Good idea, paid subscription
The idea is not bad, but who is going to pay subscription fee for this? It is a just a gimmick. Mapping apps show you speed limit for free. My car shows me a speed limit. If you managed to get time to red, good, that’s a nice little feature. Besides, you want location access ALL THE TIME, and you want my personal information? So it tracks me even if you are not driving. No thank you! Change location to only while running. Even that is too much. And don’t ask for any personal data. Removing the app, but giving you an extra star for a good idea. Keep working on it, and get the cities from whom you get the data feed to pay you. They benefit by having reduced traffic congestion. Users won’t benefit from it for a while.