Maps/Waze can also shape traffic by suggesting different routes. One interesting half-way-there solution (and this is a technical solution involving cars, not

Maps/Waze can also shape traffic by suggesting different routes. One interesting half-way-there solution (and this is a technical solution involving cars, not reducing them as I'd much prefer) would be to have nav apps be able to read the traffic light timings for the intended route, and give you a suggested speed to travel at to maximise green lights and/or traffic throughput. It would piss off cars that want to go exactly at the speed limit, but would probably end up getting them to their destination faster. In both cases, cities could offer incentive schemes (e.g. points -> $ or discounts off licence/registration fees) to encourage people to 'follow the computer'. Would probably be cheaper than building infrastructure.