Comaps can display your current speed and (if it's in the data) the speed limit for the road you're on - everything you need to avoid speeding tickets!
Put this in another comment, but social conventions for driving vary a lot by region... in the US at least. Can't speak for anywhere else. In Chicago, if you're driving the speed limit on an interstate, people just assume you're geriatric or stoned. The flow of traffic is consistently 10-15 over on all Chicago area interstates. Cops do 20 over. But, in the Bay, unimpeded flow tends to rest at 0-5 over.
As someone who isn't a speed demon, I still like the police warnings because it's a timely reminder to check myself. Am I matching the flow of traffic? Do I blend in? Am I making myself a target?
It would be really cool to see the social situational awareness sharing feature be implemented in an open client over an open censorship resistant protocol. Because to me Google maps is just mass surveillance by the pigs even if it does happen to help you today, the long term incentive for big tech is to erode user freedom and collude with corrupt governments.
This is a nice feature, I'll give you that, especially when you're in a new place. Social conventions of driving vary a lot, and "hey there's a cop ahead" is a good reminder to check yourself.
I'm no speed demon (it's just not worth it IMO). But, in Chicago you can do 10-15 over on an interstate and nobody cares. The cops are doing 20 over. If I saw someone actually doing 55 on the Dan Ryan I just assumed they were stoned, and I'm only half-joking. Elsewhere around the Great Lakes, it was more like 5-10 over. Meanwhile, in the Bay Area the flow of unimpeded traffic is usually only 0-5 over.