Data quality report

Region: Northern California

Season: Northern California Fall 2019 Thursday

Report generated: 2021-08-19

https://www.replicahq.com

support@replicahq.com

Review the Overall Summary

Table of contents

• Quality metrics

  • Origin-Destination Flows

  • Traffic

  • Public Transportation

  • On-Demand Transportation: TNC + Taxi

  • Commercial Vehicles

  • Overall summary

• Additional Metrics

  • Mode split
  • Trip distance/duration summaries
  • Comute flows by county

About this report

This report describes how Replica model compares to other data sources describing movement in the region, including relevant Census surveys aggregates and observed volumes of traffic, transit boardings and non-motorized trip counts in the region. Replica describes a typical week of travel for a specific three-month (quarter) period, and comparisons are made with the data collected within the relevant period and aggregated to represent a typical day of travel.

Each section of the report provides details on the accuracy of the model within the relevant comparison category.

Origin-Destination Flows

This section compares overall county-to-county work commute characteristics against Census Transportation Planning Product (CTPP) data. Replica models all trips by residents of the core modeling region as well as trips by residents of the extended region who work in the core. A comparison of the distribution of number of departures within each hour by county of origin is provided.

Note: Replica counts are scaled so that the total number of trips matches the CTPP, in order to account for discrepancies between average daily travel patterns and self-reported survey responses.

CTPP movements, Figure 1: Commute departures by hour by county

Notes

• CTPP 2012-2016 is used as the source of commute volumes for county-to-county and significant tract-to-tract flows, as well as reported departure times.
• Commute flows should only be compared with CTPP for typical weekdays (not weekends).

Note: Error and Bound numbers for this section are 1 - p, where p is the correlation coefficient.

		Error	Bound	✓
Subcategory	Bucket
Commute Departures per Hour	By County	0.115796	0.100000	≈

Traffic

Passenger vehicle volumes are compared to averaged seasonal daily volumes collected at multiple locations within the region and aggregated over different road volume groups and road categories as recommended by FHWA.

Auto, Figure 1: Map of the traffic volumes sensor locations for the simulated region/season.

Daily totals

Auto, Figure 2: Total daily volumes: by road type (top) and volume (bottom)

	Error	Bound	✓
Bucket
<10k daily	0.556141	0.500000
10-20k daily	0.248539	0.350000	✓
20-40k daily	0.153814	0.250000	✓
40-60k daily	0.102026	0.200000	✓
60-80k daily	0.073497	0.150000	✓
80-100k daily	0.047824	0.120000	✓
>100k daily	0.066117	0.100000	✓

Hourly totals

Total hourly volumes are generally less accurate in the night hours. Due to privacy considerations Replica does not reproduce most of the rare nighttime (not “typical”) trips.

	Error	Bound	✓
Bucket
Arterials hourly	0.312412	nan	NA
Freeways hourly	0.240152	nan	NA

Auto, Figure 3: Hourly volumes on major (>=50,000 daily volume) roadways

Average Speeds by Hour

This section reports on Replica traffic speeds on different categories of roadways as compared to the observed data. This comparison focuses only on peak commute hours: 5AM to 10AM and 3PM to 7PM.

Auto, Figure 4: Hourly auto speeds

		Error	Bound	✓
Subcategory	Bucket
Morning Peak	Other roads	nan	0.300000	NA
Evening Peak	Other roads	nan	0.300000	NA
Morning Peak	Arterials	nan	0.150000	NA
Evening Peak	Arterials	nan	0.150000	NA
Morning Peak	Freeways	nan	0.100000	NA
Evening Peak	Freeways	nan	0.100000	NA

Notes

• Observed volume counts may contain outliers due to ambiguities in sensor locations and malfunctioning sensor hardware.
• Detailed comparisons are available in multiple formats (csv, geojson, shp) in the Ground Truth section of the Replica downloads page (https://my.replicahq.com/downloads).

Public Transportation

Public transit ridership metrics are compared against data provided by regional transit agencies. Accuracy metrics are computed for total number of boardings per transit line (number of unlinked trips), by transit type and by passenger volume group as recommended by FTA.

Daily totals

Public Transit, Figure 1: Total daily number of boardings: by volume (top), route type (middle), and agency (bottom)

Notes

• Public transit ridership accuracy is reported as percentage error of total ridership per volume category and service type.
• Per-line comparisons are available in multiple formats (csv, geojson, shp) in the Ground Truth section of the Replica downloads page (https://my.replicahq.com/downloads).

			Error	Bound	✓
Category	Subcategory	Bucket
Transit	Regionwide Total	Daily Trips	nan	0.050000	NA
		Daily Boardings	0.015909	0.050000	✓
	Daily Volumes	<2000 daily	0.182404	1.000000	✓
		2000-5000 daily	0.089388	0.500000	✓
		5000-10000 daily	0.081727	0.300000	✓
		10000-20000 daily	0.121556	0.200000	✓
		>20000 daily	0.028674	0.150000	✓

On-Demand Transportation: TNC + Taxi

Region-wide on-demand trips per hour

On-demand auto, Figure 1: Total number of person trips by hour

Daily Person Trips by origin/destination tract

On-demand auto, Figure 2: Total daily person trips by origin tract (top) and destination tract (bottom)

On demand origin/destinations by tract/hour

On-demand auto, Figure 3: Hourly person trips by origin tract (top) and destination tract (bottom)

		Error	Bound	✓
Subcategory	Bucket
By hour	Regionwide	0.293496	0.250000
Daily Volumes by Origin Tract	<1000 daily	0.282124	inf	✓
	1000+ daily	0.023289	0.250000	✓
Daily Volumes by Destination Tract	<1000 daily	0.279368	inf	✓
	1000+ daily	0.043797	0.250000	✓
Hourly Volumes by Origin Tract	<1000 daily	0.722790	nan	NA
	1000+ daily	0.183232	nan	NA
Hourly Volumes by Destination Tract	<1000 daily	0.629437	nan	NA
	1000+ daily	0.157889	nan	NA

Commercial Vehicles

In this section commercial freight traffic volumes represented in Replica are broken out separately and compared to the observed volumes of trucks in a select number of count locations where data exists.

Daily totals

Freight, Figure 1: Total daily commercial freight traffic by volume and vehicle class

		Error	Bound	✓
Subcategory	Bucket
Daily Volumes	Total	0.001411	0.250000	✓

Overall summary

			Error	Bound	✓
Category	Subcategory	Bucket
Origin-Destination Flows	Commute Departures per Hour	By County	0.115796	0.100000	≈
Auto	Daily Volumes	<10k daily	0.556141	0.500000
		10-20k daily	0.248539	0.350000	✓
		20-40k daily	0.153814	0.250000	✓
		40-60k daily	0.102026	0.200000	✓
		60-80k daily	0.073497	0.150000	✓
		80-100k daily	0.047824	0.120000	✓
		>100k daily	0.066117	0.100000	✓
Traffic Speeds	Morning Peak	Other roads	nan	0.300000	NA
	Evening Peak	Other roads	nan	0.300000	NA
	Morning Peak	Arterials	nan	0.150000	NA
	Evening Peak	Arterials	nan	0.150000	NA
	Morning Peak	Freeways	nan	0.100000	NA
	Evening Peak	Freeways	nan	0.100000	NA
Transit	Regionwide Total	Daily Trips	nan	0.050000	NA
		Daily Boardings	0.015909	0.050000	✓
	Daily Volumes	<2000 daily	0.182404	1.000000	✓
		2000-5000 daily	0.089388	0.500000	✓
		5000-10000 daily	0.081727	0.300000	✓
		10000-20000 daily	0.121556	0.200000	✓
		>20000 daily	0.028674	0.150000	✓
On demand auto	Daily Volumes by Origin Tract	1000+ daily	0.023289	0.250000	✓
	Daily Volumes by Destination Tract	1000+ daily	0.043797	0.250000	✓
Freight	Daily Volumes	Total	0.001411	0.250000	✓

Additional Metrics

Mode split

This section reports on the total number of travel activities (linked trips) by their primary travel mode.

	Total activities	Percent
Mode
Biking	903817	1.34
Carpool	7518628	11.16
Commercial	2783947	4.13
On demand auto	525288	0.78
Other travel mode	3077601	4.57
Private auto	36964079	54.88
Public transit	1517999	2.25
Walking	14069135	20.89

Mode split, Table 1: Total travel activities by mode

Trip generation summaries

	Avg trips per household	Avg trips per person
Household size
1	3.80	3.80
2	7.72	3.86
3	10.55	3.52
4	12.75	3.19
5 plus	18.68	2.96

Trip summaries, Table 1: Average number of trips per person/household by household size

	Total trips	Percent
Purpose
Commercial	2833665	4.21
Eat	3766318	5.59
Home	21564206	32.01
Lodging	589875	0.88
Maintenance	3030666	4.50
Other activity type	936036	1.39
Recreation	3310428	4.91
Region departure	173378	0.26
School	3882157	5.76
Shop	10721102	15.92
Social	6843515	10.16
Stage	61358	0.09
Work	9647790	14.32

Trip summaries, Table 2: Distribution of trip purpose

Trip distance/duration summaries

Biking

Carpool

On demand auto

Private auto

Public transit

Walking

Trip summaries, Figure 1: Distance/duration distributions by mode, trip purpose. For informational purposes only.

Notes

• Trip distance and duration summaries are provided for informational purposes only.

Comute flows by county

Commute flows by county, Figure 1: Commute departures by hour vs CTPP broken out by county