https://en.wikipedia.org/wiki/Daytime_running_light https://en.wikipedia.org/wiki/Daytime_running_light For a car that has DRL enabled, you’ll be able to tell

https://en.wikipedia.org/wiki/Daytime_running_light https://en.wikipedia.org/wiki/Daytime_running_light For a car that has DRL enabled, you’ll be able to tell that the car’s engine is running by checking to see if head lamps are on. It’s especially useful check for (stationary) cars during the day when you are at a distance where the engine’s sound is inaudible.