Single-driver cars also clog up streets. Should we use a medallion system for all licenses?
Cities could use parking enforcement to prevent idling etc. To help control taxi traffic, and traffic in general, they could use tolls, congestion pricing, or, I don't know--build fucking decent public transit. I'm looking at you, Toronto.
The difference is that when a private car reaches its destination, it leaves the road network by entering a parking space. At that point, it no longer contributes to congestion.
A taxi/uber spends about 50% of the time insie the road network without a passenger.
Additionally, some places DO have a "medallion" system for private licenses. You are only allowed to purchase a car with proof that you have a private parking space available. I think this is true in Singapore and some other asian cities.
Just because there aren't regulatory barriers doesn't mean there aren't barriers.
Capital costs (car), insurance costs, marketing, etc.
Except that many (most) people already own a car and thus those are sunk costs. The only barrier to enter the Uber market is a very quick background check.
I didn't ask whether a private medallion systems existed (I already knew about Singapore). My point was that if you support a medallion system for taxis and ride-shares to reduce traffic, why don’t you support one for private cars? They idle less?
Private cars, which usually have no additional passengers, need two parking spots (home and destination), which helps lead to urban sprawl (parking for work, shopping, restaurants, etc.). And in most cities, there are just a ton more private cars on the road than taxis or ride-shares--so they're usually a bigger problem, even if they are not a bigger problem per car.
Edit:
Taxis and ride sharing services (though mostly ride sharing) are bad for city congestion, and they should be discouraged. I offered some suggestions: tolls and congestion pricing. These can be applied to private cars, which also lead to congestion. I could also add a taxi tax or a rush-hour tax specifically for taxis and ride sharing services.
Uber drivers are employees/contractors. They are not entering a market--they are getting a shitty job with no protections. They would face barrier if they were starting their
own taxi or ride-share companies.