During the three-city pilot program, Uber will offer drivers $300 to install the vehicle-topper and an additional $100 each week they drive more than 20 hours. Once the program is up and running, drivers will be paid based on how many hours they drive. The displays will show eight-second still or video ads, based on location and time of day.

The displays should start showing up by April 1st, and they'll be overseen by a new Uber business unit called Uber OOH Powered by Adomni. This is Uber's first step into the world of advertising, which is a bit surprising given that traditional taxis have long-displayed ads. Uber previously said it expects to be profitable by the end of 2020, and this advertising strategy could play a part in that.

Uber could face competition, though. Just yesterday, Lyft announced that it acquired Halo Cars, a startup that lets drivers for app-based car services run taxi-style ads on top of their vehicles. And, of course, not all drivers will want to be rolling advertisements.