the Governor of Delaware with his '29 Studebaker President Eight, 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. (thank you CoSC!)

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

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

CoSC left me this terrific trivia info in the comment section! 

The hierarchy in the way license plates once were allocated reflected late eighteenth century political thought in most states. New York allocated “1” to the governor and “2” to the lieutenant governor. 

State senators would also get low numbers, the state’s senior U.S. Senator, the junior U.S. Senator, and the Congressman is issued a plate also in the single digits. 

anything coveted and derived from official governmental action was leveraged into a reward for political support. So in the early part of the 20th century, that low-number license plates became a way for politicians to say “thank you” by conveying favored status to the holders of such single digit plates  Law enforcement was aware a motorist displaying a low-numbered plate was due preferential treatment.

https://www.automobiliaresource.com/license-plate-collecting/politics-and-low-number-license-plates-part-ii

https://forums.aaca.org/topic/341211-period-images-to-relieve-some-of-the-stress/page/402