Story behind Mental Speed Bumps

I made an accidental discovery in 1996 that turned everything I believed about streets and calming traffic upside down. I was working with a neighborhood in Brisbane on designing a new kind of Traffic Calming. As part of the design process we held a giant street party. A short time after the street party residents reported to me that the traffic was going slower in their street. ‘It can't be' I replied in disbelief. ‘We haven't made any changes to your street yet.' Like everyone else I assumed that the only way to get drivers to slow down was to change the design of the street and force motorists into slowing down. But I investigated and the residents were right. Traffic was going slower.

The reason?

Prior to the street party many residents and kids did not know each other. At the street party new friendships were formed and we legitimized the street as socializing space. As a result, after the street party more kids played together on the sidewalk and more adults socialized in the street. Motorists were slowing down because they were unsure what the kids may do or they wanted to have a sticky beak at the adults socializing in the street.

As a result of this accidental discovery, I began running experiments in neighborhoods all over the world, refining techniques for creating mental speed bumps that slowed drivers, without the driver even being aware that they had been slowed.

Some years later my daughter rang me to tell me that some man on TV had stolen all my ideas. It turned out that a Dutch engineer, Hans Monderman, had also made the same accidental discovery. However, Hans was creating mental speed bumps in a different way to me, although they employed exactly the same underlying principals. Hans was removing all the traffic control devices from streets; speed humps, white lines, signs and traffic lights (what some call the naked street approach).

Mental Speed Bumps takes you behind the scenes of this remarkable story of a accidental yet simultaneous discovery. Importantly it gives everyone, from residents to city officials, practical guidelines on how mental speed bumps can be used to calm traffic across the entire city.

AU$29.95 (about US$23)

David Engwicht is one of the world's most innovative urban thinkers and is inventor of the Walking School Bus.

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