Starting later this month, Uber will allow customers in downtown Pittsburgh to summon self-driving cars from their phones, bringing the first self-driving car-sharing service to market, Bloomberg reports. Uber’s Pittsburgh fleet will be supervised by humans in the driver’s seat for the time being and consist of specially modified Volvo XC90 sport-utility vehicles. The two companies signed a pact earlier this year to spend $300 million to develop a fully autonomous car that will be ready for the road by 2021. Uber also plans to partner with other automakers as it races to recruit more engineers, according to Bloomberg. In July, the company reached an agreement to buy Otto, a 91-employee driverless truck startup that was founded earlier this year and includes engineers from a number of high-profile tech companies attempting to bring driverless cars to market.