the Governor of Delware with his '29 Cadillac, and license plate #1, on a "Weaver brake tester" that used drive-over plates and liquid gauges to instantly show each wheel's braking power simply by driving the car on at steady speed then jumping on the brake pedal.

https://forums.aaca.org/topic/341211-period-images-to-relieve-some-of-the-stress/page/602

https://www.oldclassiccar.co.uk/weaver.htm