Taxis challenge US apps that find ridesharers for car drivers

Two recently-launched San Francisco ride-sharing offers are facing legal probes on the grounds of unfair competition with the city’s taxis. Zimride’s Lyft service and its SideCar competitor use smartphone apps to link up drivers that sign up to the service with pre-booked passengers who then make a contribution to the ride.

With Lyft, the passenger says where they want to go, within a maximum 96km radius. When the ride ends, the app calculates a ‘suggested donation’,...