As someone who's done this type research, it's highly cherry picked and riddled with conflicted interests. It also encourages unpredictable driver behavior, which goes against the basic principles of right-of-way. You want drivers to be as predictable as possible for the benefit of drivers around them.

This is in addition to philosophical arguments against:

contest/court fees that are higher than the fine for pleading guilty,

The entire idea that criminal police enforcement can be contracted out,

Or, if civil enforcement, the idea that speeding in-and-of-itself is a justicable suit. Ie, the idea that the city suffered damages by someone speeding, and that an arbitrary fine is the appropriate remedy.

Get rid of companies collecting a rake, as well as the cities keeping the fines, and suddenly no one is fighting for the programs anymore.

>>to eliminate cars in urban areas

Hope to live to see this utopia. In the meantime, I'll take it if public money is invested in traffic calming - this might deter some driving at least, and definitely will make it safer. Also serves as an indicator that the place is not "car-first".