Regulations in California are forcing Google officials to add steering wheels and brakes to their driverless car prototypes, The Wall Street Journal reports.
Google unveiled a model of its driverless car that had no steering wheel, brakes or gas pedals in May.
California rules require autonomous cars that been testing in the state to have an option for drivers to take control in an emergency, according to the report.
“With these additions, our safety drivers can test the self-driving features, while having the ability to take control of the vehicle if necessary,” Google spokeswoman Courtney Hohne said.
Google said previously that it intends to build about 100 prototype driverless cars for a test program.
Driverless cars have excited lawmakers and also presented a challenge to existing liability rules for insuring cars and determining responsibility for potential accidents.
Lawmakers conducted test drives of a model driverless car that was operated by Carnegie Mellon University earlier this year, though some congressional critics have expressed trepidation at the thought of computer-powered cars being operated on U.S. roads.