Can Uber regulate the condition of their cars?

A Couple of weeks ago I was on a business trip to San Francisco and rather than rent a car, the group I was with decided to use Uber to get around. The service itself was pretty slick, but the condition of the cars was something that definitely needs some sort of regulation. Don't get me wrong - I love the idea of Uber, but the implementation of it from a safety point of view leaves a lot to be desired.
Over the 5 days we were there, we Uber'd 6 times. The initial ride picked us up from the airport in the middle of a reasonably strong California downpour. Low visibility, roads covered in standing water, lots of spray. The tyres on the car that picked us up were not so much bald as they were non-existent. The driver had gone through the tread and was driving on the canvas cords and steel bands. That car wouldn't have been safe in the dry. In the wet it was like driving on teflon. We aquaplaned on the slightest puddle but the driver didn't seem phased.
The second ride was fine in terms of the car (a Prius) but the driver was the scary part that time around. His driving style was either 100% accelerator or 100% brake and red lights meant nothing to him.
The third ride was about the best of the bunch - a reasonably new Chevy Tahoe in good condition with a careful driver.
The remaining rides were a combination of poorly maintained cars (massive oil leaks, no brakes, no tread on the tyres, broken headlights and such) and drivers who were more willing to get into a knock-down-drag-out fight than they were to drive us to our destination (because we refused to get into a car that had the exhaust dragging on the road).
I know there are horror stories on both sides of the divide for Uber - both from drivers who had terrible passengers, and from passengers like us who had a wildly variable set of rides and drivers. One of those is easier to fix than the other - the actual vehicles. Regulations exist in the taxi industry for a reason - generally to try to ensure some level of safety. (Although that being said, I've also travelled in regular taxis in America where even regulated businesses seem able to put total deathtraps on the road).
Uber is a great idea, but until they come up with some way of guaranteeing the basic condition of the driver's vehicles, I think I'm going to pass on it for the time being.