Monday, September 28, 2009

A hump, a bump, or a lump

Readers of the Sacramento Bee will hopefully forgive me today as I have liberally quoted from Tony Bizjak's "Back Seat Driver" column of September 28, 2009. The column relates to my previous post describing the Traffic Calming effect of certain asphalt constructs. The fact that you sometimes see signs warning of speed bumps, speed humps, makes one wonder if there is a system to it all. According to Tony's sources, there is indeed a system:
Herewith, a primer, so you can amaze your friends:

All are undulations, but each has its own special task. Speed bumps are the tall, narrow ones in parking lots that rise abruptly, forcing cars to go really slowly. Speed humps are the more gradual undulations, about 3 inches high, that you find on many residential streets. If you see a warning sign saying "undulations," it usually means there is a set of two speed humps ahead.

Speed lumps are a variation on humps. They're the ones that have small sections cut out to match the axle length for most fire trucks (and buses) so those vehicles don't have to slow much on emergency calls.

Then there are speed tables, which are about 3 inches high, like humps, but with a flat top that's about 10 yards long. It's for slightly bigger streets than residential, and allows you to go about 30 mph, but starts jolting you if you go faster than that.

Humps, bumps, lumps. It caused midtown business association exec Rob Kerth to once ask: Should we start calling potholes "dumps?"

Thanks, Tony, we will all sleep better knowing the difference between lumps and humps and bumps.


  1. Thanks for the info Arnold. I assume that all of the above are considered as being "traffic calming devices." They may "calm" the traffic, but certainly "jar" the body and the car. I usually encounter them while walking and seldom even notice them.

  2. Nice blog, really I impress for your blog. I got more information about Speed humps . This type of speed humps are very urgent for all drivers.