Where does the crash data come from?

Oregon motorists must notify the state Driver and Motor Vehicle Services division whenever they’re in an accident that causes injury or more than $1,500 in property damage. The DMV also gets the results of police investigations. ODOT analysts review the documents and decide what caused each crash.

Because cyclists do not file accident reports — and because police reports are available in only one-third of all crashes — ODOT usually sees only the driver’s version of events. But in 249 bike crashes investigated by police from 2003 to 2006, ODOT pinned primary responsibility on drivers 50 percent of the time, cyclists 42 percent, and both parties 8 percent.

Descriptions of accidents in this map came from the ODOT database, except when additional information was available from the archives of The Oregonian.