NEIGHBOURING TRAFFIC LANES

5 TECHNICAL AREA

The invention relates to a method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to the introduction to claim 1 . The invention relates to a system to assess the risk of change of traffic lane 10 during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes. The invention relates also to a motor vehicle. The invention relates also to a computer program and a computer program product.

15 BACKGROUND

When driving a vehicle on a roadway with at least two neighbouring traffic lanes, a change of traffic lane involves a risk in the case in which a vehicle behind is approaching in the neighbouring traffic lane to which a change is to take place. From the point of view of traffic safety, thus, there is a need to 20 assess the risk of change of traffic lane in the presence of vehicles that are approaching the leading vehicle from behind.

What is known as a "blind-spot warning system" is, according to one variant, used for this purpose. Such a system warns or takes action in another manner when the driver's own vehicle is in the process of progressing into a 25 neighbouring traffic lane in which a vehicle that is approaching the driver's own vehicle from behind is present or will become present in the near future. This is normally achieved by means of a rearwards-directed radar that detects vehicles in neighbouring traffic lanes, where it is assumed that the leading vehicle and the vehicle that is approaching it from behind are being driven essentially straight ahead along the direction of travel.

PURPOSE OF THE INVENTION One purpose of the present invention is to achieve a method and a system to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes that ensures effectively whether change of traffic lane is possible and in this way improves safety without unnecessary warnings being generated during the change of traffic lane.

SUMMARY OF THE INVENTION

These and other purposes, which are made clear by the description below, are achieved by means of a method, a system, a motor vehicle, a computer program and a computer program product of the type described in the introduction, and that further demonstrate the distinctive features specified in the characterising part of the attached independent patent claims. Preferred embodiments of the method and the system are defined in the attached non- independent claims. According to the invention, these purposes are achieved with a method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes, comprising the steps: to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle; to determine continuously the relative speed between the vehicles, comprising the steps: in the event that the relative speed that has been determined demonstrates that the said vehicle that is behind the leading vehicle is approaching it, to determine continuously when the said vehicle that is behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven. Safety is in this way improved since a warning will be given when this is required, and can be avoided in the case in which the vehicle behind has not been determined to constitute any risk in that it will not be located in the action zone during the change of traffic lane. It is, consequently, ensured in this way in an effective manner whether a change of traffic lane is possible, whereby safety is improved without unnecessary warnings being generated during the change of traffic lane.

According to one embodiment, the method comprises the steps: to determine, based on specifications concerning the extent of a specified traffic lane in which the leading vehicle is being driven, the extent of at least one neighbouring traffic lane based on continuously determined reference positions at the leading vehicle relative to the said neighbouring traffic lane in order to determine the said risk zone extending a specified extent in the said neighbouring traffic lane backwards from the said leading vehicle. By determining relevant risk zones in this way, the risk of erroneous warnings in which risk during the change of traffic lanes is not present and the risk of omitted warnings when risk during the change of traffic lanes is present are minimised.

According to one embodiment, the method comprises the steps: to determine, based on specifications concerning the extent of a specified traffic lane in which the vehicle is being driven, the extent of at least one neighbouring traffic lane based on continuously determined reference positions at the vehicle relative to the said neighbouring traffic lane in order to determine the said action zone extending a specified extent in the said neighbouring traffic lane alongside the said vehicle and, in the event of the presence of objects in the said action zone, to take measures in association with a change of traffic lane. By determining relevant risk zones in this way, the risk of erroneous warnings when there is no risk of change of traffic lanes is minimised. Consequently, in this way, the risk of erroneous warning when a vehicle with a trailer, such as an articulated lorry, is driven around a curve is eliminated in that the action zone deternnined in this way will not be sensitive to the driver's own trailer.

According to one embodiment, the method comprises the step to take into consideration during the said risk assessment the relative speed when determining how rapidly a change of traffic lane of the leading vehicle takes place. The safety is in this way further improved in that a warning is given in the case in which it is determined that the leading vehicle will be present in the action zone during the change of traffic lane when the vehicle that is approaching it from behind will arrive at the action zone, and a warning can be avoided when the vehicle behind has not been determined to constitute any risk in that it will not be located in the action zone during the change of traffic lane through it being determined that the vehicle behind will have sufficient time to pass or will not have sufficient time to reach the action zone before the leading vehicle has carried out the change of traffic lane and is located in the action zone.

According to one embodiment, the method comprises the step to take information about the situation of the leading vehicle in its traffic lane into consideration when determining how rapidly a change of traffic lane of the leading vehicle takes place. By taking in this way into consideration, for example, the situation such as the position of the vehicle, the possibility of determining how rapidly the change of traffic lane will take place is improved, whereby the safety is further improved. In this case a warning is given for the case in which it is determined that the leading vehicle during the change of traffic lane will be present in the action zone when the vehicle that is approaching it from behind has arrived in the action zone, and a warning can be avoided when the vehicle behind has not been determined to constitute any risk in that it will not be located in the action zone during the change of traffic lane through it being determined that the vehicle behind will have sufficient time to pass or will not have sufficient time to reach the action zone before the leading vehicle has carried out the change of traffic lane and is located in the action zone.

The embodiments of the system demonstrate corresponding advantages as corresponding embodiments of the method described above.

DESCRIPTION OF DRAWINGS

The present invention will be better understood with reference to the following detailed description read together with the attached drawings, where the same reference numbers refer to the same parts throughout the several views, and where:

Figure 1 illustrates schematically a motor vehicle according to one embodiment of the invention;

Figure 2 illustrates schematically a block diagram of a system to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to the present invention;

Figure 3 illustrates schematically the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes, where reference positions relative to traffic lanes that are neighbouring to the vehicle have been determined;

Figures 4a and 4b illustrate schematically the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes, where vehicles that are approaching the leading vehicle from behind are detected according to one embodiment of the present invention; Figure 5 illustrates schematically a block diagram of a method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to the present invention; and

Figure 6 illustrates schematically a computer according to one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

In this document, the term "link" refers to a communication link that may be a physical line, such as an opto-electronic communication line, or a non- physical line, such as a wireless connection, for example a radio link or microwave link.

In this document, the term "neighbouring traffic lane" refers to neighbouring traffic lanes for vehicles travelling in the same direction, i.e. traffic lanes in the form of neighbouring lanes in which vehicles travel in the same direction, commonly found on larger roads such as motorways, and to neighbouring traffic lanes for travel in the opposite direction, i.e. neighbouring traffic lanes in which oncoming traffic is present in the neighbouring traffic lane and in which overtaking manoeuvres can take place.

Thus, in this document, the term "roadway with at least two neighbouring traffic lanes" refers to any appropriate roadway with neighbouring traffic lanes according to the definition above. Thus, the term "roadway with at least two neighbouring traffic lanes" can consequently include a larger road such as a motorway with two or more neighbouring traffic lanes in the form of neighbouring lanes for travel in the same direction, a roadway with two neighbouring traffic lanes for travel in opposing directions, i.e. neighbouring traffic lanes in which oncoming traffic is present in the neighbouring traffic lane and in which overtaking manoeuvres can take place.

Figure 1 illustrates schematically a motor vehicle 1 according to one embodiment of the present invention. The vehicle 1 given as an example is constituted by a heavy vehicle in the form of a lorry. Alternatively, the vehicle may be a bus or a car. The vehicle comprises a system I to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to the present invention. Figure 2 illustrates schematically a block diagram of a system I to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to one embodiment of the present invention.

The system I comprises an electronic control unit 100. The system I comprises means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle. The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle may include any suitable sensor means at all. The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle comprises, according to one variant, radar means. The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle comprises, according to one variant, camera means. The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle comprises, according to one variant, lidar means. The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle comprises, according to one variant, laser scanning means.

The means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle includes sensor means to detect on both sides of the leading vehicle in order to facilitate the detection of the presence of a vehicle behind the leading vehicle in a risk zone in association with the leading vehicle in traffic lanes to the right of the vehicle and in traffic lanes to the left of the vehicle. The leading vehicle comprises the means 1 10 to detect the presence of vehicles approaching the leading vehicle from behind. The system I comprises means 100, 120 to take the presence of a vehicle that is approaching the leading vehicle from behind in the said risk zone as a basis for taking measures during a change of traffic lane.

The system I comprises means 120 to take measures during change of traffic lane when it has been determined that a vehicle that is behind will become located in an action zone in a traffic lane that neighbours the leading vehicle, in which the leading vehicle is being driven.

The means 120 for taking measures comprises, according to one embodiment, means 122 to warn against a change of traffic lane when it has been determined that a vehicle that is behind will become located in an action zone in a traffic lane that neighbours the leading vehicle, in which the leading vehicle is being driven. The means 122 of warning against change of traffic lane may be constituted by any suitable warning means at all, such as visual warning means, audible warning means and/or tactile warning means. The visual warning means includes, according to one variant, a display unit and/or a blinking unit or equivalent. The audible warning means includes warning in the form of a voice message and/or warning in the form of a sound alarm. The tactile warning means includes an influence on the steering wheel of the vehicle in the form of vibration/motion and/or influence on the seat of the vehicle in the form of vibration and/or influence on a pedal such as the accelerator pedal or brake pedal.

The means 120 to take measures comprises, according to one embodiment, means 124 to prevent the leading vehicle from changing traffic lanes or to make it more difficult for the leading vehicle to change traffic lanes when it has been determined that a vehicle that is behind will become located in an action zone in a traffic lane that neighbours the leading vehicle, in which the leading vehicle is being driven. The means 124 to prevent or make it more difficult to change traffic lanes includes an influence on the control of the leading vehicle such as a change of steering wheel position in the direction towards the neighbouring traffic lane in which the risk is present. The means 120 for taking measures comprises, according to one variant, the electronic control unit 100.

The system I comprises means 130 to determine continuously the relative speed between the vehicles, i.e. the relative speed between the leading vehicle and vehicles behind whose presence has been determined. The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind comprises means to determine whether the vehicle that has been detected is approaching the leading vehicle, i.e. whether the vehicle that has been detected has a higher relative speed than the leading vehicle.

The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind comprises, according to one variant, radar means. The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind comprises, according to one variant, camera means. The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind comprises, according to one variant, lidar means. The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind comprises, according to one variant, laser scanning means. The means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind is comprised of, according to one variant, the means 1 10 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle. The system I comprises means 140 to, in the event that the relative speed that has been determined demonstrates that the said vehicles that are behind the leading vehicle are approaching it, to determine continuously when the said vehicles that are behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven. The means 140 to determine continuously when the said vehicles that are behind will become located in an action zone in a traffic lane that neighbours the vehicle in which the leading vehicle is being driven comprises, according to one variant, the means to determine continuously the relative speed v _re i, i.e. the difference in speed of the leading vehicle and a vehicle that is behind, and means to determine the distance S _tz to said vehicle that is behind. The time t _tz during which a vehicle that is located behind in the risk zone and that has been determined to be approaching the leading vehicle will be located in the action zone is determined, according to one variant, by:

The means 120 for taking measures is, according to one variant, arranged to be activated to take measures if t _tz = S _tz / v _re i < t _pre d, where t _pre d is an appropriate time that, that according to one variant, is of the magnitude of a few seconds, according to one variant in the interval 1 -5 seconds. The system I comprises means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place.

The means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place comprises means 152 to take into consideration when assessing the risk of change of traffic lane the relative speed between the leading vehicle and vehicles behind during the determination of how rapidly a change of traffic lane of the leading vehicle will take place.

The system I thus comprises means 152 to take into consideration when assessing the risk of change of traffic lane the relative speed between the leading vehicle and the vehicle behind during the determination of how rapidly a change of traffic lane of the leading vehicle will take place.

The means 152 to take into consideration when assessing the risk of change of traffic lane the relative speed between the leading vehicle and vehicles behind during the determination of how rapidly a change of traffic lane of the leading vehicle will take place comprises, according to one variant, the means to determine the relative speed.

The means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place comprises means 154 to take into consideration information about the situation of the leading vehicle in its traffic lane when determining how rapidly a change of traffic lane of the leading vehicle will take place.

The system I comprises in this case means 154 to take information about the situation of the leading vehicle in its traffic lane into consideration when determining how rapidly a change of traffic lane of the leading vehicle will take place. The means to take into consideration information about the situation of the leading vehicle in its traffic lane comprises means to determine the situation of the leading vehicle in its traffic lane. The means to determine the situation of the leading vehicle in its traffic lane includes means to determine the position of the leading vehicle in its traffic lane, which may include any suitable sensor means such as camera means and/or position- determining means, including map data and GPS. The means to determine the situation of the leading vehicle in its traffic lane includes means to determine the intention to change traffic lane, which may include means to determine whether the direction of travel indicator is activated and/or means to determine the steering wheel position. The means to determine the situation of the leading vehicle in its traffic lane includes, according to one variant, means to determine the speed of the vehicle. The means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place comprises, according to one variant, means to determine the angle to the road markings to neighbouring traffic lanes. The means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place comprises, according to one variant, means to determine the derivative of the distance to road markings to neighbouring traffic lanes.

According to one variant, a polynomial equation Y(x) = m + kx + ax ² +bx ³ is used, where Y(x) is the distance in the transverse direction to the road marking or neighbouring traffic lane, m is the current value of the distance to the road marking or neighbouring traffic lane, k is the angle to the road marking or neighbouring traffic lane, i.e. the gradient of m over the longitudinal distance, i.e. the derivative of m with respect to distance, a is the squared term in the polynomial equation Y(x), and b is the cubic term of the polynomial equation Y(x). According to one variant, the k-term is used, together with the speed of the leading vehicle, to determine when line/road markings that limit the traffic lane of the leading vehicle and neighbouring traffic lanes will be crossed such that the leading vehicle is located a certain distance, m_marg, into the neighbouring traffic lane/action zone, where the distance m_marg constitutes a distance into the neighbouring traffic lane/action zone at which measures should be taken. The time ti before the leading vehicle will be located in the action zone is determined in this case according to ti = -(m + m_marg)/(k ^* v) where v is the speed of the leading vehicle and where the side on which m is positive is considered. This is relevant only when k is negative, which corresponds to the vehicle approaching the neighbouring line/road marking to the neighbouring traffic lane/action zone, whereby ti will be positive. According to one variant, the linnit is linnited to a certain time, according to one variant this is a few seconds, such that a measure in the form of a warning is not to take place during the slightest sway or lurch of the leading vehicle. This may be, as mentioned, coupled also to the intention to change traffic lanes, which may include whether the direction of travel indicator is activated and/or a certain steering wheel position, whereby action is taken or a warning given solely when such an intention has been determined or when the time t1 is relatively short, for example shorter than 1 second.

Action in the form of, for example, a warning is arranged to take place if t _tz <= ti.

The system I comprises means 200a to determine, based on specifications concerning the extent of a defined traffic lane in which the leading vehicle is being driven, the extent of at least one neighbouring traffic lane based on continuously determined reference positions at the leading vehicle relative to the said neighbouring traffic lane in order to determine a risk zone extending a specified extent in the said neighbouring traffic lane backwards from the leading vehicle.

The system I consequently comprises means 200 to determine a risk zone extending a specified extent in the said neighbouring traffic lane backwards from the leading vehicle. The means 200 to determine a risk zone comprises the means 200a to determine the extent at the said neighbouring traffic lane.

The system I comprises means 200a to determine, based on specifications concerning the extent of a defined traffic lane in which the vehicle is being driven, the extent of at least one neighbouring traffic lane based on continuously determined reference positions at the vehicle relative to the said neighbouring traffic lane in order to determine an action zone extending a specified extent in the said neighbouring traffic lane alongside the vehicle. The distance that the action zone extends alongside the vehicle corresponds essentially to the longitudinal extent of the vehicle or somewhat greater than this.

Thus the system I comprises means 200 to determine an action zone extending a specified extent in the said neighbouring traffic lane alongside the vehicle. The means 200 to determine an action zone comprises the means to determine the extent at the said neighbouring traffic lane.

The means 200a to determine the extent to determine the risk zone and the means 200a to determine the extent to determine the action zone are constituted by, according to this example, the same means. Alternatively, it would be possible for the means to determine extent to determine the risk zone and the means to determine the extent to determine the action zone to be constituted by different means. The means 200 to determine the risk zone and the means 200 to determine the action zone are constituted by, according to this example, the same means. Alternatively, it would be possible for the means to determine the risk zone and the means to determine the action zone to be constituted by different means.

The means to determine the extent 200a at the said neighbouring traffic lane comprises means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes to the traffic lane of the leading vehicle.

The system I in this case comprises means 210 to determine continuously reference positions at the leading vehicle relative to the neighbouring traffic lane to the traffic lane of the leading vehicle.

The means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes comprises means 212 to determine continuously the reference positions at predetermined intervals.

According to one embodiment, the predetermined intervals are constituted by intervals of extent. The means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes consequently comprises, according to this embodiment, means 212a to determine continuously the reference positions at predetermined intervals of extent. The intervals of extent are constituted by, according to one variant, predetermined distances/extents through which the leading vehicle has travelled, where the relevant distance/extent is the same. The means 210 to determine reference positions is in this case arranged to determine continuously a reference position after each such distance/each such extent.

According to one embodiment, the predetermined intervals are constituted by intervals of time. The means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes consequently comprises, according to this embodiment, means 212b to determine continuously the reference positions at predetermined intervals of time. The intervals of time are constituted by predetermined intervals of time during which the leading vehicle has travelled, where each interval of time is the same. The means 210 to determine reference position is in this case arranged to determine continuously a reference position after each such interval of time.

The means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes comprises means 214 to determine parameters with respect to the travel of the leading vehicle. Parameters with respect to the travel of the leading vehicle include the rate of change of yaw angle and the speed of the leading vehicle.

The means 210 to determine extent at the said neighbouring traffic lanes consequently comprises means 214 to determine parameters with respect to the travel of the leading vehicle, which parameters include the rate of change of yaw angle and speed of the leading vehicle.

Thus the system I comprises means 200a to determine extent at the said neighbouring traffic lanes based on parameters with respect to the travel of the leading vehicle, which parameters include the rate of change of yaw angle and speed of the leading vehicle.

The rate of change of yaw angle is in this case used as a basis to determine whether, and the extent to which, the traffic lane in which the leading vehicle is being driven curves, whereby the assumption is made that neighbouring traffic lanes have corresponding curvatures.

The means 214 to determine parameters with respect to the travel of the leading vehicle comprises means 214a to determine the rate of change of yaw angle of the leading vehicle. The means 214a to determine the rate of change of yaw angle includes at least one gyroscope.

The means 214 to determine parameters with respect to the travel of the leading vehicle comprises means 214b to determine the speed of the leading vehicle. The means 214b to determine the speed of the vehicle comprises a speed gauge at the vehicle. The means 210 to determine continuously reference positions at the leading vehicle relative to the neighbouring traffic lanes comprises, according to one variant, navigation means 214c that includes positional data of the current position of the vehicle, and map data that comprises information about the degree of curvature of the relevant route. The means 214 to determine parameters with respect to the travel of the leading vehicle comprises the said navigation means 214c.

The navigation means 214c may be used as a supplement to the means 214a to determine the rate of change of yaw angle, to achieve redundancy. The determination of the rate of change of yaw angle in order to determine whether the traffic lane curves may be influenced by lurching of the leading vehicle, where information from the navigation means 214c concerning the degree of curvature of the traffic lane can be used to avoid erroneous assessments on the basis of such lurching . The navigation means 214c may be used also as an alternative to the means 214a to determine the rate of change of yaw angle.

The means 210a to determine extent of the said neighbouring traffic lanes consequently comprises, according to one variant, navigation means 214c that includes positional data of the current position of the vehicle, and map data that comprises information about the degree of curvature of the relevant route.

The system I comprises means 214a to determine the rate of change of yaw angle of the leading vehicle. The system I comprises means 214b to determine the speed of the leading vehicle.

The system I comprises the said navigation means 214c.

The means 210 to determine continuously reference positions at the leading vehicle relative to neighbouring traffic lanes includes means 216 to determine distance relative to the leading vehicle.

The means 21 6 to determine distance relative to the leading vehicle includes means 216a to determine line markings of neighbouring traffic lanes. The means 216a to determine line markings of neighbouring traffic lanes includes sensor means such as camera means. The means 216 to determine distance relative to the leading vehicle includes, according to one variant, sensor means. The said sensor means includes, according to one variant, camera means.

The means 216 to determine distance relative to the leading vehicle comprises, according to one variant, means 216b to determine virtual line markings of neighbouring traffic lanes. The means 216b to determine virtual line markings of neighbouring traffic lanes includes means to determine the width of traffic lanes in which the leading vehicle is travelling and/or neighbouring traffic lanes.

The means to determine the width of traffic lanes comprises, according to one variant, navigation means that includes map data with information about the width of traffic lanes at the relevant route, type of route, and information about the current position of the vehicle. The navigation means may be constituted by the navigation means 214c.

The means to determine the width of traffic lanes comprises, according to one variant, sensor means to determine the width of the traffic lane in which the leading vehicle is travelling, where, according to one variant, the width of the neighbouring traffic lane is assumed to be the same as the width of the traffic lane in which the leading vehicle is travelling . The means to determine the width of traffic lanes comprises, according to one variant, pre-determined stored information concerning the width of traffic lanes, which information may be stored in the electronic control unit 100.

The electronic control unit 100 is connected such that it exchanges signals over a link 1 1 with the means 1 10 to detect the presence of vehicles behind the leading vehicle in a risk zone that is associated with the leading vehicle. The electronic control unit 100 is arranged such that it receives through the link 1 1 a signal from the means 1 10 that represents vehicle data about the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle.

The electronic control unit 100 is connected such that it exchanges signals over a link 13 with the means 130 to determine continuously the relative speed between the leading vehicle and vehicles behind whose presence has been determined. The electronic control unit 100 is arranged to receive over the link 13 a signal from the means 130 that represents data for the relative speed between the leading vehicle and vehicles behind whose presence has been determined.

The electronic control unit 100 is connected such that it exchanges signals over a link 14 with the means 140 to, in the event that the relative speed that has been determined demonstrates that the said vehicles that are behind the leading vehicle are approaching it, to determine continuously when the said vehicle that is behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven. The electronic control unit 100 is arranged to receive a signal over the link 14 from the means 140 that represents time-based data for the time at which vehicles behind will become located within the action zone.

The electronic control unit 100 is connected such that it exchanges signals over a link 15 with the means 150 to determine how rapidly a change of traffic lane of the leading vehicle will takes place. The electronic control unit 100 is arranged to receive a signal over the link 15 from the means 150 to determine how rapidly a change of traffic lane of the leading vehicle will take place that represents time-based data for the time at which the leading vehicle will become located within the action zone during the change of traffic lane. The electronic control unit 100 is connected such that it exchanges signals over a link 20 with the means 200 to determine a risk zone extending backwards in neighbouring traffic lanes a specified extent from the leading vehicle. The electronic control unit 100 is arranged to receive a signal over the link 20 from the means 200 representing risk zone data for the risk zone that has been determined extending backwards in neighbouring traffic lanes from the leading vehicle.

The electronic control unit 100 is connected such that it exchanges signals over a link 20a with the means 200a to determine extent of the said neighbouring traffic lanes. The electronic control unit 100 is arranged to receive a signal over the link 20a from the means 200a representing extent data for the extent of neighbouring traffic lanes for the determination of the risk zone backwards from the leading vehicle.

The electronic control unit 100 is connected such that it exchanges signals over a link 20 with the means 200 to determine an action zone that extends in the said neighbouring traffic lanes a certain distance alongside the vehicle, essentially corresponding to the longitudinal extent of the vehicle. The electronic control unit 100 is arranged to receive a signal over the link 20 from the means 200 representing action zone data for the action zone that has been determined extending alongside the leading vehicle in neighbouring traffic lanes.

The electronic control unit 100 is connected such that it exchanges signals over a link 20a with the means 200a to determine extent of the said neighbouring traffic lanes. The electronic control unit 100 is arranged to receive a signal over the link 20a from the means 200a representing extent data for the extent of neighbouring traffic lanes for the determination of the action zone alongside the leading vehicle.

The electronic control unit 100 is connected such that it exchanges signals over a link 21 with the means 210 to determine continuously reference positions at the leading vehicle relative to traffic lanes neighbouring to the traffic lane of the leading vehicle. The electronic control unit 100 is arranged to receive a signal over the link 21 from the means 210 representing reference position data for reference positions to determine the extent of neighbouring traffic lanes for the determination of the risk zone backwards from the leading vehicle.

The electronic control unit 100 is connected such that it exchanges signals over a link 21 with the means 210 to determine continuously reference positions at the leading vehicle relative to traffic lanes neighbouring to the traffic lane of the leading vehicle. The electronic control unit 100 is arranged to receive a signal over the link 21 from the means 210 representing reference position data for the reference positions to determine the extent of neighbouring traffic lanes for the determination of the action zone alongside the leading vehicle. The electronic control unit 100 is connected such that it exchanges signals over a link 22 with the means 212 means to determine continuously the reference positions at predetermined intervals. The electronic control unit 100 is arranged to receive a signal over the link 22 from the means 21 2 representing reference position data in order to determine continuously the reference positions at predetermined intervals, where the interval may be an interval of extent determined by means of the means 212a or an interval of time determined by means of the means 212b. In this case, reference position data for intervals of extent or intervals of time are received over the link 22. According to variant that is not shown here, it would be possible for the electronic control unit 100 to receive reference position data for intervals of extent from the means 212a over one link, and reference position data for intervals of time from the means 212b over a second link.

The electronic control unit 100 is connected such that it exchanges signals over a link 24a with the means 214a to determine the rate of change of yaw angle of the leading vehicle. The electronic control unit 100 is arranged to receive a signal over the link 24a from the means 214a representing rate of change of yaw angle data for the determination of any curvature that the traffic lane in which the leading vehicle is being driven may have.

The electronic control unit 100 is connected such that it exchanges signals over a link 24b with the means 214b to determine the speed of the leading vehicle. The electronic control unit 100 is arranged to receive over the link 24b a signal from the means 214b that represents speed data for the speed of the leading vehicle. The electronic control unit 100 is connected such that it exchanges signals over a link 24c with the navigation means 214c. The electronic control unit 100 is arranged to receive a signal over the link 24c from the navigation means 214c representing map data for the width of the traffic lane in which the leading vehicle is being driven, including any curvature of the traffic lane that may be present.

The electronic control unit 100 is connected such that it exchanges signals over a link 26a with the means 216a to determine line markings of neighbouring traffic lanes. The electronic control unit 100 is arranged to receive a signal over the link 26a from the means 216a representing distance data for the distance to line markings of neighbouring traffic lanes.

The electronic control unit 100 is connected such that it exchanges signals over a link 26b with the means 216b to determine virtual line markings of neighbouring traffic lanes. The electronic control unit 100 is arranged to receive a signal over the link 26b from the means 216b representing distance data for the distance to virtual line markings of neighbouring traffic lanes.

The electronic control unit 100 is connected such that it exchanges signals over a link 12 with the means 120 in order to take measures during the change of traffic lane when it has been determined that a vehicle that is behind will become located in an action zone in a traffic lane that neighbours the leading vehicle, in which the leading vehicle is being driven. The electronic control unit 100 is arranged to transmit over the link 12 a signal to the means 120 representing action data, including warning data for the warning of change of traffic lane for the leading vehicle and/or impediment data in order to prevent or make more difficult change of traffic lane at the leading vehicle.

The electronic control unit 100 is arranged to process the said reference position data, rate of change of yaw angle data, speed data, and, where relevant, map data, distance data for line markings or virtual line markings in order to determine risk zone data for risk zones extending in neighbouring traffic lanes backwards from the leading vehicle.

The electronic control unit 100 is arranged to process the said reference position data, rate of change of yaw angle data, speed data, and, where relevant, map data, distance data for line markings or virtual line markings in order to determine action zone data for action zones extending in neighbouring traffic lanes alongside the leading vehicle.

The electronic control unit 100 is arranged to compare the said risk zone data with the said vehicle data for the presence of a vehicle behind the leading vehicle in order to determine whether the vehicle is present in the said risk zone.

The electronic control unit 100 is arranged to process the said data for relative speed between the leading vehicle and vehicles that have been determined to be behind it in order to determine whether the vehicle behind is approaching the leading vehicle. The electronic control unit 100 is arranged to process, if it has been determined that the vehicle in the risk zone behind is approaching, the said action zone data and time-based data for the time at which the vehicle behind will be located in the action zone.

The electronic control unit 100 is arranged to process the said time-based data for the time at which the leading vehicle will become located the action zone during change of traffic lane and to compare with time-based data for the time at which vehicles behind will be located in the action zone.

If it is determined by means of the electronic control unit 100 that the vehicle that is approaching the leading vehicle from behind will be present in the said action zone during the change of traffic lane of the leading vehicle, the control unit is arranged to transmit to the means 120 action data, including warning data for the warning of change of traffic lane for the leading vehicle and/or impediment data in order to prevent or make more difficult change of traffic lane at the leading vehicle. The reference positions are determined by means of the means 210 to determine reference positions continuously. The means 210 to determine reference positions continuously is determined, according to one embodiment, by means of the following equations: D _x (t) = D _x (t-t _s ) - cos (t _s ^* u))*ts ^* v (1 )

D _y (t) = D _y (t-t _s ) - sin (t _s ^* u))*ts ^* v (2) where the x-axis concerns positive values forwards in the direction of the leading vehicle, and the y-axis concerns positive values to the left in the direction of the leading vehicle. The following definitions apply for Equations (1 ) and (2) above: D denotes the distance [m] to line marking from a reference point at the leading vehicle 1 , where such a reference point at the leading vehicle may be constituted by, for example, the central point of the rear axle, the central point of the front axle, the central point of the front of the vehicle or equivalent, v denotes the speed of the leading vehicle [m/s], ω denotes the rate of change of yaw angle of the leading vehicle (rad/s), and t _s denotes the sampling time for the updating of reference positions.

During the continuous determination of the reference positions with predetermined intervals of extent, a new reference position is created regularly after a predetermined extent.

During the continuous determination of the reference positions with predetermined time intervals, a new reference position is created regularly after a predetermined time.

Figure 3 illustrates schematically the driving of a leading vehicle 1 on a roadway R1 with three neighbouring traffic lanes L1 , L2, L3, where reference positions relative to traffic lanes that are neighbouring to the vehicle have been determined. Figure 3 illustrates in this case a list of reference positions D _L AI , D _L BI ; D _L A2, DI_B2; D|_A3, D|_B3; D _L A4, D _L B4 determined by means of Equations (1 ) and (2) above. The reference positions D _L AI , D _L BI ; DLA2, D _L B2! D _L A3, D _L B3; D _L A4, D _L B4 according to Figure 4 have been determined by means of a system I according to the present invention.

An appropriate number N of reference positions D _L AI , D _L BI ; D _L A2, D _L B2! D _L A3, DLBS; D _L A4, D _L B4 in the form of reference points D _LA i , DLB-I ! D _LA 2, D _LB 2; D _LA 3, DLB3! D _L A4, DI_B4 is in this case determined. The distances to the line markings M 1 , M2 are here determined for the line marking M2 immediately to the left of the leading vehicle 1 and the next line marking M1 to the left, i.e. the line markings M1 , M2 defining the traffic lane L2 that is neighbour to the traffic lane L3 in which the leading vehicle 1 is travelling. This takes place continuously, whereby the oldest reference positions are overwritten when the desired number N of reference positions has been determined. The reference positions D _L AI , D _L A2, D _L A3, D _L A4, D _L B4 represent continuously determined distances to the line markings M2 immediately to the left of the leading vehicle 1 , and the reference positions D _L BI , D _L B2, D _L B3, D _L B4 distances to the line markings M1 to the left of the line markings M2. By means of the reference positions D _L AI , D _L BI ; DLA2, D _L B2! D _L A3, D _L B3; D _L A4, D _L B4 a risk zone is in this case continuously determined extending a determined extent backwards in the said neighbouring traffic lanes from the leading vehicle, and an action zone extending a determined extent in the said neighbouring traffic lane alongside the said vehicle, as is made clear by Figures 4a and 4b.

Figure 4a illustrates schematically the driving of a leading vehicle 1 on the roadway R1 in the direction of the arrow P1 according to Figure 3 with three neighbouring traffic lanes L1 , L2, L3 based on the reference positions that are continuously determined.

A vehicle 2 that is approaching the leading vehicle 1 from behind is being driven in the left traffic lane L1 in the direction of the arrow P2 and is located in a detection region A1 of a radar means with a certain range, where the detection region is directed from the left side of the leading vehicle and essentially directly backwards relative to its direction of travel.

A vehicle 3 that is approaching the leading vehicle 1 from behind is being driven in the direction of the arrow P3 in the traffic lane L2 that neighbours the leading vehicle 1 .

A risk zone Z1 is here determined based on continuously determined reference positions, where the risk zone extends in the neighbouring traffic lane L2 to the left of the leading vehicle 1 backwards from the leading vehicle 1 . An action zone Z3 is here determined based on continuously determined reference positions, where the action zone extends in the neighbouring traffic lane L2 to the left of the leading vehicle 1 alongside the leading vehicle 1 .

By means of the system I according to the present invention, it is determined that the approaching vehicle 2 that has been detected behind the leading vehicle 1 is not located in the risk zone Z1 that has been determined, whereby no measure based on the vehicle 2 that is approaching from behind in the left traffic lane L1 is taken during the change of traffic lane.

By means of the system I according to the present invention, it is determined that the approaching vehicle 3 that has been detected behind the leading vehicle 1 is located in the risk zone Z1 that has been determined, and that it will be located in the action zone if the leading vehicle were to change traffic lane to the neighbouring traffic lane L2, whereby measures based on the vehicle 3 that is approaching from behind in the neighbouring traffic lane L2 are taken during the change of traffic lane.

Figure 4b illustrates schematically the driving of a leading vehicle 1 on a roadway R1 in the direction of the arrow P1 with two neighbouring traffic lanes L1 , L2. A vehicle 2 that is approaching the leading vehicle 1 from behind is being driven in the right traffic lane L2 in the direction of the arrow P2 and is located at a distance behind the vehicle 1 in the traffic lane L2.

A vehicle 3 that is approaching the leading vehicle 1 from behind is being driven in the direction of the arrow P3 in the traffic lane L2 that neighbours the leading vehicle 1 and is located alongside, i.e. at essentially the same height as, the leading vehicle 1 .

A risk zone Z2 is here determined based on continuously determined reference positions, where the risk zone extends in the neighbouring traffic lane L2 to the right of the leading vehicle 1 backwards from the leading vehicle 1 . An action zone Z4 is here determined based on continuously determined reference positions, where the action zone extends in the neighbouring traffic lane L2 to the right of the leading vehicle 1 alongside the leading vehicle 1 . By means of the system I according to the present invention, it is determined that the approaching vehicle 2 that has been detected behind the leading vehicle 1 is located in the risk zone Z1 that has been determined, and that it will be located in the action zone if the leading vehicle were to change traffic lane to the neighbouring traffic lane L2, whereby measures based on the vehicle 2 that is approaching from behind in the neighbouring traffic lane L2 are taken during the change of traffic lane.

It is determined by means of the system I according to the present invention that the vehicle 3 is located in the action zone Z4 that has been determined, whereby measures are taken during change of traffic lane. The action zone Z3, Z4 according to Figures 4a and 4b that extends in the neighbouring traffic lane alongside the leading vehicle 1 is arranged to be a distance Z3a, Z4a corresponding to the length of the vehicle 1 or somewhat exceeding this. The risk zone Z1 , Z2 according to Figures 4a and 4b that extends in the neighbouring traffic lane backwards from the leading vehicle 1 may constitute an extension backwards from the action zone Z3, Z4 and extend backwards a distance Z1 b, Z2b, it may partially overlap the action zone in order subsequently to continue extending backwards a distance, or it may fully overlap the action zone in order subsequently to continue extending backwards a distance Z1 a, Z2a. It would be possible for the action zone Z3, Z4 to have a width that differs from the width of the risk zone Z1 , Z2 where the action zone is, according to one variant, narrower than the risk zone Z1 , Z2 that extends from the action zone Z3, Z4.

As is made clear by Figures 4a and 4b, the extent Z1 a, Z2a, Z1 b, Z2b with which the said risk zone is arranged to extend backwards in the said neighbouring traffic lane L2 from the said leading vehicle 1 is set to exceed the range A1 a, A2a for the detection of the said vehicle 2, 3 that is approaching the leading vehicle 1 from behind.

Figure 6 illustrates schematically a block diagram of a method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to one embodiment of the present invention. According to one embodiment, the method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes comprises a first step S1 . The presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle is detected in this step. According to one embodiment, the method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes comprises a second step S2. The relative speed between the vehicles is determined continuously in this step. According to one embodiment, the method to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes comprises a third step S3. It is determined in this step, in the event that the relative speed that has been determined demonstrates that the said vehicle that is behind the leading vehicle is continuously approaching it, when the said vehicle that is behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven.

With reference to Figure 7 , there is shown a drawing of a design of an arrangement 500. The control unit 100 that has been described with reference to Figure 3 can comprise in one execution the arrangement 500. The arrangement 500 comprises a non-transient memory 520, a data processing unit 510 and a read/write memory 550. The non-transient memory 520 has a first section of memory 530 in which a computer program, such as an operating system, is stored in order to control the function of the arrangement 500. Furthermore, the arrangement 500 comprises a bus controller, a serial communication port, I/O means, an A D converter, a unit for the input and transfer of time and date, an event counter and an interrupt controller (not shown in the drawing). The non-transient memory 520 has also a second section of memory 540.

There is provided a computer program P that comprises routines to assess the risk of change of traffic lane during the driving of a leading vehicle on a roadway with at least two neighbouring traffic lanes according to the innovative method. The program P comprises routines to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle. The program P comprises routines to determine continuously the relative speed between the vehicles. The program P comprises routines to determine continuously, in the event that the relative speed that has been determined demonstrates that the said vehicle that is behind the leading vehicle is continuously approaching it, when the said vehicle that is behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven. The program P may be stored in an executable form or in a compressed form in a memory 560 and/or a read/write memory 550. When it is described that the data processing unit 510 carries out a certain function, it is to be understood that the data processing unit 510 carries out a certain part of the program that is stored in the memory 560, or a certain part of the program that is stored in the read/write memory 550.

The data processing arrangement 510 can communicate with a data port 599 through a data bus 515. The non-transient memory 520 is intended for communication with the data processing unit 510 through a data bus 512. The separate memory 560 is intended to communicate with the data processing unit 510 through a data bus 51 1 . The read/write memory 550 is arranged to communicate with the data processing unit 510 through a data bus 514. Links associated with the control units 200; 300, for example, may be connected to the data port 599.

When data is received at the data port 599 it is temporarily stored in the second section of memory 540. When the data that has been received has been temporarily stored, the data processing unit 510 is prepared for the execution of code in a manner that has been described above. The signals that have been received at the data port 599 can be used by the arrangement 500 to detect the presence of a vehicle behind the leading vehicle in a risk zone that is associated with the leading vehicle. The signals received on the data port 599 can be used by the arrangement 500 to determine continuously the relative speed. The signals received at the data port 599 can be used by the arrangement 500 in order to, in the event that the relative speed that has been determined demonstrates that the said vehicle that is behind the leading vehicle is approaching it, determine continuously when the said vehicle that is behind will become located in an action zone in a traffic lane that neighbours the vehicle, in which the leading vehicle is being driven.

Parts of the methods described here may be carried out by the arrangement 500 with the aid of the data processing unit 510, which runs the program stored in the memory 560 or in the read/write memory 550. When the arrangement 500 runs the program, the method described here is executed.

The description above of the preferred embodiments of the present invention has been given for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the variants that have been described. Many modifications and variations will be obvious for one skilled in the arts. The embodiments have been selected and described in order to best describe the principles of the invention and its practical applications, and thus to make it possible for one skilled in the arts to understand the invention for various embodiments and with the various modifications that are appropriate for the intended use.