The restart Thursday comes just over nine months after one of its autonomous cars struck and killed a pedestrian in Arizona. Testing has been suspended since the accident in March.
The ride-hailing company received permission to resume testing from the Pennsylvania Transportation Department on Monday. It plans to start with a few cars in an area near its offices.
Uber has pledged to have two human backup drivers and take other safety precautions in each Volvo SUV. It also will stay in an area where speed limits on most roads are 25 mph.
Uber also plans to resume human-controlled tests in Toronto and San Francisco. It has no immediate plan to resume tests in Arizona.
The company says its SUVs will operate only during daylight hours on weekdays and not in inclement weather.
In addition to the Uber technology that has been installed in the SUVs, it also has activated Volvo's own automatic emergency braking system as a backup to its self-driving controls. In testing that occurred before the pedestrian death in Arizona, Uber had switched Volvo's technology off.