Trivial or concocted traffic law violations are frequently used as an excuse to stop, detain, and search persons for whom the police have no otherwise legitimate reason to do so. "Probable cause" or "reasonable suspicion" are inserted after the fact and only if the motorist lodges a formal complaint.
A large proportion of the stop signs erected by local governments are illegal and in violation of state traffic regulations. They know that people don't stop for them since the intention is to use the signs as speed control devices. This proliferation of stop signs merely increases the number of motorists who can be cited for failing to stop when there is no reason to.
The best protection against the "good ole boy" system where the judge, district attorney and the arresting officer are on a first-name basis is the jury trial. Jury trials are time-consuming, expensive, and diminish the profitability of the traffic ticket system. Therefore, state-by-state, the right to a jury trial is being incrementally denied to traffic ticket defendants, all under the guise of being more fair when actually it is less.
Only a small fraction (about 2%) of all traffic tickets are seriously contested. The vast majority of these contested tickets are dismissed or the defendant is given a significantly reduced penalty. If just 10% of the people who received citations fought their tickets, the entire system of government extortion would collapse within a matter of months.