Blue Skies Above Us

To Live and Ride in LA: Do Bike Lanes Make Angelenos Safer?

I recently completed my Master’s degree in Urban & Regional Planning from UCLA. Now I’m sharing my capstone project. This a research project I completed in my final year, with the Los Angeles County Bicycle Coalition (LACBC) as my client. The LACBC used some of the findings in their own report, the 2015 Bike Count Report. That link contains a nice synopsis of key findings, plus a link to download the whole report. The report is very digestible, with some great graphics. It shows the results of the 2015 bike count (I did the statistical analysis), as well as the results of my research on the safety impacts of newly-added bikeways in Los Angeles.

The two key findings are that bicycling has decreased since the last count (though it’s increased on bikeways), and that the new bikeways have made bicyclists safer.

I’ll admit that it was stressful to have to reveal to the LACBC that ridership was down. After all, one of their goals is to promote bicycling. But another one of their goals is improving safety (see Operation Firefly, for one). And so I believe the safety findings are important (and positive!).

My analysis measures changes in bicyclist-involved collisions as a function of ridership. This methodology, to be frank, makes it an exception among active transportation safety impact studies. Most seem to look at raw crash numbers, without accounting for ridership. A quick explanation for why this matters: if the number of crashes double after a bike lane is added, but ridership has quadrupled, then the rate of crashes has decreased (a simple analysis of raw crash numbers would state that crashes increased, even though safety per bicyclist had actually improved).

The bicyclist counts are conducted at discrete locations throughout Los Angeles. The counts take places every other year, and many sites are repeated each time. I identified all of the new bike lanes and sharrows in Los Angeles, and then narrowed them down to the ones with before/after counts. I found 17 sites that fit this criteria. I also included 18 control sites. The study finds that the rate of crashes per bicyclist declined by 43% after the installation of bikeways (there was no real difference between road diet, squeeze bike lanes, and sharrows). With respect to the control sites, ridership levels remained constant, while the number of crashes increased by 22%.

Read the entire report!

To Live and Ride in LA: Do Bike Lanes Make Angelenos Safer?

The report shows the detailed results for each study site. I’d love to hear feedback (not only comments about the results, but feedback on the methodology).


Los Angeles County Crashbot

The Fart Earth Society


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This Rotten Blossom album is dope.

What about you?

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Founded 2005. Over the years I've posted writing, comics, ringtones, and stuff about maps, bikes, programming, pinball. And I had a robust music blog mostly about '90s hardcore punk (category = music).