- Driver assistance systems for safe lateral and longitudinal vehicle control in complex urban scenarios are intended to reduce the number of traffic accidents.
- Vehicle connectivity and communication with the infrastructure help make urban traffic safer, more efficient and more comfortable.
International automotive supplier Continental is presenting new systems for driver assistance and vehicle connectivity in city traffic at the midterm event of the research initiative UR:BAN (Urban Space: User oriented assistance systems and network management), which is taking place at the German Aerospace Center (DLR) in Braunschweig. The systems are intended to support drivers and increase safety in dense city traffic, while allowing a forward looking and environmentally friendly style of driving. The goal is to reduce the number of urban traffic accidents and, if this is not feasible, to mitigate their severity while increasing traffic efficiency and driving comfort.
Assistance systems for safe lateral and longitudinal vehicle control in urban areas
Recognizing hazards and reacting to them appropriately in complex scenarios such as city traffic, presents a particularly demanding task. Together with other automotive suppliers and car manufacturers, Continental is researching and developing effective urban assistance systems prototypes, designed to support drivers in dealing with constrictions, changing lanes, oncoming traffic in a narrow passage and reacting to emergency situations; all as part of the project “Cognitive Assistance”. “It is our intention to avoid serious accidents and to make city driving easier by developing new lateral and longitudinal assistance systems”, said Dr. Stefan Lüke, head of the sub-project “Safe Lateral and Longitudinal Vehicle Control in Cities”. Lüke is also head of Advanced Driver Assistance Systems & Automation within the Advanced Engineering department of Continental’s Chassis & Safety Division. The sub-project comprises four functions: constriction assistance, oncoming traffic assistance, lane change assistance, and environment-adaptive speed recommendation.“The functions promote traffic flow, heighten efficiency and reduce pollution in dense urban traffic. Above and beyond that, they help timid drivers negotiate city traffic safely and confidently”. The key to these assistance functions lies in the reliable recognition of other active and passive road users as well as of other objects in complex urban environments, such as traffic signs, traffic lights or parking cars. Surrounding sensors play a critical role. Four short range radars located on the corners of the car, as well as a forward looking long range radar and a stereo camera capture and recognize the surroundings in front of, next to and behind the vehicle, thus establishing an all-around view.
The constriction assistant supports drivers through narrow lanes, when passing a line of vehicles in neighboring lanes, stationary obstacles, or parked cars. It does so by an intervention on the steering wheel, similar to those exerted by the lane keeping assistant. If the constriction is too narrow for the car to pass through, a warning signal sounds and icons appear on the instrument cluster. In case there is no reaction on the part of the driver, the constriction assistant can even trigger automatic safety braking.
The oncoming traffic assistant evaluates oncoming vehicles in city traffic to determine whether they could pose a hazard to a vehicle driving through a narrow passage. If the space is indeed too narrow for both vehicles to pass simultaneously, the assistant advises the driver to stop when a constriction is too narrow accordingly.
The lane change assistant with all-around vision supports drivers on multi-lane city streets. The position of the driver’s vehicle within its lane is determined (other lanes are also monitored, including those to the rear of the vehicle) with the help of surrounding sensors, to determine whether a safe lane change is possible. If so, a guided lane change can be carried out on request. The driver can overrule the longitudinal and lateral assistance at any time by turning the steering wheel or by applying the brakes.
Environment-adaptive speed recommendation is intended to make driving in city traffic safer and more efficient. The Accelerator Force Feedback Pedal (AFFP) by Continental along with changes in engine torque, provide the driver with haptic feedback, which recommends a reduction in speed. The signals allow drivers to adjust their driving behavior in anticipation, and to recognize critical situations earlier.
Continental is participating in other sub-projects in addition to “Safe Lateral and Longitudinal Vehicle Control in Cities”. Reliable recognition of pedestrians and cyclists, plus the refinement of the environmental model, are at the forefront of research into driver assistance systems. Work is underway on emergency interventions in combination with evasive maneuvers and braking to avoid accidents with pedestrians, in particular. Protecting vulnerable road users is becoming increasingly important, especially since it has been added to the rating scheme for the Euro NCAP crash test used in assessing new cars.
Networking and communication promote efficient and safe urban traffic
Continental demonstrates in UR:BAN’s “Networked Traffic System“ project that urban traffic can flow better, more efficiently and safer if cars communicate with traffic lights and obtain information from the Internet. simTD, one of the world’s largest research projects on Car-to-X technology (C2X), has already proven the suitability of C2X for everyday use in improving traffic safety, and keeping traffic moving.
“In principle, we connect cars with an intelligent infrastructure. In doing so, we are creating an extended electronic horizon that permits drivers to anticipate situations beyond their field of vision“, explained Dr. Hongjun Pu, project manager for Advanced Technologies in Continental’s Infotainment & Connectivity business unit. “For example, if we have information on traffic-light cycles and if we also know where a car is, we can calculate in advance the speed range the car needs to maintain in order to avoid red lights”.
Avoiding red lights with intelligent infrastructureThe vehicle receives location-based data about traffic-light cycles via the mobile network. The vehicle then calculates a recommended speed along the Most Probable Path for the next few kilometers using the above data, along with positional data obtained, for example, from the M2XPro-Module (Motion Information to X Provider) by Continental. On the basis of such data, Continental can thus predict the most efficient, fluid way to drive in urban traffic. Carmakers can use this principle to either inform drivers directly or, for example, to fine-tune the longitudinal vehicle control with adaptive cruise control.
If a vehicle approaches a crossing, it can directly communicate with the traffic light via the specially designated WLAN ITS-G5 standard designed for vehicle-to-vehicle and infrastructure communication. With the aid of this direct communication, the vehicle receives reliable and precise data about the crossing, the traffic-light cycle, the crossing’s geography and geometry, plus the effective speed limit via the MAP (intersection topology) feature and SPaT (Signal Phase and Timing). The system can even convey current situations to the vehicle such as an emergency change in the traffic light signal or a lane closed due to construction. Drivers learn which lane they must switch to and what speed they need to maintain to make it through a green light, or when they will need to stop at a red light. “This makes traffic flow better, but it can also be used to adopt a cruise strategy in sufficient time to take advantage of energy recuperation before an unavoidable stop or to prepare the start-stop feature to start the engine shortly before the light changes to green”, explained Pu. “The combination of direct and indirect communication between vehicle and infrastructure allows us to expand a driver’s horizon with data from the Internet while factoring what is happening at an intersection into the driving strategy”.