Primary Data Sources

Friday, February 24 2012

✔ City of Tucson,

Run by the City of Tucson and funded by a grant from the Pima Association of Governments (PAG), provides a variety of transportation-related information. In particular, they maintain a list of active traffic incidents as dispatched by the Tucson Police Department and the Pima County Sheriff's Department.

The list is at An automated process scans this page and saves the results to a database (not the bikecolli database, a different one). Collisions mentioning “bike”, “bicycle” or “pedestrian” are flagged for further interest. In 2010, Tucson Bike Lawyer Erik Ryberg wrote about this and called it a “robot.”

✔ Tucson Police Department, Crime Statistics Database

This is the records division of the Tucson Police Department. Don't be fooled by “Crime” in the title, the Crime Statistics Database references all manner of paperwork including criminal reports (murders, robberies and assaults), noise complaints, traffic collisions, all the way down to malfunctioning traffic lights.

For traffic collisions, the crime statistics database returns only the barest of information. It shows the date, the street, the nearest police substation and the UCR Code. This is not enough to place a collision on a map. However, using a different facet of the crime stats database, it’s possible to look up traffic collisions by cross street to confirm the nearest intersection and time.

✔ Combining and Cross Referencing

Of course the Transview and TPD data overlap by a significant amount, and two collision records at (or near) the same intersection in the same time frame are probably referring to the same collision. Because the Transview data represents where the officers were dispatched, and the TPD data usually represents where the crash actually happened, some duplicates do creep in.

✔ Adding Police Reports

Bicycle-related police and sheriff’s reports come through the Tucson-Pima County Bicycle Advisory Committee (TPCBAC). The police reports allow us to remove the duplicates, set the crash locations with reasonable accuracy and allow access to all the interesting data beyond simple place and time — collision types, fault assessments, cyclist/motorist behaviors and demographics.

Bicycle Crash Data
Crash Statistics
Cyclist Statistics
Motorist Statistics