Detecting vehicles is a project by itself, so here we will focus on what we already have and that is an Inductive Loop Vehicle Detector (ILVD or ILD). Simply detecting vehicles is not enough because we somehow need an information whether vehicle is parked/stopped and not moving, because once the vehicle starts moving we need to stop reminding the driver about the green light as he/she obviously got that information.

We can do this with an additional functionality of some better ILDs on the market that detect stopped/parked vehicles or we could build one our self (https://www.elektronika.ba/868/dual-channel-inductive-loop-vehicle-detector/). So lets start experimenting...