Posted in Bike Accidents on October 12, 2018
San Francisco is widely considered one of the most bike-friendly cities in the nation, scoring high in both road safety and accessibility to the city’s diverse neighborhoods.
However, despite the city’s embrace of bicycling as a viable method of transportation, its compact intersections and frequently busy roads still make bicycle collisions a regular occurrence, with many leading to serious injury and even death.
We wanted to properly assess where bicycle collisions occur more frequently across the city, so we turned to data visualization firm 1Point21 Interactive for help. We analyzed five years of CHP crash data from 2013-2017 to pinpoint any hot spots of where cyclists are at risk of being struck by motor vehicles.
During the study period, there were over 3,000 motor vehicle collisions involving cyclists in San Francisco, leading to 17 fatalities and more than 2,700 injuries. Through our analysis, we identified the most dangerous areas, specific intersections, and neighborhoods for cyclists in San Francisco – based on crash volume and injury severity.
*Zoom and hover to reveal more detailed information for each zone. For best mobile experience, rotate device.
We conducted a kernel density analysis to identify clusters of high-crash activity within San Francisco – any zones with ten or more bicycle crashes within close proximity of one another.
In total, we found 24 high-crash zones accounting for 848 total bicycle collisions and 763 injuries.
Note: The Zone column is an approximate center area of each zone to allow readers to easily locate zones on our map. The zone may cover a larger or smaller area than described.
|Rank||Zone||Crashes||Severe Injuries||Visible Injuries||Total Injuries|
|2||Hayes Valley – Market St||135||6||52||122|
|3||Tenderloin – Polk St||82||6||32||76|
|4||Mission District – Valencia St||60||2||20||53|
|5||Haight-Ashbury – Divisadero St||46||4||26||45|
|6||Mission District – 14th St||36||5||12||34|
|7||SoMa – 8th Street||25||2||9||20|
|8||SoMa – Market Street||24||0||12||24|
|9||Fisherman’s Wharf – North Point St||21||0||9||20|
|10||Duboce Triangle – Church St & Market St||18||2||6||16|
|11||Tenderloin – Golden Gate Ave & Hyde St||18||0||8||15|
|12||Fillmore District – Webster St||17||2||4||17|
|14||SoMa – I-80||16||1||8||15|
|15||Nob Hill – Polk St||13||0||9||13|
|16||The Castro -17th St & Church St||12||2||6||12|
|17||SoMa- 13th St & Mission St||11||4||3||11|
|18||Mission District – Valencia St & 22nd St||11||2||4||8|
|19||Mission District – Mission St & Cesar Chavez||11||1||5||10|
|20||SoMa – 5th St & Howard St||11||0||3||8|
|21||Fisherman’s Wharf – Pier 39||10||3||3||10|
|22||Golden Gate Park||10||1||5||10|
|24||Mission District – Mission St & 17th St||10||1||2||9|
In total, we found 50 intersections where five or more bicycle crashes occurred within 150 feet. We then ranked them using our Bicycle Danger Index (BDI), a score that takes crash volume and injury severity into account.
|wdt_ID||Street Pair||crashes||injuries||complaint of pain||visible injuries||severe injuries||fatalities||Score|
|1||OCTAVIA ST & MARKET ST||20||18||7||10||1||0||95.00|
|2||VALENCIA ST & 14TH ST||15||14||6||7||2||0||80.00|
|3||MARKET ST & 5TH ST||17||15||11||7||0||0||79.50|
|4||MARKET ST & 2ND ST||13||12||3||9||0||0||65.50|
|5||MASONIC AV & FELL ST||11||12||5||3||3||0||61.00|
|6||MARKET ST & 7TH ST||15||11||10||4||0||0||60.00|
|7||POLK ST & ELLIS ST||11||10||4||5||1||0||53.50|
|8||MARKET ST & 3RD ST||7||10||4||1||4||0||52.00|
|9||CHURCH ST & 17TH ST||9||9||3||4||2||0||51.50|
|10||VALENCIA ST & 18TH ST||10||7||6||2||2||0||50.00|
Within this list, there were three intersections which had fatalities – one each:
When categorized by neighborhood, SoMa and the Mission District had by the highest amount of bicycle crashes, with 396 and 276 crashes respectively. This aligns with our intersection and zone data as well, as most problem areas are located within these two neighborhoods.
Other notable neighborhoods include Mission Dolores (144 crashes), Civic Center (131), the Tenderloin (125), the Financial District (101)and Union Square (96).
As the number of bicyclists rises, it is important to practice proper safety procedures on San Francisco’s busy roads.
As a motorist, it is highly recommended to:
As a cyclist, you must exercise extreme caution on the road.
Crash data comes from the California Highway Patrol’s Statewide Integrated Traffic Records System for the years 2013 – 2017. When geolocation data was not available, we geocoded records using cross street information. Records without cross street information were eliminated from our analysis.
High crash zones were identified using a Kernel Density Estimation and GIS software.
Dangerous intersections include all crashes that were marked intersection related or occurred within 150 of the cross streets provided. Our rankings were derived by applying our BDI formula to the results. Our BDI takes crash volume and injury severity into account. Fatalities, severe injuries and visible injuries are weighed heaviest in the index.