san francisco dta model: working model calibration part 2: results renee alsup
DESCRIPTION
San Francisco DTA Model: Working Model Calibration Part 2: Results Renee Alsup. DTA Peer Review Panel Meeting July 25 th , 2012. Agenda. 9:00Background 9:30Technical Overview – Part 1 Development Process and Code Base/Network Development 10:15Break 10:30Technical Overview – Part 2 - PowerPoint PPT PresentationTRANSCRIPT
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
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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
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Time-of-Day
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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
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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
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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
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19th Ave SB
• Very similar to NB traffic pattern
• Picks up some traffic in the park headed South
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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
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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
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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?