Friday, April 10, 2015

How 15 mph Makes a Difference

I've written before about how critical slower speeds are to pedestrian safety, and this week has a great post that pulls together a lot of important information about vehicle speed and safety. I especially liked this graphic that shows the difference between what a driver traveling at 30 mph sees vs what a driver traveling at 15 mph sees.
Notice how all the pedestrians on the sidewalk disappear at the higher speed. As Bill Lindeke writes in the post,
"If you look at the average speed of traffic on a urban commercial streets, there are a lot of things that begin to change when you slow down cars from the 30 to 35 mile per hour range into the 20 to 25 mile per hour range. Most importantly, perception, reaction time, and crash outcomes are far better at 20 than at 30 mph, while traffic flow doesn’t seem to change very much."
Even thought risk of death and injury is dramatically higher when vehicle speeds exceed 20 mph, most local roads (especially older ones like those in my neighborhood) are designed to encourage much greater speeds. Until we address this problem (admittedly a challenge, given the cost of retrofitting roads to narrow them) speeding and the dangers it presents will continue to be a problem for pedestrians. 

No comments:

Post a Comment