Human Cloud, ride-sharing firm Uber is changing its rate structure to encourage drivers not to cancel as many rides, USA Today reported. Instead of being charged only by distance, with cars sometimes sitting in traffic, the new rates factor in time and distance. “We are increasing your per-minute rate on each trip so that your earnings are more consistent, regardless of traffic or unexpected delays,” Uber said in an e-mail sent Thursday to drivers in 14 cities. “Your time is now being valued at a higher rate.”