RE: Road Rules and jerks.....
March 5, 2019 at 8:12 pm
(This post was last modified: March 5, 2019 at 8:13 pm by GrandizerII.)
(March 3, 2019 at 8:04 pm)Jörmungandr Wrote:Quote:"They drive too fast" is the cry of many citizens when discussing how people drive on Interstate 81. At times this refrain is directed to the trucking industry and at other times to drivers in general.Consequently, some people have suggested the speed limit should be lowered to 55miles per hour on I-81.
However, research shows that faster travel is not necessarily associated with an increased risk of being involved in a crash.
When vehicles travel at the same speed in the same direction – even high speeds, as on interstates – they are not passing one another and cannot collide as long as they maintain the same speed.
Conversely, when vehicles are traveling at different rates of speed, the frequency of crashes increases, especially crashes involving more than one vehicle. The key factor is speed variance. The greater the speed variance, or the distribution of speeds, the greater the number of interactions among vehicles. Thus, passing maneuvers and opportunities for collision increase. Speed variance, not necessarily high speed, is associated with an increase in the frequency of crashes.
Interstate highways in Virginia such as I-81 generally are designed to accommodate traffic traveling 70 mph. This is called the design speed. Typically, people drive at or near the design speed because it is comfortable for them. When speed limits are set substantially below the design speed, research and experience show that most drivers will exceed the posted speed limit. In fact, before the rural interstate speed limit was raised to 65 mph in1988, the majority of vehicles were traveling faster than the posted 55 mph.
Research also shows that when the speed limit is below the design speed, there is an increase in speed variance, which is associated with a higher risk of crashes. Vehicles at either end of this speed distribution – the slowest drivers and the fastest drivers – are more likely to be involved in crashes.
Virginia DOT || Variance in Speed, Not the Speed Limit, Poses Greatest Risk on Interstate Roads
Regarding the last two paragraphs of that study: this indeed has been a bit of a nuisance for me. There are some road segments here I drive on that have a speed limit of, say, 60 kph but the segment itself feels like it should be a 70-80 kph instead.
