SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

San Francisco DTA Model: Working Model Calibration

Part 2: Results

Renee Alsup

DTA Peer Review Panel MeetingJuly 25th, 2012

SAN FRANCISCO COUNTY TRANSPORTATION AUTHORITY

Agenda

• 9:00 Background• 9:30 Technical Overview – Part 1

• Development Process and Code Base/Network Development

• 10:15 Break• 10:30 Technical Overview – Part 2

• Calibration and Integration Strategies

• 12:00 Working Lunch / Discussion• 2:00 Panel Caucus (closed)• 3:30 Panel report• 5:30 Adjourn

3

Outline

• Summary Results• Large Outliers• Select Link Analysis• Corridor Plots• Key Findings Results from July

11 Calibration Run (pb_july11_300p_FT )

Summary Results

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Link Volumes

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Movement Volumes

7

Time-of-Day

8

Average Movement Volumes by Facility Type

Facility TypeNumber of

Counts Observed Modeled DifferencePercent

DifferencePercent RMSE

Freeway 4 1016 931 -85 -8% 38%

Major Arterial 835 504 412 -92 -18% 61%

Minor Arterial 490 211 251 40 19% 94%

Collector 357 133 47 -85 -64% 109%

Local 150 41 19 -23 -55% 114%

Total 1,836 317 267 -50 -16% 76%

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Average Movement Volumes by Turn Type

Turn TypeNumber of

Counts Observed Modeled DifferencePercent

DifferencePercent RMSE

Through 696 675 598 -77 -11% 54%

Left Turn 524 90 57 -32 -36% 132%

Right Turn 586 110 74 -36 -33% 103%

Total 1,814 317 267 -50 -16% 76%

Large Outliers

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Worst Links with Volume too Low

LinkID Label Facility TypeNum Lanes

Start Time

Count Volume

Model Volume

15034 HARRISON ST Major Art 5 17:00 2093 41613221 SUNSET BLVD Major Art 3 17:00 2514 84913221 SUNSET BLVD Major Art 3 16:00 2248 91313223 SUNSET BLVD Major Art 3 17:00 2204 90528677 GEARY BLVD Collector 1 17:00 1300 4432834 HARRISON ST Major Art 5 17:00 1443 20016180 FOLSOM ST Major Art 4 17:00 1702 46715034 HARRISON ST Major Art 5 16:00 1664 43823818 GEARY BLVD Collector 1 17:00 1505 29228677 GEARY BLVD Collector 1 16:00 1264 59

12

Worst Links with Volume too High

LinkID LabelFacility Type

Num Lanes

Start Time

Count Volume

Model Volume

24936 GEARY BLVD Major Art 3 16:00 1499 266924936 GEARY BLVD Major Art 3 17:00 1575 264217742 STOCKTON ST Major Art 4 16:00 916 186622475 VAN NESS AVE Major Art 3 16:00 1027 18309011484 STOCKTON ST Major Art 3 16:00 794 158425174 GEARY BLVD Major Art 3 16:00 1629 240021090 TURK ST Major Art 2 16:00 641 140624943 GEARY BLVD Major Art 3 16:00 1799 255823909 GEARY BLVD Major Art 3 16:00 1835 255222762 GEARY BLVD Major Art 3 16:00 1473 2138

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Speed Outliers

• Broadway Tunnel- Free-flow speed is 25mph-30mph. The actual speed limit in the tunnel is 40mph.

• Geneva from Ocean to Cayuga – Modeled free-flow speed is 10 mph higher than speed limit.

Solution: Fix free-flow speeds by making sure they fall in the right area type.

Select Link Analysis

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I-80 EB Select Link (1/2)

• As expected, much

of the traffic comes

from freeways.

• We also see a

good amount of

traffic taking Oak

to get onto I-80

from the Western

region and taking

1st St and 2nd St

North of Market.

Selected Link

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I-80 EB Select Link (2/2)

• 1st and 2nd Street are heavily used by people going from CBD to get onto the

freeway.

• Embarcadero is used, but less than 1st or 2nd St.

• There isn’t a lot of traffic moving Eastward to get onto the freeway between

I-80 and Market. People have mostly entered the freeway by then, or they

move East while they are North of Market.

Selected Link

17

I-80 EB On-Ramps

• Most traffic gets to the

on-ramps on 1st St, 2nd St

and The Embarcadero

• Vehicles further North

are more likely to take

Embarcadero South to get

onto I-80 than to use the

local streets

I-80 WB Select Link

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Selected Link

• Much of the traffic

entering on I-80 is

destined for the

Southern region

• Freeways take much

of the traffic, but

some takes

Freemont to Pine or

9th St to Van Ness

and Franklin

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I-80 WB On-Ramps

• Most vehicles use

the first ramp at

Harrison & 4th

• Because the first

ramp isn’t

congested very

few vehicles

continue on

Harrison to

second ramp

Select Links

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19th Ave NB

• Most of the traffic on 19th Ave

is just straight through on

Hwy 1

• Very little traffic from here is

going East or West – Sunset

Blvd and Great Hwy used for

traffic going West

21

19th Ave SB

• Very similar to NB

traffic pattern

• Picks up some traffic

in the park headed

South

22

Sunset Blvd NB

• Almost no traffic going

to the Golden Gate

Bridge

• Mostly trips from I-280

and Hwy 1 to local

areas South of the park

• Need to figure out why

so few people are using

Sunset to go through

the park

23

Sunset Blvd SB

• Almost no traffic

coming from Golden

Gate Bridge. Mostly

comes from South of

the park

• Significant amount of

traffic from Lincoln

Way coming over from

the CBD on Fell

24

Golden Gate Bridge Outbound

• Origin of traffic seems

evenly split between

East and West regions

• Significant number of

trips on Geary

between Hwy 1 and

Franklin/Van Ness to

change which entry

point to the bridge is

used

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Golden Gate Bridge Inbound

• East/West split is similar

to outbound

• Don’t have people using

Geary to move between

East and West regions

here

• Very few vehicles going

Southwest use any

other path besides Hwy

1

Corridor Plots

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Ocean: Miramar to 19th Ave

Big drop at Junipero Serra

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Townsend: 2nd St to 7th St

Big drop at Junipero Serra

Vehicles turn left at 4th St to get to I-280 entrance ramps

Key Findings

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Key Findings

• The model is free from obvious gridlock• There generally appears to be less

congestion than anticipated—perhaps due to the removal of the bus-only lanes

• A number of outliers appear to be driven by specific network movements—such as freeway on-ramps

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Next Steps

• Incorporate a network coding strategy for the bus-only lanes.

• Incorporate the effect of slope into the speed-flow parameters based on additional analysis of the data collected.

• Update the time-of-day profile of the demand to better match the higher volumes observed in the 5-6 pm hour.

• Identify origins - destinations markets where SF-CHAMP is over- or under-estimating vehicle demand.

• Deal with pedestrian/bicycle friction?

Questions?