Driving in traffic on two lane, busy state highway at 55MPH the engine stalled without warning. I started pulling over to the shoulder of the road while trying to process what happened. To restart the engine required me to place the automatic transmission in neutral and press the keyless stop/start button. Someone driving the vehicle besides myself may panic and place the gear selector in the wrong position thereby causing an accident at highway speeds. Had this happened in a busy intersection it may caused a collision. Luckily the engine restarted and was able to proceed without incident.