It's national "don't run red lights week" (who knew?) and yesterday we learned 3.4 percent of traffic crashes in Ann Arbor between 2007 and 2009 were caused by a driver failing to stop on red.

Although that translates into 94 crashes, the percentage is still relatively small when considering the total number of crashes in the area. Countywide, a total of 580 red-light related crashes occurred from 2007-2009.

So what causes most crashes?

Car_crash.jpg

Many crashes are caused when drivers fail to stop in an assured distance.

Eric Bombery, a transportation planner with the Washtenaw Area Transportation Study, crunched the data for the hazardous actions that cause crashes. He cautioned that the figures represent drivers and not just crashes since there can be multiple drivers in a crash.

These categories represent the hazardous actions police note in crash reports - they don't delve into the causes of the actions, such as distracted driving (no more texting behind the wheel).

Not surprisingly, driving too fast, failing to yield and the inability to stop in an assured distance were factors in many crashes (not too many accidents resulting from driving too slow).

The following chart breaks down those hazardous actions when noted (some are unknown or weren't coded on accident reports).

Driver Hazardous Action 2007-2009   
 200920082007
None809882128876
Speed too fast147918871604
Speed too slow183122
Failed to yield145514831598
Disregard traffic control244270317
Drove wrong way122117
Drove left of center10310590
Improper passing9385107
Improper lane use335376394
Improper turn160200192
Improper / no signal173117
Improper backing266256291
Unable to stop in assured clear distance264927053067
Other569565631
Unknown342311337
Reckless driving9388106
Careless / negligent driving351389440
Uncoded & errors548704658