Speed limits
The speed limit on the straight desolate paved road that goes past our place is 80 km/hr. The people who use the road drive whatever speed they please and for the most part it works fine ….. until you...
Forum Discussion
Groover wrote:
Speed limits need to be set to what the police are really going to enforce. What is legal and what you can get away with should be the same thing, especially as self driving vehicles become more common.
The correct way to set the speed limit is to take the 85 percentile (speed at which 85% are going at or slower)...round to the nearest 5mph (10kph).
Enforcement is only effective going after outliers. And really the average driver does a pretty good job adjusting speed to what is appropriate to the roadway. The signs do almost nothing to lower the average speeds. A little effect on unfamiliar drivers but once or twice down a road and people drive what is reasonable.
The old slogan "speed kills" is more correctly written "differential speed kills". Ideally, you want everyone going the same speed so there is zero differential speed (you will never hit 100% but the lower the better). When you artificially, lower the speed limit, you have two groups of drivers, those who travel at a speed reasonable to the roadway (most drivers) and those who try to abide by the posted speed limit...that creates a higher differential speed and increased crashes.
Signed a Traffic Engineer who sets speed limits and studies crash patterns.
