The general rule when it comes to bike lanes is that, if you build them without some sort of grade-separation, at some point a car is going to park in them. But here are two possible solutions to this problem. The first is that you could build some sort of grade-separation that can't be driven over. And the second is as follows:

Now a New York City Council member is pushing a bill that would give civilians the power to report bike lane scofflaws, as well as vehicles that block entrances or exits of school buildings, sidewalks and crosswalks. New Yorkers who submit evidence of a parking violation can earn 25% of a proposed $175 ticket. The Department of Transportation would review the evidence to determine whether an infraction has occurred, according to the bill’s text.

What this essentially does is decentralize rule enforcement by paying people to be rats. Off hand, I can't think of any other cities that have done something like this and so I don't know how effective it might actually be. But being a rat sounds like it could be a good paying job.

Let's assume that somebody decided to treat this as their full-time job and work 8 hours a day, Monday to Friday. And then let's assume that they were able to rat out one person per hour. Here's how much money they could make in a year:

• $175 x 25% = $43.75 per illegal incident

• $43.75 x 8 incidents per day = $350 per day

• $350 per day x 5 days a week = $1,750 per week

• $1,750 per week x 52 weeks = $91,000 per year

Now, if the goal of this rat-people-out program is to ultimately change behaviors, then it might make sense to assume that your revenues would decline over time as more people start following the rules. Either way, something tells me that more than a few people would be happy to take on this job.