ladamic's blog research on information networks and non-researchy random musings


Caltrans district 4 bike survey maps

Filed under: data fun — ladamic @ 20:03

Earlier this year Caltrans conducted a survey, where you could drop “pins” on a map and specify examples of good bike infrastructure, where there are barriers to biking, and where new or improved bike routes are desired (all this on state-owned/maintained roads).

3,400 people took the survey, and dropped 20,000 such pins. The survey report contained many interesting insights, but still I was a bit disappointed that the output was not as interactive as the input. The included heat maps seemed too coarse to distinguish particular roads (except potentially some bridges):

Caltrans had shared the survey data along with the report*. When I asked around how one might re-construct interactive maps from it, my colleague Andi Gros suggested I try leaflet in R.

I did! So now you can see individual roads, pan and zoom thanks to OpenStreetMaps. 

There are also the individual comments people pinned to the map. There were just too many to plot together interactively without making my browser unhappy. 

So instead I attempted separate maps for

  1. Examples of good infra (The Stevens Creek Trail features rather prominently!)
  2. Barriers to biking (south of SF only), you can also attempt to load a map with all the comments.
  3. Places where new and improved bike infrastructure is desired, again you can try all the comments too.
  4. (circles only) Roads people would like to travel along or cross

So this Thanksgiving I am grateful for bikes, for people who bike, for Caltrans caring that there are people who bike, but most of all that we can have a sense of humor about transportation infrastructure.



* As a survey taker I wasn’t necessarily anticipating that the data would be available for download (I tend to not read instructions). But the comments I think are great to read and share. Do let me know if you find anything that should not be there. Thanks.

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