[lambda]

Taxis can be flagged down on the street. All you have to go on is that it looks like a taxi, and has a medallion. If they aren't part of a regulated system with mandatory fares, medallion numbers, safety regulations, you have no idea what you'd be getting into when you flag one down without some kind of regulation.

These, instead, generally count as livery services. If you are calling a specific business to be picked up, you know who you're dealing with ahead of times, and can check their rates, choose based on their reputation, etc.

At least in Boston, Uber drivers are regulated, but as livery not as taxis, as you "call" them rather than hailing them directly on the street.

[CurtHagenlocher]

Thanks, this is what I was looking for. There's a livery service in Seattle called "Seattle Town Car" and now I'm wondering what kind of regulation they face. From what I can tell, Seattle isn't quite a city like Chicago or New York where being able to flag down a cab on the street is both common and important, and I wonder to what extent that plays into the dynamic.

I wasn't generally interested in attacking or defending regulation as such, but the most compelling thing I've heard in favor of regulation is that livery services don't have the same legal obligation as taxi companies to offer vehicles which can serve handicapped people.