Uber Technologies said on Tuesday it would partner with car-sharing service Maven, operated by General Motors, to allow Uber drivers to rent GM vehicles on a weekly basis. The 90-day pilot is a surprise move for Maven and General Motors, which with Lyft – Uber’s main competitor in North America – announced a program in March called Express Drive used mostly by Lyft drivers. Maven operates in 10 U.S. cities. After GM invested $500 million in Lyft in January, the Express Drive program was the first initiative to come out of the partnership.