* Transit/rideshare removes only \~50,000 trips from the total
* City’s official estimate: 66,000 trips/day (unrealistic by all comparisons)
Conclusion:
Every reasonable method of estimating traffic volume—demographic modeling, lane use, engineering-based wear, observed transit use, and real-world observation—points to daily traffic on 19th Avenue being at least 2 to 3 times higher than the city’s official figure of 66,000 vehicles. A conservative real-world floor is 140,000, with high probability that actual daily traffic exceeds 200,000 vehicles.
This undercount misinforms policy decisions about safety, infrastructure, congestion management, and funding priorities. It falsely justifies road diet strategies and traffic calming policies while concealing the actual load being handled by the West Side’s primary north-south arterial.
Building on the population-based volume estimates above, we can further quantify both how many people are driving — a metric rarely acknowledged in transportation policy.
West Side Population Recap:
Total residents: 360,000
Children (~15%): 54,000
Remaining adults: 306,000
Non-drivers using public transit, ride-shares, or buses: ~92,500 (67,500 on Muni Metro, 25,000 on ride-share or the 28 bus)
Estimated number of drivers: ~213,500
To be conservative, let’s assume that only 75% of the adult population actively drives (to account for retirees, remote workers, etc.), which results in:
Estimated daily drivers or riders: ~163,125
Now estimate daily trip volume:
Assume 3 car trips/day per person (commute, errands, drop-offs), a conservative figure
Total passenger trips: 163,125 × 3 = 489,375
Assume average car occupancy = 1.5 people
Estimated daily vehicle trips = 489,375 ÷ 1.5 = ~326,250 car trips per day generated on the West Side
This is far beyond the 66,000 vehicle trips/day claimed by SFMTA for 19th Avenue, and it only accounts for residents — not through-commuters, commercial vehicles, or visitors.
I have read this analysis intently, and have nothing to suggest, other than for all persons to carefully assess the relative utility of their location and transport choices in this world of gradually constricting options.
Comprehensive Traffic Volume & Impact Analysis for 19th Avenue, San Francisco
Population-Based Traffic Demand:
* Richmond District (official figure): 60,000
* Sunset + Forest Hill + Parkside + West Portal + St. Francis Wood: 250,000
* South of Sloat (Parkmerced, SF State, Ingleside): 50,000
* Total West Side catchment: 360,000 residents
Assume 50% of residents drive = 180,000 drivers
At 2 trips per day = 360,000 total trips/day
Assume one-third use 19th Ave = 120,000 vehicle trips/day just from the West Side population
Lane Volume and Flow Estimate:
* 6 total lanes (3 in each direction), 25 blocks
* 120 cars per block (peak), flowing 3 full rotations/hour
* Peak hours = 108,000 vehicle movements
* Midday = 54,000
* Night = 54,000
* Total = approximately 216,000 vehicle trips/day
Pavement Wear-Based Estimate:
* Roads are designed for about 1 million ESALs per year
* Based on observed repaving frequency (once every 1-2 years per segment), we assume actual ESAL load equals or exceeds 1 million/year
* Weighted average ESAL per vehicle = \~0.02
* 1,000,000 ÷ 0.02 = 50 million vehicle passes/year
* That’s approximately 137,000 vehicle passes/day
Transit and Ride-Share Ridership:
* Muni 28/28R bus ridership: \~16,200 daily riders
* Estimated ride-share (Uber/Lyft) trips: \~100,000 per day citywide
* Assuming one-third are west-side trips: \~34,000
* Combined: \~50,000 people not using personal vehicles
* With 360,000 West Side residents, this implies over 85% of trips are via private car
Time-of-Day Flow and Weekend Traffic:
* Night traffic flows faster, meaning higher volume is processed during those hours
* Weekends see bumper-to-bumper traffic from 9am to 6pm
* SFMTA’s estimate does not account for weekend or overnight flows, further undercutting its accuracy
Final Summary of Estimated Daily Traffic on 19th Ave:
* Population-based: 120,000–140,000 trips/day
* Lane capacity and vehicle flow: 180,000–216,000 trips/day
* Pavement wear-based estimate: \~137,000 trips/day
* Transit/rideshare removes only \~50,000 trips from the total
* City’s official estimate: 66,000 trips/day (unrealistic by all comparisons)
Conclusion:
Every reasonable method of estimating traffic volume—demographic modeling, lane use, engineering-based wear, observed transit use, and real-world observation—points to daily traffic on 19th Avenue being at least 2 to 3 times higher than the city’s official figure of 66,000 vehicles. A conservative real-world floor is 140,000, with high probability that actual daily traffic exceeds 200,000 vehicles.
This undercount misinforms policy decisions about safety, infrastructure, congestion management, and funding priorities. It falsely justifies road diet strategies and traffic calming policies while concealing the actual load being handled by the West Side’s primary north-south arterial.
Driving Behavior on the West Side
Building on the population-based volume estimates above, we can further quantify both how many people are driving — a metric rarely acknowledged in transportation policy.
West Side Population Recap:
Total residents: 360,000
Children (~15%): 54,000
Remaining adults: 306,000
Non-drivers using public transit, ride-shares, or buses: ~92,500 (67,500 on Muni Metro, 25,000 on ride-share or the 28 bus)
Estimated number of drivers: ~213,500
To be conservative, let’s assume that only 75% of the adult population actively drives (to account for retirees, remote workers, etc.), which results in:
Estimated daily drivers or riders: ~163,125
Now estimate daily trip volume:
Assume 3 car trips/day per person (commute, errands, drop-offs), a conservative figure
Total passenger trips: 163,125 × 3 = 489,375
Assume average car occupancy = 1.5 people
Estimated daily vehicle trips = 489,375 ÷ 1.5 = ~326,250 car trips per day generated on the West Side
This is far beyond the 66,000 vehicle trips/day claimed by SFMTA for 19th Avenue, and it only accounts for residents — not through-commuters, commercial vehicles, or visitors.
Thank You, Aaron.
I have read this analysis intently, and have nothing to suggest, other than for all persons to carefully assess the relative utility of their location and transport choices in this world of gradually constricting options.
;-(