<sub>e</sub></italic></term>
<def><p>Injection time interval</p></def>
</def-item>
<def-item><term><italic>n<sub>a</sub></italic></term>
<def><p>Record acceleration segment count</p></def>
</def-item>
<def-item><term><italic>n<sub>d</sub></italic></term>
<def><p>Record deceleration segment count</p></def>
</def-item>
<def-item><term><italic>n<sub>i</sub></italic></term>
<def><p>Record idling segment count</p></def>
</def-item>
<def-item><term><italic>n<sub>u</sub></italic></term>
<def><p>Record uniform velocity travelling segment count</p></def>
</def-item>
<def-item><term><italic>n<sub>e</sub></italic></term>
<def><p>Engine velocity</p></def>
</def-item>
<def-item><term><italic>d</italic></term>
<def><p>Density of the gasoline</p></def>
</def-item>
<def-item><term><italic>S<sub>f</sub></italic></term>
<def><p>Stop frequency for the vehicles</p></def>
</def-item>
</def-list>
</glossary>
<ref-list>
<title>References</title>
<ref id="pone.0137477.ref001"><label>1</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Hu</surname> <given-names>XS</given-names></name>, <name name-style="western"><surname>Murgovski</surname> <given-names>N</given-names></name>, <name name-style="western"><surname>Johannesson</surname> <given-names>LM</given-names></name>, <name name-style="western"><surname>Egardt</surname> <given-names>B</given-names></name>. <article-title>Comparison of three electrochemical energy buffers applied to a hybrid bus powertrain with simultaneous optimal sizing and energy management</article-title>. <source>IEEE T Intel Transp</source>. <year>2014</year>; <volume>15</volume>(<issue>3</issue>): <fpage>1193</fpage>–<lpage>1205</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref002"><label>2</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Yang</surname> <given-names>C</given-names></name>, <name name-style="western"><surname>Jiao</surname> <given-names>XH</given-names></name>, <name name-style="western"><surname>Li</surname> <given-names>L</given-names></name>, <name name-style="western"><surname>Zhang</surname> <given-names>YH</given-names></name>, <name name-style="western"><surname>Zhang</surname> <given-names>LP</given-names></name>, <name name-style="western"><surname>Song</surname> <given-names>J</given-names></name>. <article-title>Robust coordinated control for hybrid electric bus with single-shaft parallel hybrid powertrain</article-title>. <source>IET Control Theory Appl</source>. <year>2015</year>; <volume>9</volume>(<issue>2</issue>):<fpage>270</fpage>–<lpage>282</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref003"><label>3</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Hu</surname> <given-names>XS</given-names></name>, <name name-style="western"><surname>Murgovski</surname> <given-names>N</given-names></name>, <name name-style="western"><surname>Johannesson</surname> <given-names>LM</given-names></name>, <name name-style="western"><surname>Egardt</surname> <given-names>B</given-names></name>. <article-title>Energy efficiency analysis of a series plug-in hybrid electric bus with different energy management strategies and battery sizes</article-title>. <source>Appl Energ</source>. <year>2013</year>; <volume>111</volume>: <fpage>1001</fpage>–<lpage>1009</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref004"><label>4</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Li</surname> <given-names>L</given-names></name>, <name name-style="western"><surname>Yang</surname> <given-names>C</given-names></name>, <name name-style="western"><surname>Zhang</surname> <given-names>YH</given-names></name>, <name name-style="western"><surname>Zhang</surname> <given-names>LP</given-names></name>, <name name-style="western"><surname>Song</surname> <given-names>J</given-names></name>. <article-title>Correctional DP-based energy management strategy of plug-in hybrid electric bus for city-bus route</article-title>. <source>IEEE T Veh Technol</source>. <year>2015</year>; <volume>64</volume>(<issue>7</issue>): <fpage>2792</fpage>–<lpage>2803</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref005"><label>5</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Sun</surname> <given-names>C</given-names></name>, <name name-style="western"><surname>Moura</surname> <given-names>S J</given-names></name>, <name name-style="western"><surname>Hu</surname> <given-names>XS</given-names></name>, <name name-style="western"><surname>Hedrick</surname> <given-names>JK</given-names></name>, <name name-style="western"><surname>Sun</surname> <given-names>FC</given-names></name>. <article-title>Dynamic traffic feedback data enabled energy management in plug-in hybrid electric vehicles</article-title>. <source>IEEE T Contr Syst T</source>. <year>2015</year>; <volume>23</volume>(<issue>3</issue>): <fpage>1075</fpage>–<lpage>1086</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref006"><label>6</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Zheng</surname> <given-names>CH</given-names></name>, <name name-style="western"><surname>Kim</surname> <given-names>NW</given-names></name>, <name name-style="western"><surname>Park</surname> <given-names>YI</given-names></name>, <name name-style="western"><surname>Lim</surname> <given-names>WS</given-names></name>, <name name-style="western"><surname>Cha</surname> <given-names>SW</given-names></name>, <name name-style="western"><surname>Xu</surname> <given-names>GQ</given-names></name>. <article-title>The effect of battery temperature on total fuel consumption of fuel cell hybrid vehicles</article-title>. <source>International Journal of Hydrogen Energy</source>. <year>2013</year>; <volume>38</volume>: <fpage>5192</fpage>–<lpage>5200</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref007"><label>7</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Hu</surname> <given-names>XS</given-names></name>, <name name-style="western"><surname>Murgovski</surname> <given-names>N</given-names></name>, <name name-style="western"><surname>Johannesson</surname> <given-names>LM</given-names></name>, <name name-style="western"><surname>Egardt</surname> <given-names>B</given-names></name>. <article-title>Optimal dimensioning and power management of a fuel cell battery hybrid bus via convex programming</article-title>. <source>IEEE-ASME T Mech</source>. <year>2015</year>; <volume>20</volume>(<issue>1</issue>): <fpage>457</fpage>–<lpage>468</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref008"><label>8</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Hu</surname> <given-names>XS</given-names></name>, <name name-style="western"><surname>Johannesson</surname> <given-names>LM</given-names></name>, <name name-style="western"><surname>Murgovski</surname> <given-names>N</given-names></name>, <name name-style="western"><surname>Egardt</surname> <given-names>B</given-names></name>. <article-title>Longevity-conscious dimensioning and power management of the hybrid energy storage system in a fuel cell hybrid electric bus</article-title>. <source>Appl Energ</source>. <year>2015</year>; <volume>137</volume>: <fpage>913</fpage>–<lpage>924</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref009"><label>9</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Li</surname> <given-names>ZL</given-names></name>, <name name-style="western"><surname>Lin</surname> <given-names>Y</given-names></name>, <name name-style="western"><surname>Xu</surname> <given-names>G</given-names></name>. <article-title>Simulation and experimental study for a micro hybrid electric car with smart start—stop system</article-title>. <source>China Mechanical Engineering</source>. <year>2010</year>; <volume>21</volume>(<issue>1</issue>): <fpage>110</fpage>–<lpage>114</lpage>. (In Chinese)</mixed-citation></ref>
<ref id="pone.0137477.ref010"><label>10</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Staubach</surname> <given-names>M</given-names></name>, <name name-style="western"><surname>Schebitz</surname> <given-names>N</given-names></name>, <name name-style="western"><surname>Koster</surname> <given-names>F</given-names></name>, <name name-style="western"><surname>Kuck</surname> <given-names>D</given-names></name>. <article-title>Evaluation of an eco-driving support system</article-title>. <source>Transport Res F-TRAF</source>. <year>2014</year>; <volume>27</volume>: <fpage>11</fpage>–<lpage>21</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref011"><label>11</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Lai</surname> <given-names>WT</given-names></name>. <article-title>The effects of eco-driving motivation, knowledge and reward intervention on fuel efficiency</article-title>. <source>Transport Res D-TR E</source>. <year>2015</year>; <volume>34</volume>: <fpage>155</fpage>–<lpage>160</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref012"><label>12</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>McIlroy</surname> <given-names>RC</given-names></name>, <name name-style="western"><surname>Stanton</surname> <given-names>NA</given-names></name>. <article-title>A decision ladder analysis of eco-driving: the first step towards fuel-efficient driving behaviour</article-title>. <source>Ergonomics</source>. <year>2015</year>; <volume>58</volume>(<issue>6</issue>): <fpage>866</fpage>–<lpage>882</lpage>. <comment>doi: <ext-link ext-link-type="uri" xlink:href="http://dx.doi.org/10.1080/00140139.2014.997807" xlink:type="simple">10.1080/00140139.2014.997807</ext-link></comment> <object-id pub-id-type="pmid">25604541</object-id></mixed-citation></ref>
<ref id="pone.0137477.ref013"><label>13</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Evans</surname> <given-names>LE</given-names></name>, <name name-style="western"><surname>Robert</surname> <given-names>H</given-names></name>, <name name-style="western"><surname>Tenny</surname> <given-names>L</given-names></name>. <article-title>Multivariate analysis of traffic factors related to fuel consumption in urban driving</article-title>. <source>Transport Sci</source>. <year>1976</year>; <volume>10</volume>(<issue>2</issue>): <fpage>213</fpage>–<lpage>214</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref014"><label>14</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Herman</surname> <given-names>R</given-names></name>, <name name-style="western"><surname>Ardekani</surname> <given-names>S</given-names></name>. <article-title>The influence of stops on vehicle fuel consumption in urban traffic</article-title>. <source>Transport Sci</source>. <year>1985</year>; <volume>19</volume>(<issue>1</issue>): <fpage>1</fpage>–<lpage>12</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref015"><label>15</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Rakha</surname> <given-names>H</given-names></name>, <name name-style="western"><surname>Ding</surname> <given-names>YL</given-names></name>. <article-title>Impact of stops on vehicle fuel consumption and emissions</article-title>. <source>J Transp Eng-ASCE</source>. <year>2003</year>; <volume>129</volume>(<issue>1</issue>): <fpage>23</fpage>–<lpage>32</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref016"><label>16</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Ahn</surname> <given-names>K</given-names></name>, <name name-style="western"><surname>Rakham</surname> <given-names>H</given-names></name>, <name name-style="western"><surname>Trani</surname> <given-names>A</given-names></name>, <name name-style="western"><surname>Van Aerde</surname> <given-names>M</given-names></name>. <article-title>Estimating vehicle fuel consumption and emissions based on instantaneous speed and acceleration levels</article-title>. <source>J Transp Eng-ASCE</source>. <year>2002</year>; <volume>128</volume>(<issue>2</issue>): <fpage>182</fpage>–<lpage>190</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref017"><label>17</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Luo</surname> <given-names>XH</given-names></name>. <article-title>Researching of the fuel consumption of vehicles at intersections</article-title>. <source>Journal of Beijing Institute of Civil Engineering and Architecture</source>. <year>1997</year>; <volume>13</volume>(<issue>4</issue>): <fpage>25</fpage>–<lpage>29</lpage>. (In Chinese)</mixed-citation></ref>
<ref id="pone.0137477.ref018"><label>18</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Zhang</surname> <given-names>WH</given-names></name>, <name name-style="western"><surname>Wang</surname> <given-names>W</given-names></name>, <name name-style="western"><surname>Yin</surname> <given-names>HL</given-names></name>, <name name-style="western"><surname>Hu</surname> <given-names>G</given-names></name>. <article-title>Study on vehicle fuel consumption of signalized intersections</article-title>. <source>Journal of Southeast University (Natural Science Edition)</source>. <year>2002</year>; <volume>32</volume>(<issue>2</issue>): <fpage>249</fpage>–<lpage>251</lpage>. (In Chinese)</mixed-citation></ref>
<ref id="pone.0137477.ref019"><label>19</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Xiang</surname> <given-names>QJ</given-names></name>, <name name-style="western"><surname>Wang</surname> <given-names>W</given-names></name>, <name name-style="western"><surname>Lu</surname> <given-names>J</given-names></name>. <article-title>Research on fuel consumption at signalized intersection</article-title>. <source>Journal of Highway and Transportation Research and Development</source>. <year>2004</year>; <volume>21</volume>(<issue>12</issue>): <fpage>100</fpage>–<lpage>102</lpage>. (In Chinese)</mixed-citation></ref>
<ref id="pone.0137477.ref020"><label>20</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Feng</surname> <given-names>Y Q</given-names></name>, <name name-style="western"><surname>Zhang</surname> <given-names>YP</given-names></name>, <name name-style="western"><surname>Leng</surname> <given-names>JQ</given-names></name>, <name name-style="western"><surname>Sun</surname> <given-names>G</given-names></name>, <name name-style="western"><surname>Feng</surname> <given-names>YH</given-names></name>. <article-title>Model for evaluation on fuel economy of urban intersection</article-title>. <source>Journal of Harbin Institute of Technology (New Series)</source>. <year>2011</year>; <volume>18</volume>(<issue>3</issue>): <fpage>79</fpage>–<lpage>83</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref021"><label>21</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Li</surname> <given-names>L</given-names></name>, <name name-style="western"><surname>Wang</surname> <given-names>FY</given-names></name>. <article-title>Cooperative driving at blind crossings using intervehicle communication</article-title>. <source>IEEE T Veh Technol</source>. <year>2006</year>; <volume>55</volume>(<issue>6</issue>): <fpage>1712</fpage>–<lpage>1724</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref022"><label>22</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Asadi</surname> <given-names>B</given-names></name>, <name name-style="western"><surname>Vahidi</surname> <given-names>A</given-names></name>. <article-title>Predictive cruise control: utilizing upcoming traffic signal information for improving fuel economy and reducing trip time</article-title>. <source>IEEE T Contr Syst T</source>. <year>2011</year>; <volume>19</volume>(<issue>3</issue>): <fpage>707</fpage>–<lpage>714</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref023"><label>23</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Mahler</surname> <given-names>G</given-names></name>, <name name-style="western"><surname>Vahidi</surname> <given-names>A</given-names></name>. <article-title>An optimal velocity-planning scheme for vehicle energy efficiency through probabilistic prediction of traffic-signal timing</article-title>. <source>IEEE T Intell Transp</source>. <year>2014</year>; <volume>15</volume>(<issue>6</issue>): <fpage>2516</fpage>–<lpage>2523</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref024"><label>24</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Bie</surname> <given-names>YM</given-names></name>, <name name-style="western"><surname>Wang</surname> <given-names>DH</given-names></name>, <name name-style="western"><surname>Qi</surname> <given-names>HS</given-names></name>. <article-title>Prediction model of bus arrival time at signalized intersection using GPS data</article-title>. <source>J Transp Eng-ASCE</source>. <year>2012</year>; <volume>138</volume>(<issue>1</issue>): <fpage>12</fpage>–<lpage>20</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref025"><label>25</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Xia</surname> <given-names>HT</given-names></name>, <name name-style="western"><surname>Boriboonsomsin</surname> <given-names>K</given-names></name>, <name name-style="western"><surname>Barth</surname> <given-names>M</given-names></name>. <article-title>Dynamic eco-driving for signalized arterial corridors and its indirect network-wide energy/emissions benefits</article-title>. <source>J Intell Transport S</source>. <year>2013</year>; <volume>17</volume>(<issue>1</issue>): <fpage>31</fpage>–<lpage>41</lpage>.</mixed-citation></ref>
<ref id="pone.0137477.ref026"><label>26</label><mixed-citation publication-type="journal" xlink:type="simple"><name name-style="western"><surname>Zhang</surname> <given-names>R</given-names></name>, <name name-style="western"><surname>Yao</surname> <given-names>EJ</given-names></name>. <article-title>Eco-driving at signalised intersections for electric vehicles</article-title>. <source>IET Intell Transp Sy</source>. <year>2015</year>; <volume>9</volume>(<issue>5</issue>): <fpage>488</fpage>–<lpage>497</lpage>.</mixed-citation></ref>
</ref-list>
</back>
</article>