Associated Incidents
Back in March, an Uber self-driving car killed 49-year-old Elain Herzberg in Tempe, Arizona, after failing to do an emergency stop. After a US federal investigation, it is thought that the car did not stop because the system put in place to carry out emergency stops in dangerous situations was disabled .
National Transportation Safety Board
So, how do self-driving cars actually work? Most self-driving cars have a GPS unit, a range of sensors such as radar, video and laser rangefinders as well as a navigation system. All of these features are there to help the car become aware of its surroundings in order to navigate without the need for human input. Radar is one of the major ways a self-driving car maps its environment. Radar stands for Radio Detection And Ranging which in simple terms is just the transmission of radio waves into a particular direction and the detection of the reflected waves, or echoes, from objects in the surrounding environment. The radio waves are produced by an antenna where electrons are constantly moving up and down via an alternating current. The radio waves are transmitted in pulses and the time taken for the pulse to return provides an indicator into how far that object is. Similarly, laser rangefinders work by measuring the time taken from when the laser beam was transmitted to when it was reflected back.
Data from the sensors, with the help of GPS and an inertial navigation system, allows the car to build a 3D map of its environment and make a decision for its next move via its control system. The algorithm that makes up the control system helps determine a long-range plan for the cars’ next moves where all dangerous or impossible moves are eliminated and harmful objects are taken into account. Once the best path is decided, the moves from the control system are then fed into the actuators of the car which control steering, throttle, and braking.
Regarding the Uber self-driving car, it was found that the emergency braking maneuvers were disabled whilst the car was being controlled by a computer as stated by the National Transportation Safety Board. The sensors on the Volvo XC-90 SUV spotted the woman but because of the disabled emergency braking features the car did not apply the brakes and the human backup driver in the car was not warned, hence, did not intervene in time. It was found that the car was traveling at 43 mph and needed to break 1.3 seconds before impact.
Whilst regulators continue to investigate the cause of the crash, Uber has suspended tests on their self-driving cars in San Francisco, Toronto, Arizona, and Pittsburgh. A spokesperson for Arizona governor Doug Ducey says, ‘We await the more thorough and final investigative report. Uber’s self-driving vehicle suspension remains in place.’