Taxi drivers are hamstrung in their ability to compete with Uber. They don't control the major lever of competition, the ability to lower their fares. They aren't allowed to surge price either, which can boost the supply of cars when and where passengers need them. In many markets, they can't let riders pay by smartphone, or order a car that way.

But taxi drivers do control many aspects of the quality of a ride. And in one fascinating consequence of the rise of Uber, it looks -- in passenger complaint data -- as if taxi drivers under new competition may be trying harder to give you a pleasant ride.

The Technology Policy Institute's Scott Wallsten, in research presented this week at the annual meeting of the American Economic Association, finds evidence in New York that the number of complaints per taxi trip there has declined as Uber has expanded in the city. In Chicago, complaints about air conditioning, "broken" credit card machines and rude drivers have fallen as well with the recent rise of alternatives to taxicabs.