SAN FRANCISCO - Uber has pulled its self-driving cars from California roads.
    
The ride-sharing company said Wednesday that California transportation regulators revoked registrations for the vehicles.
    
Hours after Uber launched the service in San Francisco, the Department of Motor Vehicles demanded it stop until the company got a special testing permit to run on public roads.
    
Uber argued that the cars weren't technologically advanced enough to require a permit under state regulations.
    
Back-and-forth talks over the past week couldn't bridge the gap.
    
The DMV confirmed that it had moved to revoke the registrations of 16 cars, saying officials had been determined that the registrations were improperly issued because the vehicles were not properly marked as test vehicles.