User blog comment:Mr Procrastinator/Length of Drag Races/@comment-26249703-20160217160349/@comment-26329136-20160217170652

To record the data, I simply entered a drag race, remained stationary at the start line, wait for the opponent to cross the finish line and note how far ahead the opponent is. Once the opponent crosses the finish line, the distance stops increasing.

Spa can be found in Hot Hatch Power Match (Event 13.2) and Le Mans can be found in Race-Spec Maserati Granturismo (Event 4.2).

Concept Car Clash has a Silverstone, International Circuit drag race and a Porsche Test Track, On-road Circuit (Long) drag race but I haven't unlocked them yet.

I think these are the only drag races appearing in only one series.