I recently had a suspect drive off while I was approaching the vehicle on a traffic stop.
As I ran back to my patrol unit, I lost sight of the fleeing suspect vehicle. What I have incorporated into my routine during traffic stops (especially on graveyard) is to tell the driver to turn off his/her vehicle prior to my approach. That gives me a chance to assess the driver and in case he/she wants to take off, I can quickly jump in the driver’s seat and chase if I have to.
If the driver can’t hear me, I use the microphone or signal with my hand to turn off the car.