To help your team use this to kill the cars:
If you know one is coming, both by the announcement and the sound of the car itself, place yourself in a protected area. Such as an area that your team controls. Remain visible at short range only to avoid snipers. Throw the counter measures mine at your feet and stay within its radius. Get the car see you so it will try and get you. Maybe move away from the mine, wait for the car to start following you, then move back. Maybe shoot at it to get its attention. The cars are mighty fast so dont go too far away. The goal is to not just protect yourself but to lure it in, kill it, and protect your team. Then pick the mine back up and move on. Remember there is a 30 second recharge time. For added protection get Hardwired so you dont get affected by your own mine and to allow more freedom of movement since it cannot blow itself up.
Voila no more car. Saved me from five cars in one match today. And more importantly, saved my teammates from them. Yes I designed it with this in mind.