There are numerous accounts of motorists escaping responsibility for their violating traffic laws which result in injuries and deaths of cyclists. Googling "police refuse cite motorist bicycle" will provide the needed examples across the U.S. After reading a few dozen accounts, the general scenario seems to be:
A motorist either unknowingly or deliberately violates the law
The violation results in the injury or death of a cyclist
The responding police officer makes an on-scene decision to not cite the motorist
Appeals for justice either fail inexplicably or due to lack of evidence.
I think it is safe to assume that not all of these sources are unbiased and accurately representing all the facts. I have first hand knowledge of police officers taking great exception to motorists' bad behavior around cyclists and their concern for cyclists' safety even when those cyclists break the rules of the road. Additionally, it can be remarkably unfair when critics use the benefit of 20/20 hindsight to question decisions made by police officers based on facts available at the time.
All that said, the number of the reports and their similarity have me speculating on what might be motivating a small number of well-trained good intentioned police officers to effectively look the other way then motorists' illegal behaviors result in the injuries and deaths of cyclists.
Could it be that some police officers are blaming cyclists for their own injuries and deaths? I just don't see an alternative explanation that makes sense to me. Their thinking might very well be that persons choosing a bicycle over a car are knowingly placing themselves in such a hazardous situation that motorist are reduced to unwitting participants in accidents involving cyclists.
So why are roads actually and/or perceived as hazardous to cyclists? There are the obvious situations like narrow two lane roads and bridges heavily traveled by cars and trucks at high speeds. However, I avoid roads that put me at high risk and I still manage to have close-calls with motorists just about every time I ride my bike. When I say "close call" its means one or a combination of the following:
I am forced to take evasive action to avoid being struck by a motor vehicle
Motor vehicles when passing me risk head-on collision with oncoming traffic
Motor vehicles passing well within 3 feet of me; especially large vehicles at high speed
Motorists using aggressive driving or other bad behaviors to force a response from me
This frequent bad behavior of motorists leads me to believe that states are licensing a number of motorists that are lacking the minimum skills, knowledge, judgment, attentiveness, and temperament to safely drive multi-ton high-speed vehicles in mixed traffic. Most concerning is this has serious ramifications for the effectiveness of new and proposed laws intended to improve the safety of cyclists sharing the roads with motor vehicles.
The state by allowing ignorant, inattentive, incompetent, and ill-tempered persons to obtain and keep their licenses sets law enforcement's low expectations of driver performance in mixed traffic. In short this is, in my opinion, the root-cause of the perception amongst some in law enforcement that holding motorist to the higher standard of behavior required to keep cyclists safe is unfair to motorists.
The new laws passed like the 3 ft rule and others being proposed to protect cyclist are overdue, but to be effective people licensed to drive must be willing and able to following them. Until then the defense of "too ignorant or too ill-tempered to drive safely amongst cyclists" will continue to be a source of road-side pardons for motorists injuring and killing cyclists.