When was the first car radio installed in a car?

Maybe not the first radio, but an interesting story:

Radio's were first in homes and someone found a way to put a radio in a car. Actually 2 brothers in the 1910 worlds fair parked a car in front of the exhibit hall with a working car radio that they designed and installed. They called their invention a "Motor-ola", in reference to the "Vic-trola's" or record players people had in their houses. Everyone was excited with the new invention that was in the vehicle. Eventually the two brothers formed a company called ------- "Motor-ola" (which evolved into the corporation we know today as Motorola). True tale.