In Berlin, the DRIVE C2X consortium is presenting the results of the field operational tests (FOTs) on vehicle-to-vehicle (V2X or C2X) and vehicle-to-infrastructure (V2I or C2I) technologies (collectively V2X or C2X) in Europe. (Earlier post.) With 34 partners, 13 support partners and a €18.5-million (US$25 million) budget, the three and one-half year DRIVE 2CX project, coordinated by Daimler, was intended to lay the foundation for the roll-out of vehicle-to-X cooperative systems in Europe.
Previous projects such as PReVENT, CVIS, SAFESPOT, COOPERS, and PRE-DRIVE C2X showed the feasibility of safety and traffic efficiency applications based on C2X communication. DRIVE C2X went beyond the proof-of-concept and addressed large-scale field trials under real-world conditions at multiple national test sites across Europe. During the project, more than 750 drivers tested eight safety-related functions of cooperative functions.
The operational tests took place in seven test sites in Finland, France, Germany, Italy, Netherlands, Spain and Sweden. In total, more than 200 vehicles drove more than 1.5 million km (932,000 miles). A “faultless performance” of the functions during these extensive field trials has shown that the system is mature for deployment, the partners said.
The systems tested were built according to the common European architecture for cooperative driving systems defined by COMeSafety, guaranteeing compliance with the upcoming European ITS standards. For the first time in Europe, DRIVE C2X also implemented and tested a concept for the integration of a data backend, therefore enabling commercial services based on C2X communication data to private and commercial customers.
Such services are expected to become a major revenue source for cooperative driving systems and could be the key for successful implementation of this technology on European roads, the partners suggested.
The eight functions implemented in the test sites for user tests were:
Approaching Emergency Vehicle Warning (AEVW). The system warns drivers to give way to an approaching emergency vehicle, identified by flashing emergency lights and sirens. The driver is informed at an early stage to prepare for the approaching emergency vehicle, e.g. to get out of the way or to stop. As a result the emergency vehicle can reach its target destination faster. Also, the risk of accidents between the driver‘s car and the emergency vehicle is reduced.
￼ Traffic Jam Ahead Warning (TJAW). The driver is alerted when he is approaching a hazardous tail end of a traffic jam, e.g. tail-end behind a hilltop or curve very fast. This system notifies the driver about traffic jams at an early stage. Based on that, drivers can react calmly and safely. The system’s objective is to avoid severe or fatal rear-end collisions which are often caused by traffic jams on highways. This increases the safety of both vehicles that approach a traffic jam and those at its tail-end.
￼ In-Vehicle Signage (IVS). Via Infrastructure-to-Car Communication the driver receives information about currently active valid traffic signs. Road Side Units, mounted on traffic signs and also on key points along the roadway, send messages to approaching vehicles. They raise drivers’ awareness of potentially dangerous conditions in case a traffic sign is not noticed. Traffic signs are displayed on the in-vehicle display.
In-Vehicle Signage was tested in three variations. In the Speed Limit variation, when the driver approaches the speed limit sign, a pictogram of the speed limit sign is shown in the right side of the display. If the driver is exceeding the speed limit significantly, a background imitating a speedometer is shown in the middle of the display in addition to the speed limit sign. The driver also receives an audible alert.
In the Child Sign variation, when the driver approaches the child sign, a pictogram of this traffic sign is shown in the right side of the display. Information about the child sign can be displayed e.g. near schools or kindergartens.
Finally, in the Yield Sign variation, when the driver approaches the yield sign, a pictogram of this traffic sign is shown in the right side of the display. Information on the yield sign is shown only when the driver is obliged to give way in the intersection.
Road Works Warning (RWW). The Road Works Warning-System warns drivers at an early stage when approaching a road works area, e.g. road building, maintenance, mowing. This alert prepares the driver for the impending event so that the driver can already start to slow down the vehicle, if appropriate.
Therefore, safety relevant information will be communicated to the driver, e.g. speed-limit or lane closures. The system‘s goal is to reduce the likelihood of crashes during road works and to increase the safety of travellers and road workers.
Obstacle Warning (OW). The driver receives a warning about an obstacle lying on the road ahead. In order to reduce the probability or severity of an accident, the driver is prepared for an upcoming obstacle on the road, e.g. lost cargo. As a result, he or she can slow down the vehicle.
Car Breakdown Warning (CBW). A vehicle brought to a standstill in the middle of the road notifies oncoming drivers of the situation, in order to alert a potential risk of collision. This information is particularly useful when the vehicle concerned is not immediately visible, e.g. in a blind curve or on a crest, in fog.
This information is provided to the drivers a few moments before they reach the halted vehicle. The cause for the standstill might be an accident, a breakdown, or a human issue.
Weather Warning (WW). The Weather Warning system gives the driver information and warnings about dangerous weather conditions like cross winds, fog, heavy rains and snow or black ice on the road. The warning is automatically triggered by vehicles ahead reaching the area. The driver is encouraged to adapt his or her driving behavior to the weather conditions to avoid weather related accidents.
Green Light Optimal Speed Advisory (GLOSA). The driver receives a speed recommendation allowing him or her to pass a green traffic light ahead while sticking to given speed limits. If it is not possible to pass the signal within the given speed limit, no recommendation is shown to the driver. If the signal is red, information about the remaining time until the signal turns green is displayed.
According to the speed recommendation the driver is able to adjust the vehicle's speed within the given limit. The main purpose of the system is to optimize traffic efficiency: As unnecessary acceleration and deceleration is reduced, the traffic flow is optimized, and emission and fuel consumption is reduced.
The tests demonstrated a positive impact of DRIVE C2X on safety and efficiency. Drivers reacted to information and warning signals. As an example, the In-Vehicle Signage (IVS) on speed limit and Weather Warning (WW) showed most potential to decrease fatalities.
Assuming a 100% penetration rate, IVS speed limit that provides continuous information would reduce on average 23% in fatalities and 13% in injuries. WW would lead to 6% less fatalities and 5% less injuries. From an efficiency perspective, functions such as the In-Vehicle Signage (IVS) on speed limit and Green Light Optimized Speed Advisory (GLOSA) indicated significant effects for both the environment and traffic efficiency. Drivers reacted to the information by reducing their speed in most cases.
User acceptance is high with nine out of ten test users welcoming the cooperative systems. Users indicated that they are willing to use it if it were available in their vehicles. The test results also demonstrate a positive impact on travel comfort. Specifically, journey quality is improved in terms of decreased user uncertainty and stress, and feeling of safety and comfort.
Moreover, DRIVE C2X also shows evidence for economic viability thanks to more than 50 interviews with representatives across all major stakeholder groups. The interviews revealed that the economic potential can significantly be increased if cooperative systems are launched both as standard equipment and open to third party applications.
The benefits of the DRIVE C2X system result from an increase in safety—less or less severe accidents—and decrease of traffic congestion. Comparing the benefits of C2C and C2I-technology, the project concluded that the benefits resulting from infrastructure-based systems are slightly higher than those from C2C-technology.