Vision Zero - Speed Limits

Speed Limits

Vision Zero suggests the following "possible long term maximum travel speeds related to the infrastructure, given best practice in vehicle design and 100% restraint use". These speeds are based on human and automobile limits. For example, the human tolerance for a pedestrian hit by a well-designed car is approximately 30 km/h. If a higher speed in urban areas is desired, the option is to separate pedestrian crossings from the traffic. If not, pedestrian crossings, or zones (or vehicles), must be designed to generate speeds of a maximum of 30 km/h. Similarly, the inherent safety of well-designed cars can be anticipated to be a maximum of 70 km/h in frontal impacts, and 50 km/h in side impacts. Speeds over 100 km/h can be tolerated if the infrastructure is designed to prevent frontal and side impacts.

"Roads with no possibility of a side impact or frontal impact" are sometimes designated as Type 1 ( motorways/freeways/Autobahns ), Type 2 ("2+2 roads") or Type 3 ("2+1 roads"). These roadways have crash barriers separating opposing traffic, limited access, grade separation and prohibitions on slower and more vulnerable road users. Undivided rural roads can be quite dangerous even with speed limits that appear low by comparison. For example, in 2008, Germany's 100 km/h (62 mph)-limited rural roads had a fatality rate of 9.5 deaths per billion travel-km, over four times higher than the autobahn rate of 2.2 deaths. Autobahns accounted for 33% of German road travel in 2008, but just 11% (495 of 4,477) of traffic deaths.