Why 10mph over the speed limit is ok... only 2X the chance of a crash

Statistics tell us that at 10 MPH over the posted speed limit, the probability of being involved in a crash doubles. However, at 20 MPH over, the probability increases to 11 times greater. We are trying to change the driving behavior of those persons who are most likely to cause crashes."

- Scottsdale, AZ police department on why speeders are allowed an 11mph buffer.

<a href="http://www.scottsdaleaz.gov/photoradar/faq.asp#11mph">http://www.scottsdaleaz.gov/photoradar/faq.asp#11mph</a>;