Motorists who are cited for speeding often argue that limits are unrealistically low. Conversely, men and women who live near busy streets often argue that local speed limits are too high and, therefore, unsafe.
The auto experts at I-86 Truck & Auto Repair decided to explore this issue. We found that some common assumptions about speed limits weren't entirely accurate.
Here are some key findings:
- Reducing a posted speed limit doesn't necessarily cause car owners to slow down.
- Raising the legal limit 10 mph only increases actual traffic speed 3 mph.
- Germany—with autobahn sections where you can go as fast as you want—has a much lower rate of crash deaths than the US.
- Significantly lowering a speed limit can decrease safety due to an increase of dangerous driving behavior.
- Roads with a speed limit that reflects actual driving behavior have fewer accidents than roads with a wide variation in driver speeds.
- It can be just as dangerous to drive slower than the flow of traffic than faster than the flow of traffic.
- In the US, the traffic fatality rate has dropped despite the national trend of increased legal speed limits.
How Are Speed Limits Determined?
From 1973-1994 there was a 55 mph Federal speed limit in the US. This controlled speed limit maximums on interstate highways. The Federal speed limit was not set based on safety data, however, but in response to an energy crisis.
In 1995, Congress repealed the National Maximum Speed Limit. In the years since the repeal, 41 states have increased maximum speeds to 70 mph and above.
When traffic engineers recommend a speed limit for a specific road or highway, they determine the 85th percentile speed. This is the speed 85 percent of drivers maintain on the roadway. Other considerations include the physical aspects of the road and accident statistics.
Numerous studies point to the effectiveness of speed limits based on the 85th percentile rule. Those who trust it argue that the majority of drivers travel at a safe speed—regardless of the posted limit. The same studies suggest that it does not increase safety to lower a limit significantly from driving norms.
Thanks for visiting our blog. We invite you to rely on I-86 Truck & Auto Repair for quality auto maintenance and repair and wish you safe travels.