Prompt, please, cheap GPS trackers, to using Simcoe passed the location of the cars. Just need to see on the map where the cars are now (with a frequency of every 5-10 minutes), and, ideally, where they've been for the last 12 hours (at least).
Functions especially do not need any, let it be simple and cheap. The main thing - to not have to restart. To work let it be from battery cars themselves (but the built-in battery is welcome in principle, or any system from discharge of auto just in case).