Driving a Mercedes-Benz W125 Rekordwagen, essentially a W125 with streamlined bodywork and a larger engine, Caracciola set a new average speed of for the flying kilometre and for the flying mile, speeds which remain to this day as some of the fastest ever achieved on public roads.
Caracciola je že leta 1935 postavil rekord 311,985 km/h, toda to sta izboljšala Auto Unionova dirkača Stuck in Rosemeyer.