Enlarge / Uber’s current self-driving cars are based on the Volvo XC90. (credit: Uber)

Four months after a fatal crash forced Uber to halt testing of its self-driving cars nationwide, the company announced Tuesday that it is resuming testing on Pittsburgh streets. But the announcement comes with an important caveat: initially, the cars will only be driven in “manual mode” with human drivers—not Uber’s software—controlling them.

“We’re starting with cars in manual mode, with a Mission Specialist sitting behind the wheel and manually controlling the vehicle at all times,” writes Eric Meyhofer, the leader of Uber’s self-driving car program. “While we are eager to resume testing of our self-driving system, we see manual driving as an important first step.”

Driving around in manual mode won’t allow Uber to directly test its self-driving car software. But it will allow the company to gather data that will improve Uber’s maps and simulation software. It’s also a way for Uber to test the political waters in Pittsburgh before diving in headfirst. Uber’s plan to resume testing in Pittsburgh initially met with criticism from Mayor Bill Peduto.