Friday, August 27, 2010

Why You Should Care About Curb Radii

I know, "Curb radii?!" You must be wondering why I've decided to put you to sleep, but hear me out.

First I have to explain what a curb radius is. Imagine the corner of a block. It's rounded, but imagine it were a right angle with each curb extending to a point of intersection. Now hold the location of that point in your mind and visualize the real rounded corner. The curb radius is the distance from that imaginary point to the point at which the curb starts to curve. Got it? Here's a picture (it's the distance from B to A):


This is important because large curb radii mean cars can take the turn faster and pedestrians have farther to cross in an intersection. Therefore, large curb radii and the gradual curves they imply are bad for pedestrian safety and convenience.

The shorter the curb radius, the sharper the turn, and the more cars have to slow down and pay attention when they turn. So, support small curb radii!


  1. Chewie: I always hear that large radii are needed for the large trucks and firetrucks to make their turns. How do I respond to this?

  2. @ Rob,

    It's true to some extent that large vehicles need the larger radii. However, if they are turning onto a street that has multiple lanes, they can make a right turn by swooping into a far lane. Rolled curbs can also allow the passage of emergency vehicles around tight corners while restricting the flow of normal vehicles.

    I'd say the best way to respond is to push for the smallest radius that accommodates emergency vehicles given the situation.