Why do NASCAR races always start while going (after the pace car leaves)?
NASCAR uses the rolling start method and always have. Reason being is that there would be a huge wreck at every race if they had a standing start.
You can't grid the cars up on the banking. The banking is much taller and steeper than it appears on TV or from the grandstands. A stalled car on the grid would cause instant problems at short tracks with the leaders coming around almost immediately. Tradition
I really don't know but TRADITIONALLY NASCAR has always had rolling starts. I think this is a wee bit safer? No mass pile-up? Whether relevant or not, F1 tracks are not just ovals or level..
Could be as simple as tradition. NASCAR has always used rolling starts vs standing starts. The NASCAR race cars are also not the easiest things to control with a standing start.
No speedometer in the car so the pace car is used to tack how face pit road seed is.