Prototype

This is fairly easy, but will take about 10-15 minutes. This has to be done without getting out of your tank; if you get out or your tank is destroyed, the count resets. Once you have learned how to drive tanks and APCs, steal one and then just drive around the city running over civilians. It helps to just keep driving over sidewalks as most of the civilians will be on them. Try to stay in the normal areas of the city so you only run over civilians. If you go into the military zones, you run the risk of running over military personnel and triggering an alert and possibly having your tank destroyed. If you go into the infected zones, you also run the risk of running over military personnel, and you also run the risk of having some Hunters follow you. Because of this, it is easier to do this trophy either right after you've learned how to drive APCs and tanks, or after the story in Free Roam mode.

You can track your progress under the Statistics -> Kills page on the pause menu, but please note that this counts all total Speed Bumps, so make note of how many you already had when you start you run for the trophy.