Police in motion
Please allow a user to tag the highway patrol (Z) and set (Z) in the direction of traffic at (X + A) miles per hour, where X is the speed of traffic and A is an accelerator (+5mph, +10mph, etc) set by the user. This will approximate the location of Z (highway patrol) and if Z approaches a Waze user, an alarm will sound “Police approaching”. The location of Z will be recalculated once a user hits “like”... give or take a few seconds (times the speed of forward moving traffic). Should enough users hit an option “Not in site”, Z will be removed…probably because the cop has exited or has pulled over.
Revenue generation: When a user hits “like”, offer the option for them to make a donation ($1, $5, $100, etc), any amount that is far less than the speeding ticket they would have received.
This is needed both to more accurately identify where they are and to avoid false positives. People report police when they see them driving, which leads to false positives. This is the best suggestion for this I've seen, as it gives a good recommendation for how to actually do this. It's basically the same thing I came up with, to continually update it based on estimation of their location based on the speed limit and on new reports, until a certain amount of time elapses with no new reports. Biggest problem would be accounting for where the police are in relation to the second (and third, and so on) driver when they like the report, not to mention the initial reporting driver.
As for tips, neat idea, but I wonder if it would just add more complexity for something few people would actually use. I honestly doubt I would tip anyone, as my payment is all the things I report to warn other drivers. We all help each other, and our payment is everyone else helping us.