I have a very basic game idea someone is welcome to, would work great for touch devices.
Top-down View of streets with traffic lights at every intersection and a parking garage. The cars all move at the same speed and the player must tap the traffic lights to direct the flow of cars and get them all into the parking garage.
The streets are all single lane streets, but not one way.
The traffic lights have four modes: Stop, Go, Left Turn, Right Turn
Additional mechanic concepts:
-The player may tap and hold on a traffic light and select a traffic cop to clear traffic jams automatically. Maybe only three traffic cops per scenario.
-Difficulty can be increased by changing the cars speed limit, by making the cars pass a check point before going to the parking garage or reducing the number of entrances into the parking garage.
Hope someone finds this useful.