The first car races were run under a sort of rally format. Circa 1895, races were on open public roads. To keep the cars separated, they were started with a time interval between each car. Sometimes as much as half an hour or more. The first rally was the Monte Carlo in 1911 IIRC. The hoteliers of Monte Carlo wanted more business in the winter and you had to be rich to own a car then. So a chamber of commerce type dreamed up having car owners rally, meaning gather together, from several cities in Europe.
So for your research on the very beginnings, start with racing and then with the history of the Monte.