Trib: City Crash Statistics Faulty, Erroneous
Chock full of errors.
That’s essentially the takeaway from a Chicago Tribune story published Monday that reveals how unreliable Chicago crash data is or at the very least, has been.
The Tribune compared crash data for Chicago from the Illinois Department of Transportation against crash data from the City of Chicago itself.
In many cases, usually the most crucial areas of measurement, the two entities were at odds.
According to the Trib report, the root of the problem comes from errors in how crash reports are filed. The story says an IDOT audit of Chicago’s procedure shows 30% of crash reports filed by Chicago police officers were erroneous with 70% of the reports missing critical information.
The story points out some of the wild differences between the two reporting agencies. In 2006, the city reported only 63 traffic fatalities compared to 176 by IDOT for the same year–a 179% difference.
The trend went the other way for right angle crashes at traffic intersections with the city reporting 24,576 angle crashes versus 16,392 for 2006–a 150% differential.
There were similar discrepancies for pedestrian traffic deaths and serious injuries due to vehicle crashes.
The news story says the city had recognized these weaknesses in their crash data and has been working toward improving the reliability of its own data.
Perhaps not surprisingly, the Chicago City Council voted 33-14 to pass Chicago’s speed camera ordinance last week based on what looks like unreliable, error ridden crash statistics.
Here is the Tribune’s full story, “Chicago police crash reports are full of errors, study finds.”