3 relatively highly rated games all free now off the Google Play Store. Thanks @gentlecrack for the iOS links.
iOS links seem to have expired, Google Play store variants are still free.
Traffix: Traffic Simulator
Control the traffic flow. Decide when the cars can pass and avoid crashes. Traffix is a minimalist traffic management game where you need to manage the traffic flow by turning on/off the traffic lights.
Railways - Train Simulator
Do you have a refined taste for train simulator games? Railways is a simulation game where you have trains, passengers and railways. Your goal is to manage the trains strategically between the tracks, picking up the passengers and preventing crashes. Your mission is complete when you collect all the passengers.
Package Inc - Cargo Simulator
Package Inc. is a beautiful game about building a delivery system for a growing city. Build a connection between different hubs and feed multiple destinations, like factories, police stations, cafes, libraries, boutiques, saloons, hotels, pizzerias, pet shops or schools.