These cabs were made by the Yellow Cab Manufacturing Company of Chicago which was owned by John Hertz. The logo on the radiator looks almost exactly like the pin shown below. Another view of the cab is shown as well.

For Washington, D.C. to not require cabs to have true headlights in 1922, as compared to the cowl lights shown, seems strange. Most major municipalities, and certainly almost every state, had laws mandating required motor vehicle equipment by this time. Even worse, the cowl lights of Black & White Cab were not clear glass. Many also had the company name placed in them further reducing their ability to project light. An example of this is also shown below.

John Hertz is who Hertz Rental Car is named after, and the yellow Hertz logo harkens back to the days when he owned both Hertz and Yellow Cab.

The Pan American Union Building is on 17th Street NW between C Street NW and Constitution Avenue NW. It took almost two years to complete and was dedicated on April 26, 1910.

As founded by John Daniel Hertz. More on this company here...

Anybody have a guess?

Were those taxis allowed to drive customers to either Maryland or Virginia? I sort of remember seeing dual Md and DC plates on autos in photos of that era.

The guy on the left doesn't have his spotlight aimed correctly. Darned useful things, have often wished my present car had one of those.

None of the cabs had expensive and unnecessary headlamps installed. After all, these are work vehicles. But the cowl lamps were electric units.