Speed limits are arbitrary but, arbitrary by need. In most cases the speed limits are set on roadway by the recommendations of engineers and other officials based on several factors.
The first factor is condition. The condition of the road is important because if you have a roadway that is not in the best of condition or is known to freeze, flood, hold water, dip etc., then these are conditions that with extreme speeds could be a hazard to the driver of the vehicle or other on the roadway.
Another factor is location. It is important when considering a speed limit for a roadway you consider what is around the roadway, what type of area does the roadway pass through. Is it in a school zone, a residential neighborhood, a business district or in the middle of nowhere. I don’t know about you but I would hate to see a vehicle driver 70 mph in front of my home. Even if your children don’t run in the street what happens if there is an accident and the cars come flying off the road.
The third factor that is considered is grade and turns. With winding roads and hills it is really hard to have a high speed limit. Based on the turns and the hills the speed limits on roads like this are adjusted accordingly.
Speed limits are a safety issue for the simple fact that if you don’t have speed limits then you will have a lot more people than you already do out there driving like maniacs. It is sad to say that you have to tell people what is safe and what is not safe because not everyone has the sense to know better.
Enforcement of speed limits is not solely to generate money. Though they do generate money law enforcement agencies are only able to use a percentage of the money raised regardless of how much they raise from traffic citations. If it wasn’t for enforcement then the speed limits signs would be useless. People learn from making mistakes and paying for those mistakes. People die daily from high speed driving. I don’t know about you but I would much rather get into a car accident with someone going 35 mph than I would at 70 mph.
So arbitrary maybe, but there is most surely a need to establish safe speed limits for the greater good of the public at large.