(Image courtesy of Volvo).

How Automakers Handle Handoffs to Self-Driving Cars

Aug. 1, 2017
Other automakers, from Google to Ford, have passed on engineering a system that can safely switch control from human drivers to cars to humans again.

There is little doubt that fully autonomous cars will reduce the number of deadly collisions caused by human mistakes on the road. But many experts fear that roads could grow more dangerous with semi-autonomous vehicles that need humans to take over in emergencies.

The problem stems from the fact that drivers must be prepared to take over control from a vehicle when it starts raining heavily, sensors fail, or highway lines fade. The semi-autonomous system could lull drivers into a false sense of security, leading to accidents if they fumble with retaking control while playing a smartphone game or have trouble adjusting to the feel of the steering wheel.

It is an extremely tough engineering nut to crack, and many engineers have stopped trying to solve it. That is why Google gutted the steering wheels and pedals in its experimental cars to focus on fully self-driving cars. Ford and Volvo have separately announced plans to aim for higher levels of autonomous driving that allow drivers to read or watch television.

But many companies contend that what Bryant Walker Smith, an assistant professor of law and engineering at the University of South Carolina, terms the “mushy middle” of autonomous driving can improve highway safety and provide insight into new technologies. These manufacturers are tackling "handoffs" in many different ways.

Audi Last month, the company officially announced the A8, which will be the first production vehicle with Level 3 autonomous driving. This level allows drivers to watch television or read in highway traffic jams. The car sends audio and visual alerts in emergencies, giving drivers eight to ten seconds to retake control. If the alerts are ignored, the car will even tighten the seat beat and pump the brakes, Wired reports.

Continental Last month, automotive supplier Continental said that its semi-autonomous driving system would be similarly introspective, monitoring drivers’ attention levels with cameras after they push a button to cede control. The system will make visual and audio overtures in emergencies, making noises, buzzing the seat, and flashing warnings on the dashboard.

If drivers ignore the alerts, vehicle using the Cruising Chauffeur system will find a highway shoulder or other safe place to stop. Continental said that the technology, which qualifies as Level 3 autonomous driving, would be ready for production in vehicles by 2020.

Autoliv The parts supplier has been testing a steering wheel ringed with infrared sensors that detects when a driver’s hands are clutching the wheel. Autoliv programmed a vehicle to enter self-driving mode when drivers take their hands off the zForce steering wheel, allowing them to regain control simply by grabbing onto it again. This results in safer handoffs, Autoliv says.

Tesla After a driver died in a collision while using Tesla’s Autopilot system last year, the electric car maker updated its software to make crystal clear to drivers that their hands must always stay on the wheel. Now if drivers ignore reminders to hold the wheel for more than 15 seconds, Tesla’s vehicles will slowly grind to a halt.

If the driver ignores too many alerts, the vehicle will disable the so-called Level 2 system – which means that the driver must be prepared to take control at a moment’s notice – until the entire car is restarted. In March, Tesla also updated the software to that drivers must hit the turn signal to make automatic lane changes.

General Motors The SuperCruise system to be installed in the Cadillac CT6 later this year will monitor a driver’s gaze with an infrared camera embedded in the steering column. Holding the wheel is optional but the Level 2 system will alert drivers whose eyes have strayed from the road too long. If drivers ignore these alerts, a light bar starts glowing on the wheel and the vehicle resorts to visual and audio warnings.

Mercedes Benz The Level 2 autonomous driving mode that Daimler will introduce this year requires more attentiveness. With Drive Pilot, drivers can take their hands off the wheel. But the vehicle will check every ten seconds that the driver has pressed two capacitive touch buttons on the wheel, otherwise it will send reminders on the dashboard and then make a repetitive bonging noise to grab the driver’s attention.


To join the conversation, and become an exclusive member of Electronic Design, create an account today!