- Continental is developing new concepts designed to warn drivers about an imminent risk of hydroplaning
- Hydroplaning assistance concepts utilize surround view camera images and signals from tire-mounted sensors (eTIS) for advanced tire information
- The holistic concept can give the driver time to prevent the front wheel of the vehicle from floating, while warning other vehicles to be prepared for a critical situation
AUBURN HILLS, Mich., April 30, 2018 — Awareness of road conditions is a crucial safety factor as accidents in severe weather arise mainly due to significant loss of friction between the vehicle’s tires and the road. With its Road Condition Observer, technology company Continental has introduced a solution that allows road conditions to be classified with regard to tire and road friction.
Hydroplaning is extremely dangerous for manually-driven and automated vehicles. Continental is developing new sensor-based concepts to warn the driver in the event of imminent loss of friction. When there is a deep layer of water on the road, the water pressure between the tire footprint and the road surface can make the front wheels float. Braking and steering are no longer possible and the driver loses control of the vehicle.
“Wet road conditions are difficult for a driver to evaluate,” said Ibro Muharemovic, head of engineering systems, ADAS, Continental North America. “Once you feel your vehicle floating, it is too late. Our hydroplaning assistance concepts detect the early hydroplaning phase to make the driver aware of what is going on under the tires. This can help drivers or automated vehicles adapt their speed appropriately to wet road conditions.”
The system under development is all encompassing – tires, tire-sensors, cameras, algorithms, brake actuation, and the human-machine interface.
Predictive Hydroplaning Risk Recognition
Continental’s developers are focused on predicting and managing the risk of hydroplaning. The objective is to detect a possible front-wheel floating situation as early as possible to trigger an early warning to the driver. Utilizing signals from surround view cameras and tire-mounted electronic-Tire Information System (eTIS) sensors, an early warning concerning the approaching hydroplaning situation is provided to the driver. Continental is also working on the control and stabilization of vehicles in hydroplaning situations, such as torque vectoring by individual wheel braking.
Hydroplaning conditions can also occur unexpectedly with no opportunity for advance warning. In such cases, the potential risk to other vehicles on the road can be mitigated by early communication via V2X technology and eHorizon, facilitating a network of solidarity where one vehicle acts as a safety sensor for all other vehicles and not just those in its direct vicinity. eHorizon can provide this information to vehicles that could potentially be affected, allowing the driver to adjust their driving functions to the conditions.
Detecting an imminent loss of control through sensor re-use
To detect hydroplaning situations, video images from surround view cameras mounted in the side mirrors, the grill, and rear are analyzed.
“When there is a lot of water on the road, the camera images show a specific splash and spray pattern that can be detected as hydroplaning in its early phase”, explained Muharemovic.
Excessive water displacement in all directions underneath the tire is a characteristic attribute. During the first testing phase of the new solution, the wetness recognition algorithms delivered a very high hit ratio in predicting potential aquaplaning conditions.
In addition to image information, Continental uses information from tires to detect the risk of hydroplaning. In this concept, signals from Continental’s eTIS sensors, mounted on the tire’s inner liner, are computed.
“We use the accelerometer signal from the electronic-Tire Information System to look for a specific signal pattern,” said Michael Crane, vice president, Body and Security Systems, Continental North America.
A tire model processes the incoming radial acceleration from the part of the tire that is in contact with the road. For wet roads – when enough water is transported out of the tread to ensure an appropriate grip – the signal shows a distinct pattern. As soon as a wedge of water begins to form in front of the tire footprint region and there is excessive water on the road, the acceleration signal begins to oscillate in a characteristic way, indicating an early risk of hydroplaning. Since the eTIS sensor can also detect the remaining depth of the tire tread, a safe speed for a given wet road condition can be calculated and communicated to the driver.
Testing has shown that future hydroplaning assistance will also have the potential to intervene in an actual hydroplaning situation by applying the rear brakes in a controlled way to establish a degree of “torque vectoring” in order to maintain vehicle maneuverability within physical limits.
Contribution to Vision Zero
Not only is hydroplaning a challenge to the driver, but it is also difficult to determine how many city road and highway accidents are caused by floating front wheels in wet road conditions.
“This is one of the last blank spots on the strategic map towards greater road safety,” said Muharemovic. “But drivers must continue to adjust their speed to wet roads and keeping an eye on the tire’s tread depth.”
Since hydroplaning depends on tread depth, the height of the water on the road and speed, Continental recommends renewing summer tires with three millimeters of residual tread depth. Below this limit, the risk of aquaplaning increases significantly.
Continental develops pioneering technologies and services for sustainable and connected mobility of people and their goods. Founded in 1871, the technology company offers safe, efficient, intelligent and affordable solutions for vehicles, machines, traffic and transport. In 2017, Continental generated sales of €44 billion and currently employs more than 240,000 people in 61 countries.