A road condition detection device, to be coupled to the wheel of a vehicle, is provided with: an electrostatic charge variation sensor, to provide a charge variation signal indicative of an electrostatic charge variation associated with the rotation of the wheel; and a processing unit, coupled to the electrostatic charge variation sensor to receive the charge variation signal and furthermore for receiving a rotation speed signal indicative of the rotation speed of the wheel. In particular, the processing unit jointly processes the rotation speed signal and the charge variation signal to detect a road condition of a wet road condition and a dry road condition.

Systems and methods are disclosed for estimating slipperiness of a road surface. This estimate may be obtained using an image sensor mounted on a vehicle. The estimated road slipperiness may be utilized when calculating a risk index for the road, or for an area including the road. If a predetermined threshold for slipperiness is exceeded, corrective actions may be taken. For instance, warnings may be generated to human drivers that are in control of driving vehicle, and autonomous vehicles may automatically adjust vehicle speed based upon road slipperiness detected.

Methods, apparatuses, systems and computer program products for estimating individualized road condition information for a specific vehicle are disclosed. Generic road condition information is received, which is indicative of at least one condition of a road segment. Further, individualization information is received, which is representative of an estimating method to be performed on the generic road condition information to obtain individualized road condition information for the specific vehicle. Individualized road condition information are estimated for the vehicle, wherein the estimating method is applied to the received generic road condition information to obtain individualized road condition information.

A method for controlling a vehicle brake system for a heavy duty vehicle including a primary brake system and an auxiliary brake system. The method includes configuring a wheel slip magnitude limit, obtaining a requested auxiliary brake torque, engaging the primary brake system at a torque determined in dependence of the requested auxiliary brake torque, while monitoring a wheel slip value, determining an allowable auxiliary brake torque in dependence of the requested auxiliary brake torque and the wheel slip value, and engaging the auxiliary brake system at the allowable auxiliary brake torque.

A braking system for a heavy duty vehicle includes a first brake controller arranged to control braking on a first wheel and a second brake controller arranged to control braking on a second wheel, based on a respective configured wheel slip limit and on a respective brake torque request, wherein the first and the second brake controllers are interconnected via a back-up connection arranged to allow one of the first and the second brake controller to assume braking control of the wheel of the other of the first and the second brake controller in case of brake controller failure, the braking system comprising a control unit arranged to, in response to brake controller failure, reduce the configured wheel slip limit associated with the failed brake controller to a reduced wheel slip limit.

Method for estimating a brake factor parameter, the brake factor parameter being defined as a ratio of a braking torque over a braking pressure, the braking torque being applied on a wheel of a vehicle by a braking wheel sub-system of a braking system of the vehicle, the braking pressure being applied by the braking wheel sub-system to achieve the braking torque on the wheel of the vehicle, the method comprising collecting input parameters and estimating the brake factor parameter as a function of the at least one input parameter, an output of the step of estimating being an open loop estimation of the brake factor parameter.

Techniques are described for estimating road friction between a road and tires of a vehicle. A method includes receiving, from a temperature sensor on a vehicle, a temperature value that indicates a temperature of an environment in which a vehicle is operated, determining a first range of friction values that quantify a friction between a road and tires of a vehicle based on a function of the temperature value and an extent of precipitation in a region that indicate a hazardous driving condition, obtaining, from the first range of friction values, a value that quantifies the friction between the road and the tires of the vehicle, where the value is obtained based on a driving related behavior of the vehicle, and causing the vehicle to operate on the road based on the value obtained from the first range of friction values.

A road surface state determination device includes a tire-side device and a vehicle-body-side system. The tire-side device is attached to a tire of a vehicle. The vehicle-body-side system is included in a vehicle body. The tire-side device outputs a detection signal corresponding to a magnitude of vibration of the tire. The tire-side device generates road surface data indicative of a road surface state shown in a waveform of the detection signal. The tire-side device transmits the road surface data. The vehicle-body-side system receives the road surface data transmitted from the tire-side device. The vehicle-body-side system determines the road surface state of a road surface on which the vehicle is traveling based on the road surface data and learning data.

An apparatus for estimating a friction coefficient of a road surface is provided. The apparatus includes a current sensor configured to measure a control current value of a rear wheel steering (RWS) motor, a stroke sensor configured to measure a stroke value indicating a movement amount of a rear wheel steering link, and a controller configured to estimate the friction coefficient of the road surface based on the control current value measured by the current sensor and the stroke value measured by the stroke sensor.

A system for estimating the friction between a road surface and a tire of a vehicle includes at least one first sensor and at least one vehicle processing device containing a friction estimation algorithm which is arranged to estimate the friction between the road surface and the tire of the vehicle based on friction related measurements is provided. The vehicle processing device is arranged to: receive an estimate of the expected friction between the road surface and the tire of the vehicle from a central processing device, from a storage device in the vehicle, or from at least one second sensor in the vehicle; adapt the friction estimation algorithm based on said received estimate of the expected friction; receive at least one friction related measurement from the at least one first sensor in the vehicle; and use the adapted friction estimation algorithm to perform an estimation of the friction between the road surface and the tire of the vehicle based on the at least one friction related measurement.