HELLA Road Condition Sensor (RCS/SHAKE)

Reliable warning for wet roads

Road wetness is very often underestimated. This is because the so-called hydroplaning effect can occur abruptly on wet road surfaces if driving speed is not adjusted. In this case, the tires can no longer sufficiently displace the water at high speed – they lose grip, the direct connection to the road surface. The tires literally “float” upward. As a result, the driver loses control of the vehicle, similar to black ice, and can no longer steer it with the steering wheel. The result is often serious accidents, especially at high speeds on highways.


To reliably prevent hydroplaning, drivers must be made aware of road conditions in time in order to be able to adjust their driving behavior accordingly.


This is where the HELLA Road Condition Sensor (RCS) comes into play: It collects data regarding road wetness and delivers this information to various driver assistance systems for further processing. These systems can then react accordingly to the respective wetness situation and/or issue warning messages for the driver.


The key points in short

  • Early and reliable detection of road wetness during the day and at night
  • Warning option to prevent hydroplaning in wet conditions
  • Fast data acquisition and calculation, communication via standardized LIN protocol
  • Input variable for driver assistance systems, e.g. braking and control systems
  • Long-standing, robust measuring principle of airborne and structure-borne sound analysis in the wheel well

Perfectly positioned for greater safety

The HELLA Road Condition Sensor (RDS) is positioned in the vehicle's wheel well, or on each front wheel well cover specific to the application, and constantly measures the amount of fluid present on the road. In this way, in conjunction with driver assistance systems such as ABS and ESP, the risk of hydroplaning can be effectively reduced by detecting excessive road wetness in time. The driver assistance systems can intervene accordingly or issue warnings, alerting the driver to adjust driving behavior.


Thanks to the HELLA Road Condition Sensor, the assistance systems can, for example, predict the braking distance depending on the wetness of the road, adjust the control systems of the longitudinal and lateral dynamics, or influence the distance to the vehicle in front.


Lightning fast signal transmission

When the road is wet, the tires stir up water, which causes vibrations and noise in the wheel wells. These parameters are recorded or measured by the Road Condition Sensor and converted into the respective water film height in real time using special algorithms. The integrated sensor electronics and the intelligent software process this signal immediately afterwards and transmit the information via a bidirectional LIN interface (LIN = Local Interconnect Network) to the respective vehicle control unit. The control unit can then initiate further steps: For example, the activation thresholds for the anti-lock braking system (ABS) or traction control can be lowered. The transmitted sensor data can also be used to adjust the drive train control system to achieve greater chassis stability, such as when cornering.

Advanced driver assistance systems used in partially or fully automated (=autonomous) driving can also benefit from the data collected and calculated by the RCS and, for example, dynamically adjust the distance to the vehicle in front (ACC).


Exceptionally robust

The HELLA Road Condition Sensor not only ensures reliable measurement, calculation, and transmission of road wetness, but is also exceptionally robust in the process. This is the only way to ensure that the sensor functions perfectly at all times, under all operating conditions and even under heavier loads – for the sake of safety. The RCS is therefore absolutely dustproof and waterproof, protected against impacts and stone chips, and resistant to road salt. Even twisting in the wheel arch shell while driving is no problem for the sensor. It can also be operated at extreme temperatures between -40 °C and 90 °C.


The HELLA Road Condition Sensor can detect road wetness up to a speed of 180 kilometers per hour and thus makes an important contribution to greater safety.


No more fear of wet roads – thanks to the HELLA RCS!


More information can be found here

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