“Too often, speed traps are difficult to avoid.”
Only if you are speeding.
In many cities, there is a sudden drop in speed limits upon entering the town, sometimes at the bottom of a hill (there was a trap like this in Esteline, Texas that was notorious). Although state laws often provide a distance at which you may achieve the lower speed, these distances are often not observed by police officers, knowing that in most cases, the driver will shut up, sign the ticket, and pay the fine. At other times, stop lights are deliberately short signaled from yellow to red. There are numerous other ways laws are manipulated to catch unsuspecting drivers. Additionally, some speed limits are established for reasons other than engineering or safety. For example, in the Houston and DFW areas, speed limits were dropped on freeways by 5-10 mph because of air pollution concerns, even though the data supporting the benefits of the drop were dubious. And can we forget the national 55 mph speed limit imposed on the country in 1973, partially lifted by Reagan and finally removed by Clinton (at the insistence of a Republican Congress) in 1995? That was perhaps the most widely flouted law since Prohibition.
I would have less objection to traffic laws if they were objectively arrived at and not driven by various agendas, whether greed, nanny statism, or pressure from the insurance lobby.