A collaboration between Groupe PSA (Peugeot Citroen) and Vinci Autoroutes has allowed an autonomous vehicle (AV) to pass through a public tollgate in full self-driving mode for the first time.
Last week, a Citroën C4 Picasso from Groupe PSA’s AV fleet crossed through Europe’s largest toll station at Saint-Arnoult-en-Yvelines near Paris in France, without the driver’s assistance, due to a system allowing communication between the vehicle and the motorway infrastructure. The test in real traffic conditions demonstrates a significant step forward in autonomous car development toward the SAE’s Level 4; defined as ‘mind off – without driver supervision’. The demonstration is the outcome of a development program started in 2016, between the auto maker and Europe’s largest operator of motorway infrastructure.
Driving through a toll station is a complex issue for an AV, as it requires management of the cross flow of vehicles moving randomly through the lanes approaching toll booths. It also requires guidance of the AV through an area where there are no road markings, and along a trajectory that automatically enters the specially equipped lane, which is only 9.8ft (3m) wide. The AV must also anticipate any unforeseen events that may occur as it crosses through the toll gate.
The essential communication protocol between Vinci’s infrastructure and PSA’s AV included:
A guidance system that was deployed 1,640ft (500m) ahead of the toll booths, allowing the AV to follow a pre-recorded trajectory, guiding it to the selected and equipped gate, and onto the motorway, where the car can steer itself due to the white lines;
A ‘pass through’ permission sent to the vehicle, indicating whether the gate is open or not, which is transmitted using the ITS G5 protocol from a road side unit (RSU) positioned 984ft (300m) before the toll station;
Modification of the toll station’s information system to enable real-time analysis of the availability of the lane, ensuring the AV can safely pass through the gate;
Providing the C4 Picasso AV with an electronic toll card, enabling it to pass through the lanes in autonomous mode.
“Crossing through a tollgate in autonomous mode is an important step toward Level 4 driving on motorways,” noted Carla Gohin, PSA’s director of innovation. “This experiment shows the potential provided by real-time communications between the vehicle and the road infrastructure. This is the first step in assessing its contribution for different situations that the autonomous car may encounter on the motorway.”