I watched Ford vs
Ferrari recently, and also Elvis’s *Viva Las Vegas" and both feature a car race in which the cars are lined up here, the drivers are lined up there, and the starting gun is fired and the drivers sprint to their cars and start off.
Minor correction - it looks like the FIM Endurance World Championship still uses it for the Suzuka 8 Hours and the 24 Heures Motos races. But these are motorcycle races, not cars.
In the 1969 Le Mans race, Jacky Ickx famously did NOT run to his car, instead casually walked over to it and carefully and fully strapped himself in before heading out. Another driver, John Woolfe, who didn’t, promptly killed himself on the very first lap, and the next year everybody started the race already strapped in. Ickx won the 1969 race note.
My understanding is the LeMans-style start, with drivers sprinting across to their cars, jumping in, firing up, and roaring off became a thing of the past as a safety measure. Too many drivers were intent on ‘roaring off’ to get a lead, so they would strap in on the fly. The LeMans-style start also led to a great motorsports myth, that Porsche put the key switch on the left to make the start faster for their drivers. They could turn the key with their left hands, and operate the shifter with their right. All bogus, but it persisted for a long time.
The OP having received their answer, I wonder why that ever was a thing in the first place. Is it somehow more entertaining for those watching? Was there a perceived need to put more sport into motorsport? Was it somehow considered “more fair” instead of having a starting position determined in some other way?
LeMans was originally a competition for customer cars, or cars that you could buy and drive on the street. They had interiors, lights, turn signals, etc. Compared to F1 where you unbolted everything non-essential. As such, making your car difficult to get into was frowned upon, and starting outside the car was a way to enforce the spirit of the rules.
LMP cars today still have a passenger seat for that reason. It’s a joke of a seat, but it’s still there per the rules.