Usage costs for cars are usually tagged at around $0.50-$0.60 per mile [1]. Looking around, seems like the average 8 hour uber driver is putting on about 100-200 miles per shift [2].
So assuming 150 miles per 8 hours, the average uber driver is paying about $11/hr in fuel and depreciation costs.
So the net income after that would probably be more like $9/hr.
1: http://newsroom.aaa.com/tag/driving-cost-per-mile/
2: https://www.quora.com/How-many-miles-does-a-full-time-driver...