EP3423325A1

EP3423325A1 - Method and system for controlling the speed of a host vehicle along a road

Info

Publication number: EP3423325A1
Application number: EP17760390.9A
Authority: EP
Inventors: Assad ALAM; Christoffer NORÉN; Christian Larsson; Jonny Andersson
Original assignee: Scania CV AB
Current assignee: Scania CV AB
Priority date: 2016-03-02
Filing date: 2017-02-17
Publication date: 2019-01-09
Also published as: SE542264C2; WO2017151034A1; EP3423325A4; SE1650271A1

Abstract

The present invention relates to a method for controlling the speed of a host vehicle (1) along a road (R) taking a preceding vehicle (2) into account. The method comprises the steps of: detecting (S1) in a line of sight (LS) the direction of travel (T1) of the host vehicle (1) so as to 5 detect a preceding vehicle (2); determining whether the preceding vehicle (2) is deviating from the detected line of sight (LS), deviation comprising the preceding vehicle (2) disappearing from the detected line of sight (LS). The method further comprises the steps of: determining, if there is a deviation, the character of 10 the deviation; and controlling the speed of the host vehicle (1) based upon the thus determined character of said deviation.. The present invention also relates to a system for controlling the speed of a host vehicle along a road taking a preceding vehicle into account. The present invention also relates to a vehicle. The present invention also relates 15 to a computer program and a computer program product.

Description

METHOD AND SYSTEM FOR CONTROLLING THE SPEED OF A HOST

VEHICLE ALONG A ROAD

TECHNICAL FIELD The invention relates to a method for controlling the speed of a host vehicle along a road. The invention also relates to a system for controlling the speed of a host vehicle along a road. The invention also relates to a vehicle. The invention in addition relates to a computer program and a computer program product.

BACKGROUND ART

In order to optimize driving of a vehicle such as a truck the host vehicle is provided with adaptive cruise control wherein the speed of the host vehicle is adapted to a preceding vehicle at a certain distance ahead of the host vehicle by tracking the preceding vehicle using suitable detection means. It is however hard to track preceding vehicles in sharp curves. Therefore the most probable behaviour of the preceding target vehicle is predicted in the adaptive cruise control by suitable or optimal methods. This target prediction estimates the preceding vehicles movement when it is lost by the detection means. Because of the target prediction the behaviour of the adaptive cruise control feels slow and unresponsive in certain situations. During e.g. driving on a highway operation the situation that the preceding vehicle enters an off-ramp serving as a highway exit may occur, this situation resulting in the target prediction starting, since the preceding vehicle appears lost. KR20130022151 discloses an adaptive cruise control system wherein the lane of the preceding vehicle is determined by means of camera unit and a radar unit. It is further detected if the preceding vehicle deviates from the line of sight of the detector unit due to e.g. a curve or a slope.

There is however a need for improving controlling the speed of a host vehicle along a road where a preceding vehicle is taken into account.

OBJECTS OF THE INVENTION

An object of the present invention is to provide a method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account which improves control of the speed of the vehicle and hence control of driving of the vehicle.

Another object of the present invention is to provide a system for controlling the speed of a host vehicle along a road taking a preceding vehicle into account which improves control of the speed of the vehicle and hence control of driving of the vehicle.

SUMMARY OF THE INVENTION

These and other objects, apparent from the following description, are achieved by a method, a system, a vehicle, a computer program and a computer program product, as set out in the appended independent claims. Preferred embodiments of the method and the system are defined in appended dependent claims.

Specifically an object of the invention is achieved by a method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account. The method comprises the steps of: detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle; determining whether the preceding vehicle is deviating from the detected line of sight using a line sensor (in particular a camera), deviation comprising the preceding vehicle disappearing from the detected line of sight. The method further comprises the steps of: determining, if there is a deviation, the character of the deviation; and controlling the speed of the host vehicle based upon the thus determined character of said deviation.

The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises utilizing any suitable line sensor that can comprise one or more camera units and/or one or more Lidar units, i.e. laser scanner units, and/or one or more radar units. The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle thus comprises detecting in the direction of travel of the host vehicle so as to detect whether the preceding vehicle is in the line of sight of detection means, the line of sight essentially being in the direction of travel of the host vehicle. The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises detecting such that the host vehicle detects the preceding vehicle when it is in path of the preceding vehicle, i.e. in the same field so that only the preceding vehicle and not vehicles in adjacent lanes are covered to such an extent that it is not clear which vehicle to follow. The line of sight may possibly cover a certain additional lateral position such that it may be detected if a preceding vehicle is crossing the lanes for leaving or entering the lane of the road in which the host vehicle is travelling. Hereby it can be determined if the preceding vehicle is in path of the host vehicle. In particular the lane placement of the own vehicle can be compared to the lane placement of the vehicle in front of the own vehicle. Hereby an improved determination of a lane change of the vehicle in front can be achieved because the deviation of lane placement can be more easily detected and /or detected at an earlier point in time.

Controlling the speed of the host vehicle based upon the thus determined character of said deviation comprises adapting the speed of the vehicle. Adapting the speed of the vehicle comprises reducing the speed of the host vehicle, reduction of speed comprising activating brakes and/or free rolling, preferably with the drivetrain engaged, i.e. so called motoring, shifting gear for speed decrease. Adapting the speed of the vehicle comprises increasing the speed of the host vehicle, increase of speed comprising giving a torque demand of increased torque, e.g. giving gas, shifting gear for speed increase.

Hereby control of the speed of the vehicle and hence control of driving of the vehicle is improved in that more efficient control of the speed is facilitated wherein situations where the character of the deviation/disappearance of the preceding vehicle results in that the preceding vehicle will not continue in the same lane or same road as the host vehicle control of the speed of the host vehicle does not need to be simulated taking as if the preceding vehicle will reappear in the line of sight of the host vehicle. Thus unnecessary slow and unresponsive experience of the control of the speed of the vehicle, i.e. the cruise control, can be avoided. If it is determined that the character of the deviation of the preceding vehicle will likely result in the preceding vehicle reappearing the control of the speed of the vehicle is adapted to that situation. By thus controlling the speed of the vehicle use of autonomous vehicle is improved. By thus controlling the speed of the vehicle forming of an autonomous control strategy is facilitated.

According to an embodiment of the method the step of determining the character of the deviation comprises determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle. Hereby efficient control of the speed of the vehicle is obtained by thus control the speed based upon the character of the deviation of the preceding vehicle and the likelihood of a disappeared preceding vehicle reappearing or not. If it is likely that the preceding vehicle will not reappear in the line of sight the control of the preceding vehicle may be more quickly adapted to a new preceding vehicle if applicable.

According to an embodiment of the method the character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having changed or is changing lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope. A character of the deviation comprising a roundabout may result in the preceding vehicle reappearing or not and may require a certain adaption of the speed of the host vehicle. A character of the deviation comprising a road exit may result in the preceding vehicle not reappearing. A character of the deviation comprising the preceding vehicle changing lane may involve different control of the host vehicle, the host vehicle in one case adapting the speed due to the fact that the preceding vehicle is no longer in path of the host vehicle, and according to another variant the host vehicle changes lane to the lane of the preceding vehicle and continues to adapt the speed to the preceding vehicle. A character of the deviation comprising the host vehicle changing lane most likely will involve adapting the speed due to the fact that the preceding vehicle is no longer in path of the host vehicle. A character of the deviation comprising the preceding vehicle having entered a curve, the preceding vehicle having entered a slope will generally result in the preceding vehicle reappearing in the line of sight wherein the speed is controlled accordingly. A character of the deviation comprising the preceding vehicle having entered a slope will generally result in the preceding vehicle reappearing in the line of sight wherein the speed is controlled accordingly.

According to an embodiment the method comprises the step of determining the lane of the preceding vehicle and the lane of the host vehicle. The determination of the lane of the preceding vehicle and the lane of the host vehicle may be performed by means of detecting said lanes. The detection of the lane of the host vehicle and the detection of the lane of the preceding vehicle may be performed with the same detection means, i.e. same detector unit/units as for detecting in the line of sight the direction of travel of the host vehicle or with different detection means. The step of detecting the lane of the preceding vehicle and the step of detecting the lane of the host vehicle comprises utilizing any suitable detection means comprising one or more camera units and/or one or more Lidar units, i.e. laser scanner units, and/or one or more radar units. The step of determining the lane of the preceding vehicle may comprise receiving information from the preceding vehicle via vehicle-to-vehicle communication. The step of determining the lane of the host vehicle may comprise data of the position of the host vehicle and map data of information of the extension of the road along which the vehicle is travelling including lanes of the road along which the vehicle is travelling.

According to an embodiment the method comprises the step of determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle. The configuration of the road along which the host vehicle is travelling may comprise a roundabout, an exit from the road along which the host vehicle is travelling, number of lanes and change of number of lanes, a curve, a slope or the like. By thus determining the position of the host vehicle and extracting map information, i.e. map data of information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle the control of the speed is improved in that information of possible characters of deviation of the preceding vehicle is known beforehand wherein the speed may be controlled taking the information of the extension of the road into account. The information may thus comprise upcoming ramps/ road exits from which the preceding vehicle may exit the road, roundabouts, curves, change of number of lanes, slopes and the like that may or will result in the preceding vehicle disappearing from the line of sight, i.e. the detected direction of travel of the host vehicle.

According to an embodiment the method comprises the steps of establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. Hereby the intention of the preceding vehicle is known, or at least likely to be known, whereas the control of the speed of the vehicle can be further improved and more efficient thus avoiding any unnecessary adaption of to the speed of the preceding vehicle. Hereby quicker actions regarding control and where applicable adaption of the speed may be taken if it is communicated that the preceding vehicle will disappear and not reappear in the line of sight of the host vehicle. Specifically an object of the invention is achieved by a system for controlling the speed of a host vehicle along a road taking a preceding vehicle into account. The system comprises means for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle; and means for determining whether the preceding vehicle is deviating from the detected line of sight, deviation comprising the preceding vehicle disappearing from the detected line of sight. The system further comprises means for determining, if there is a deviation, the character of the deviation; and means for controlling the speed of the host vehicle based upon the thus determined character of said deviation. According to an embodiment of the system the means for determining the character of the deviation comprises means for determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle. According to an embodiment of the system the character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having changed or is changing lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope.

According to an embodiment the system comprises means for determining the lane of the preceding vehicle and means for determining the lane of the host vehicle. According to an embodiment the system comprises means for determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle. According to an embodiment the system comprises means for establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement; and means for receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle.

The system for controlling the speed of a host vehicle along a road taking a preceding vehicle into account is adapted to perform the methods as set out herein.

The system according to the invention has the advantages according to the corresponding method claims.

Specifically an object of the invention is achieved by a vehicle comprising a system as set out herein. Specifically an object of the invention is achieved by a computer program for controlling the speed of a host vehicle along a road taking a preceding vehicle into account, said computer program comprising program code which, when run on an electronic control unit or another computer connected to the electronic control unit, causes the electronic control unit to perform methods as set out herein.

Specifically an object of the invention is achieved by a computer program product comprising a digital storage medium storing the computer program.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention reference is made to the following detailed description when read in conjunction with the accompanying drawings, wherein like reference characters refer to like parts throughout the several views, and in which: Fig. 1 schematically illustrates a side view of a vehicle according to the present invention;

Fig. 2a schematically illustrates a plan view of a road with a road exit, a host vehicle travelling along the road trailing a preceding vehicle;

Fig. 2b schematically illustrates a plan view of a road with a curve, a host vehicle travelling along the road trailing a preceding vehicle;

Fig. 2c schematically illustrates a side view of a road with a slope, a host vehicle travelling along the road trailing a preceding vehicle;

Fig. 3a-f schematically illustrates a plan view of a road with three lanes, a host vehicle travelling in one of the lanes and a preceding vehicle is positioned in different lateral positions relative to the line of sight of the direction of travel of the host vehicle; Fig. 4 schematically illustrates a plan view of a road with a roundabout, a host vehicle travelling along the road trailing a preceding vehicle;

Fig. 5 schematically illustrates a block diagram of a system for controlling the speed of a host vehicle along a road taking a preceding vehicle into account according to an embodiment of the present invention;

Fig. 6 schematically illustrates a block diagram of a method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account according to an embodiment of the present invention; and

Fig. 7 schematically illustrates a computer according to an embodiment of the present invention.

DETAILED DESCRIPTION

Hereinafter the term "link" refers to a communication link which may be a physical connector, such as an optoelectronic communication wire, or a non- physical connector such as a wireless connection, for example a radio or microwave link.

Fig. 1 schematically illustrates a side view of a vehicle 1 according to the present invention. The exemplified vehicle 1 is a heavy vehicle in the shape of a truck. The vehicle according to the present invention could be any suitable vehicle such as a bus or a car. The vehicle according to the present invention could be an autonomous vehicle. The vehicle comprises a system I for controlling the speed of a host 1 vehicle along a road R taking a preceding vehicle into account.

Fig. 2a schematically illustrates a plan view of a road R with a road exit L1 e, a host vehicle 1 travelling along the road R trailing a preceding vehicle 2. The host vehicle 1 is detecting in a line of sight LS the direction of travel T1 of the host vehicle 1 so as to detect a preceding vehicle 2. The preceding vehicle has a direction of travel T2.

The preceding vehicle 2 has deviated from the line of sight LS and exited the road R at the road exit Li e. The deviation of the preceding vehicle 2 exiting the road R constitutes a character of deviation resulting in the preceding vehicle disappearing from the line of sight LS and not reappearing in the line of sight LS if the host vehicle 1 is continuing on along the road R. The direction of travel T2 of the preceding vehicle corresponds to the extension of the road exit L1 e which differs from the direction of travel T1 of the host vehicle 1 .

The speed of the host vehicle is controlled based upon the thus determined character of the deviation constituted by the vehicle having entered a road exit and disappearing and not reappearing.

Fig. 2b schematically illustrates a plan view of a road R with a curve, a host vehicle 1 travelling along the road R trailing a preceding vehicle 2.

The host vehicle 1 is detecting in a line of sight LS the direction of travel T1 of the host vehicle 1 so as to detect a preceding vehicle 2. The preceding vehicle has a direction of travel T2. The preceding vehicle 2 has deviated from the line of sight LS by entering a curve of the road R. The deviation of the preceding vehicle 2 entering the curve of the road R constitutes a character of deviation resulting in the preceding vehicle disappearing from the line of sight LS and reappearing in the line of sight LS. The direction of travel T2 of the preceding vehicle corresponds to the extension of the curve which differs from the direction of travel T1 of the host vehicle 1 . The speed of the host vehicle is controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 having entered a curve of the road and disappearing and reappearing.

Fig. 2c schematically illustrates a side view of a road R with a slope, a host vehicle 1 travelling along the road R trailing a preceding vehicle 2;

The host vehicle 1 is detecting in a line of sight LS the direction of travel T1 of the host vehicle 1 so as to detect a preceding vehicle 2. The preceding vehicle has a direction of travel T2. The preceding vehicle 2 has deviated from the line of sight LS by entering a slope of the road R. The deviation of the preceding vehicle 2 entering the slope of the road R constitutes a character of deviation resulting in the preceding vehicle disappearing from the line of sight LS and reappearing in the line of sight LS. The direction of travel T2 of the preceding vehicle corresponds to the extension of the slope which differs from the direction of travel T1 of the host vehicle 1 .

The speed of the host vehicle is controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 having entered a slope of the road and disappearing and reappearing. Fig. 3a-f schematically illustrates a plan view of a road R with three lanes L1 , L2, L3, a host vehicle 1 travelling in one of the lanes and a preceding vehicle 2 is positioned in different lateral positions relative to the line of sight LS of the direction of travel of the host vehicle 1 .

The host vehicle 1 is detecting in a line of sight LS the direction of travel T1 of the host vehicle 1 so as to detect a preceding vehicle 2. The preceding vehicle has a direction of travel T2. Fig. 3a illustrates the host vehicle 1 travelling in the same lane L2 as the preceding vehicle 2, the host vehicle 1 thus being in path of the preceding vehicle 2 and thus the control of the speed of the host vehicle 1 is based on the preceding vehicle in a conventional cruise control manner. Fig. 3b and 3d illustrates the host vehicle 1 travelling in the lane L2 and the preceding vehicle deviating such that it is in between lanes, in between lanes L2 and L3 in fig. 3b and in between lanes L2 and L1 in fig. 3d.

The deviation of the preceding vehicle 2 being laterally positioned in between lanes constitutes a character of deviation. If the preceding vehicle 2 is deviating in between lanes such that it is leaving the lane L2 in which the host vehicle 1 is travelling the speed of the host vehicle 1 may be controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 being in between lanes and disappearing. Hereby the control of the speed of the host vehicle 1 may be adapted already when the preceding vehicle is starting to disappear from the line of sight LS and thus efficient control is obtained.

If the preceding vehicle 2 is deviating in between lanes such that it is entering the lane L2 in which the host vehicle 1 is travelling the speed of the host vehicle 1 may be controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 being in between lanes and reappearing. Hereby the control of the speed of the host vehicle 1 may be adapted to the preceding vehicle already when the preceding vehicle is starting to appear/reappear in the line of sight LS and thus efficient control is obtained.

Fig. 3c and 3e illustrates the host vehicle 1 travelling in the lane L2 and the preceding vehicle deviating such that it has changed lane to an adjacent lane, lane L3 and in fig. 3c and lane L1 in fig. 3e. The deviation of the preceding vehicle 2 being laterally positioned in another lane than the lane of the road along which the host vehicle 1 is travelling constitutes a character of deviation.

The speed of the host vehicle 1 may be controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 having changed lane and disappearing and most likely not reappearing.

Fig. 3f illustrates the preceding vehicle 2 deviating due to the host vehicle 1 having changed lane from the lane 2 of the preceding vehicle to an adjacent lane L3, here left lane L3. The deviation of the preceding vehicle 2 being laterally positioned in another lane than the lane of the road along which the host vehicle 1 is travelling due to the host vehicle 1 changing lanes constitutes a character of deviation.

The speed of the host vehicle 1 may controlled based upon the thus determined character of the deviation constituted by the host vehicle 1 having changed lane and disappearing and most likely not reappearing.

Fig. 4 schematically illustrates a plan view of a road R with a roundabout RA, a host vehicle 1 travelling along the road R trailing a preceding vehicle 2.

The host vehicle 1 is detecting in a line of sight LS the direction of travel T1 of the host vehicle 1 so as to detect a preceding vehicle 2. The preceding vehicle has a direction of travel T2.

The preceding vehicle 2 has deviated from the line of sight LS by entering a roundabout RA of the road R. The deviation of the preceding vehicle 2 entering the roundabout RA of the road R constitutes a character of deviation resulting in the preceding vehicle disappearing from the line of sight LS. If the preceding vehicle will reappear again or not depends on whether the preceding vehicle 2 and the host vehicle 1 take the same route through and exits the roundabout RA at the same exit. The direction of travel T2 of the preceding vehicle corresponds to the extension of the roundabout RA at the current position of the preceding vehicle 2 which differs from the direction of travel T1 of the host vehicle 1 .

The speed of the host vehicle is controlled based upon the thus determined character of the deviation constituted by the preceding vehicle 2 having entered a roundabout RA of the road and disappearing and reappearing or disappearing and not reappearing.

Above, with reference to fig. 2a-c, 3a-f and fig. 4 different characters of deviation of a preceding vehicle 2 has been described. The deviation of the preceding vehicle 2 and the character of the deviation is determined in accordance with the present invention. The determination of the deviation of the preceding vehicle 2 and the character of the deviation may thus involve detecting in the line of sight of the direction of travel of the host vehicle 1 . The determination of the deviation of the preceding vehicle 2 and the character of the deviation may also involve for the host vehicle to establish contact with and receiving information from the preceding vehicle 2 regarding intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. The control may also involve determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle.

Fig. 5 schematically illustrates a system I for controlling the speed of a host vehicle along a road taking a preceding vehicle into account.

The system I comprises an electronic control unit 100.

The system I comprises means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle. The means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises any suitable detector unit. The means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises according to an embodiment one or more Lidar units, i.e. laser scanner units, and/or one or more camera units and/or one or more radar units. The means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises is arranged on the host vehicle driving along the road. The means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle is adapted to detect such that the host vehicle detects the preceding vehicle when it is in path of the preceding vehicle, i.e. in the same field so that only the preceding vehicle and not vehicles in adjacent lanes are covered to such an extent that it is not clear which vehicle to follow. The line of sight may possibly cover a certain additional lateral position such that it may be detected if a preceding vehicle is crossing the lanes for leaving or entering the lane of the road in which the host vehicle is travelling.

The system I comprises means 120 for determining whether the preceding vehicle is deviating from the detected line of sight, deviation comprising the preceding vehicle disappearing from the detected line of sight.

The means 120 for determining whether the preceding vehicle is deviating from the detected line of sight comprises the means 1 10 and the electronic control unit 100, wherein information from the means 1 10 of detected line of sight is processed by means of the electronic control unit 100 so as to determined possible deviation of the preceding vehicle.

The system I comprises means 130 for means for determining, if there is a deviation, the character of the deviation.

The means for determining the character of the deviation comprises means 132 for determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle.

The character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having or is changing changed lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope. The system I comprises means 140 for controlling the speed of the host vehicle based upon the thus determined character of said deviation.

The means 140 for controlling the speed of the host vehicle based upon the thus determined character of said deviation comprises control within a cruise control arrangement of the vehicle. The means 140 for controlling the speed comprises means for adapting the speed of the vehicle. The means for adapting the speed of the vehicle comprises means for reducing the speed of the host vehicle, reduction of speed comprising activating brakes and/or free rolling free rolling, preferably with the drivetrain engaged, i.e. so called motoring, shifting gear for speed decrease. The means for adapting the speed of the vehicle comprises means for increasing the speed of the host vehicle, increase of speed comprising giving a torque demand of increased torque, e.g. giving gas, shifting gear for speed increase.

The system I comprises means 150 for determining the lane of the preceding vehicle. The means 150 for determining the lane of the preceding vehicle comprises means 152 for detecting the lane of the preceding vehicle.

The means 152 for detecting the lane of the preceding vehicle is according to an embodiment comprised in or comprises the means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle.

The means 150 for determining the lane of the preceding vehicle comprises means 154 for receiving information from the preceding vehicle about the lane in which the preceding vehicle is travelling within a vehicle-to-vehicle communication arrangement. The means 154 is according to an embodiment comprised in the means 180 and means 190 described below.

The system I comprises means 160 for determining the lane of the host vehicle. The means 160 for determining the lane of the host vehicle comprises means 162 for detecting the lane of the host vehicle.

The means 162 for detecting the lane of the host vehicle is according to an embodiment comprised in or comprises the means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle.

The means 160 for determining the lane of the host vehicle comprises according to an embodiment means 164 for determining the current position of the host vehicle and means 166 for extracting map information of the road along which the vehicle is travelling comprising lanes of the road along which the vehicle is travelling. The means 164 and means 166 are according to an embodiment comprised in the means 170 described below.

The system I comprises means 1 70 for determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle.

The configuration of the road along which the host vehicle is travelling may comprise a roundabout, an exit from the road along which the host vehicle is travelling, number of lanes and change of number of lanes, a curve, a slope or the like.

The means 170 for determining the configuration of the road along which the host vehicle is travelling comprises means 172 for determining the current position of the host vehicle.

The means 172 for determining the position of the vehicle comprises according to an embodiment a global positioning system, GPS, for continuously determining the position of the vehicle along the road on which it is travelling.

The means 170 for determining the configuration of the road along which the host vehicle is travelling comprises means 174 for extracting map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle.

The means 174 for extracting map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle comprises according to an embodiment a map information unit comprising map data comprising information about the extension of the road along which the vehicle is travelling comprising information about possible characters of deviation of a preceding vehicle.

The system I comprises means 1 80 for establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement V2V. The other vehicle may comprise means 200 for receiving and communicating information, e.g. an electronic control unit or the like.

The system I comprises means 1 90 for receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. The preceding vehicle may comprise means 200 for establishing contact and communicating and receiving information, the means 200 comprising/constituting e.g. an electronic control unit or the like.

The electronic control unit 100 is operably connected to the means 1 10 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle via a link 10. The electronic control unit 100 is via the link 10 arranged to receive a signal from said means 1 10 representing detection data for the detected line of sight.

The electronic control unit 100 is operably connected to the means 120 for determining whether the preceding vehicle is deviating from the detected line of sight via a link 20a. The electronic control unit 100 is via the link 20a arranged to send a signal to said means 120 representing detection data for the detected line of sight.

The electronic control unit 100 is operably connected to the means 120 for determining whether the preceding vehicle is deviating from the detected line of sight via a link 20b. The electronic control unit 100 is via the link 20b arranged to receive a signal from said means 120 representing data for possible deviation comprising degree of deviation.

The electronic control unit 100 is operably connected to the means 130 for determining, if there is a deviation, the character of the deviation via a link 30a. The electronic control unit 100 is via the link 30a arranged to send a signal to said means 130 representing data for deviation comprising degree of deviation.

The electronic control unit 100 is operably connected to the means 130 for determining, if there is a deviation via a link 30b. The electronic control unit 100 is via the link 30b arranged to receive a signal from said means 130 representing data for character of the deviation. The electronic control unit 100 is operably connected to the means 132 for determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle via a link 32a. The electronic control unit 100 is via the link 32a arranged to send a signal to said means 130 representing data for d for character of the deviation.

The electronic control unit 100 is operably connected to the means 132 for determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle via a link 32b. The electronic control unit 100 is via the link 32b arranged to receive a signal from said means 130 representing data for. The electronic control unit 100 is operably connected to the means 140 for controlling the speed of the host vehicle based upon the thus determined character of said deviation via a link 40. The electronic control unit 100 is via the link 40 arranged to receive a signal from said means 140 representing data for controlling the speed of the host vehicle based upon the thus determined character of the deviation.

The electronic control unit 100 is operably connected to the means 150 for determining the lane of the preceding vehicle via a link 50. The electronic control unit 100 is via the link 50 arranged to receive a signal from said means 150 representing data for determined lane of the preceding vehicle. The electronic control unit 100 is operably connected to the means 152 for detecting the lane of the preceding vehicle of the preceding vehicle via a link 52. The electronic control unit 100 is via the link 52 arranged to receive a signal from said means 152 representing data for detected lane of the preceding vehicle. The electronic control unit 100 is operably connected to the means 154 for receiving information from the preceding vehicle about the lane in which the preceding vehicle is travelling within a vehicle-to-vehicle communication arrangement via a link 54. The electronic control unit 100 is via the link 54 arranged to receive a signal from said means 154 representing communication data from the preceding vehicle about determined lane of the preceding vehicle.

The electronic control unit 100 is operably connected to the means 160 for determining the lane of the host vehicle via a link 60. The electronic control unit 100 is via the link 60 arranged to receive a signal from said means 160 representing data for determined lane of the host vehicle.

The electronic control unit 100 is operably connected to the means 162 for detecting the lane of the host vehicle of the host vehicle via a link 62. The electronic control unit 100 is via the link 62 arranged to receive a signal from said means 162 representing data for detected lane of the host vehicle.

The electronic control unit 100 is operably connected to the means 164 for determining the current position of the host vehicle via a link 64. The electronic control unit 100 is via the link 64 arranged to receive a signal from said means 164 representing position data for current position of the host vehicle. The electronic control unit 100 is operably connected to the means 166 for extracting map information of the road along which the vehicle is travelling comprising lanes of the road along which the host vehicle is travelling via a link 66. The electronic control unit 100 is via the link 66 arranged to receive a signal from said means 166 representing data for lane along which the host vehicle is travelling.

The electronic control unit 100 is operably connected to the means 170 for determining the configuration of the road along which the host vehicle is travelling via a link 70. The electronic control unit 100 is via the link 70 arranged to receive a signal from said means 170 representing data for configuration of the road along which the host vehicle is travelling.

The electronic control unit 100 is operably connected to the means 172 for determining the current position of the host vehicle via a link 72. The electronic control unit 100 is via the link 72 arranged to receive a signal from said means 172 representing position data for position of the host.

The electronic control unit 100 is operably connected to the means 174 for extracting map information of the road along which the host vehicle is travelling via a link 74. The electronic control unit 100 is via the link 74 arranged to receive a signal from said means 174 representing data for possible characters of deviation of a preceding vehicle.

The electronic control unit 100 is operably connected to the means 1 80 means 180 for establishing contact with the preceding vehicle within a vehicle-to- vehicle communication arrangement via a link 80. The electronic control unit 100 is via the link 80 arranged to receive a signal from said means 1 80 representing data for establishing contact with the preceding vehicle. The electronic control unit 100 may also send data via the link 80.

The electronic control unit 100 is operably connected to the means 190 for receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle via a link 90. The electronic control unit 100 is via the link 90 arranged to receive a signal from said means 190 representing data about intention to deviate from the detected direction of travel of the host vehicle. The data comprises information about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. The electronic control unit 1 00 may also send data via the link 90. Fig. 4 schematically illustrates a block diagram of a method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account according to an embodiment of the present invention.

According to the embodiment the method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account comprises a step S1 . In this step it is detected in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle.

According to the embodiment the method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account comprises a step S2. In this step it is determined whether the preceding vehicle is deviating from the detected line of sight, deviation comprising the preceding vehicle disappearing from the detected line of sight.

According to the embodiment the method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account comprises a step S3, which is performed if there is a deviation, i.e. if the preceding vehicle is determined to deviate from the detected line of sight. In this step the character of the deviation is determined.

According to the embodiment the method for controlling the speed of a host vehicle along a road taking a preceding vehicle into account comprises a step S4. In this step the speed of the host vehicle is controlled based upon the thus determined character of said deviation.

Controlling the speed of the host vehicle based upon the thus determined character of said deviation comprises adapting the speed of the vehicle. Adapting the speed of the vehicle comprises reducing the speed of the host vehicle, reduction of speed comprising activating brakes and/or free rolling free rolling, preferably with the drivetrain engaged, i.e. so called motoring, shifting gear for speed decrease. Adapting the speed of the vehicle comprises increasing the speed of the host vehicle, increase of speed comprising giving a torque demand of increased torque, e.g. giving gas, shifting gear for speed increase.

The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises utilizing any suitable detection means comprising one or more camera units and/or one or more Lidar units, i.e. laser scanner units, and/or one or more radar units. The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle thus comprises detecting in the direction of travel of the host vehicle so as to detect whether the preceding vehicle is in the line of sight of detection means, the line of sight essentially being in the direction of travel of the host vehicle. The step of detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle comprises detecting such that the host vehicle detects the preceding vehicle when it is in path of the preceding vehicle, i.e. in the same field so that only the preceding vehicle and not vehicles in adjacent lanes are covered to such an extent that it is not clear which vehicle to follow. The line of sight may possibly cover a certain additional lateral position such that it may be detected if a preceding vehicle is crossing the lanes for leaving or entering the lane of the road in which the host vehicle is travelling. Hereby it can be determined if the preceding vehicle is in path of the host vehicle.

Hereby control of the speed of the vehicle and hence control of driving of the vehicle is improved in that more efficient control of the speed is facilitated wherein situations where the character of the deviation/disappearance of the preceding vehicle results in that the preceding vehicle will not continue in the same lane or same road as the host vehicle control of the speed of the host vehicle does not need to be simulated taking as if the preceding vehicle will reappear in the line of sight of the host vehicle. Thus unnecessary slow and unresponsive experience of the control of the speed of the vehicle, i.e. the cruise control, can be avoided. If it is determined that the character of the deviation of the preceding vehicle will likely result in the preceding vehicle reappearing the control of the speed of the vehicle is adapted to that situation. By thus controlling the speed of the vehicle use of autonomous vehicle is improved. By thus controlling the speed of the vehicle forming of an autonomous control strategy is facilitated. According to an embodiment of the method the step of determining the character of the deviation comprises determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle. Hereby efficient control of the speed of the vehicle is obtained by thus control the speed based upon the character of the deviation of the preceding vehicle and the likelihood of a disappeared preceding vehicle reappearing or not. If it is likely that the preceding vehicle will not reappear in the line of sight the control of the preceding vehicle may be more quickly adapted to a new preceding vehicle if applicable.

According to an embodiment of the method the character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having changed or is changing lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope. A character of the deviation comprising a roundabout may result in the preceding vehicle reappearing or not and may require a certain adaption of the speed of the host vehicle. A character of the deviation comprising the preceding vehicle changing lane may involve different control of the host vehicle, the host vehicle in one case adapting the speed due to the fact that the preceding vehicle is no longer in path of the host vehicle, and according to another variant the host vehicle changes lane to the lane of the preceding vehicle and continues to adapt the speed to the preceding vehicle. A character of the deviation comprising the host vehicle changing lane most likely will involve adapting the speed due to the fact that the preceding vehicle is no longer in path of the host vehicle. A character of the deviation comprising the preceding vehicle having entered a curve, the preceding vehicle having entered a slope will generally result in the preceding vehicle reappearing in the line of sight wherein the speed is controlled accordingly. A character of the deviation comprising the preceding vehicle having entered a slope will generally result in the preceding vehicle reappearing in the line of sight wherein the speed is controlled accordingly.

According to an embodiment the method comprises the step of determining the lane of the preceding vehicle and the lane of the host vehicle. The determination of the lane of the preceding vehicle and the lane of the host vehicle may be performed by means of detecting said lanes. The detection of the lane of the host vehicle and the detection of the lane of the preceding vehicle may be performed with the same detection means, i.e. same detector unit/units as for detecting in the line of sight the direction of travel of the host vehicle or with different detection means. The step of detecting the lane of the preceding vehicle and the step of detecting the lane of the host vehicle comprises utilizing any suitable detection means comprising one or more line sensors such as one or more camera units and/or one or more Lidar units, i.e. laser scanner units, and/or one or more radar units. Using a line sensor provides the advantage that the lane placement of the own vehicle and another vehicle can be compared and thereby a determination of a lane change can be improved. The step of determining the lane of the preceding vehicle may comprise receiving information from the preceding vehicle via vehicle-to- vehicle communication. The step of determining the lane of the host vehicle may comprise data of the position of the host vehicle and map data of information of the extension of the road along which the vehicle is travelling including lanes of the road along which the vehicle is travelling.

According to an embodiment the method comprises the steps of establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. Hereby the intention of the preceding vehicle is known, or at least likely to be known, whereas the control of the speed of the vehicle can be further improved and more efficient thus avoiding any unnecessary adaption of to the speed of the preceding vehicle. Hereby quicker actions regarding control and where applicable adaption of the speed may be taken if it is communicated that the preceding vehicle will disappear and not reappear in the line of sight of the host vehicle. With reference to figure 5, a diagram of an apparatus 500 is shown. The control unit 100 described with reference to fig. 5 may according to an embodiment comprise apparatus 500. Apparatus 500 comprises a non-volatile memory 520, a data processing device 510 and a read/write memory 550. Non-volatile memory 520 has a first memory portion 530 wherein a computer program, such as an operating system, is stored for controlling the function of apparatus 500. Further, apparatus 500 comprises a bus controller, a serial communication port, l/O-means, an A/D-converter, a time date entry and transmission unit, an event counter and an interrupt controller (not shown). Non-volatile memory 520 also has a second memory portion 540.

A computer program P is provided comprising routines for controlling the speed of a host vehicle along a road taking a preceding vehicle into account according to an embodiment of the present invention. The program P comprises routines for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle. The program P comprises routines for determining whether the preceding vehicle is deviating from the detected line of sight, deviation comprising the preceding vehicle disappearing from the detected line of sight. The program P comprises routines for determining, if there is a deviation, the character of the deviation. The program P comprises routines for controlling the speed of the host vehicle based upon the thus determined character of said deviation. The routines for determining the character of the deviation comprises determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle. The character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having changed or is changing lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope. The program P comprises routines for determining the lane of the preceding vehicle and the lane of the host vehicle. The program P comprises routines for determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle. The program P comprises routines for establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement. The program P comprises routines for receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle. The computer program P may be stored in an executable manner or in a compressed condition in a separate memory 560 and/or in read/write memory 550. When it is stated that data processing device 510 performs a certain function it should be understood that data processing device 510 performs a certain part of the program which is stored in separate memory 560, or a certain part of the program which is stored in read/write memory 550.

Data processing device 510 may communicate with a data communications port 599 by means of a data bus 515. Non-volatile memory 520 is adapted for communication with data processing device 510 via a data bus 512. Separate memory 560 is adapted for communication with data processing device 510 via a data bus 51 1 . Read/write memory 550 is adapted for communication with data processing device 510 via a data bus 514. To the data communications port 599 e.g. the links connected to the control units 100 may be connected.

When data is received on data port 599 it is temporarily stored in second memory portion 540. When the received input data has been temporarily stored, data processing device 510 is set up to perform execution of code in a manner described above. The signals received on data port 599 can be used by apparatus 500 for detecting in a line of sight the direction of travel of the host vehicle so as to detect a preceding vehicle. The signals received on data port 599 can be used by apparatus 500 for determining whether the preceding vehicle is deviating from the detected line of sight, deviation comprising the preceding vehicle disappearing from the detected line of sight. The signals received on data port 599 can be used by apparatus 500 for determining, if there is a deviation, the character of the deviation. The signals received on data port 599 can be used by apparatus 500 for and controlling the speed of the host vehicle based upon the thus determined character of said deviation. The signals used by apparatus 500 for determining the character of the deviation comprises determining whether the deviation is likely to result in the preceding vehicle disappearing and not reappearing in the detected direction of travel of the host vehicle or whether the deviation is likely to result in the preceding vehicle reappearing in the detected direction of travel of the host vehicle. The character of the deviation comprises any of: preceding vehicle having entered a roundabout, the preceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changing lane, the host vehicle having changed or is changing lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope. The signals received on data port 599 can be used by apparatus 500 for determining the lane of the preceding vehicle and the lane of the host vehicle. The signals received on data port 599 can be used by apparatus 500 for determining the configuration of the road along which the host vehicle is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle. The signals received on data port 599 can be used by apparatus 500 for establishing contact with the preceding vehicle within a vehicle-to-vehicle communication arrangement. The signals received on data port 599 can be used by apparatus 500 for receiving information from the preceding vehicle about intention to deviate from the detected direction of travel of the host vehicle resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel of the host vehicle.

Parts of the methods described herein can be performed by apparatus 500 by means of data processing device 510 running the program stored in separate memory 560 or read/write memory 550. When apparatus 500 runs the program, parts of the methods described herein are executed.

The foregoing description of the preferred embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications, thereby enabling others skilled in the art to understand the invention for various embodiments and with the various modifications as are suited to the particular use contemplated.

Claims

1 . A method for controlling the speed of a host vehicle (1 ) along a road (R) taking a preceding vehicle (2) into account, comprising the steps of: detecting (S1 ) in a line of sight (LS) the direction of travel (T1 ) of the host vehicle (1 ) so as to detect a preceding vehicle (2); determining whether the preceding vehicle (2) is deviating from the detected line of sight (LS), characterized by the steps of:

- determining using a line sensor, if there is a deviation, the character of the deviation; and

- controlling the speed of the host vehicle (1 ) based upon the thus determined character of said deviation.

2. A method according to claim 1 , wherein the step of determining the character of the deviation comprises determining whether the deviation is likely to result in the preceding vehicle (2) disappearing and not reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ) or whether the deviation is likely to result in the preceding vehicle (2) reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ).

3. A method according to claim 1 or 2, wherein the character of the deviation comprises any of: preceding vehicle (2) having entered a roundabout (RA), the preceding vehicle (2) having entered an exit from the road (R) along which the host vehicle (1 ) is travelling, the preceding vehicle (2) having changed or is changing lane, the host vehicle (1 ) having changed or is changing lane, the preceding vehicle (2) having entered a curve, the preceding vehicle (2) having entered a slope.

4. A method according to any of claims 1 -3, comprising the step of determining the lane of the preceding vehicle (2) and the lane of the host vehicle (1 ).

5. A method according to any of claims 1 -4, comprising the step of determining the configuration of the road (R) along which the host vehicle (1 ) is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road (R) along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle (2).

6. A method according to any of claims 1 -5, comprising the steps of establishing contact with the preceding vehicle (2) within a vehicle-to-vehicle communication arrangement (V2V); receiving information from the preceding vehicle (2) about intention to deviate from the detected direction of travel (T1 ) of the host vehicle (1 ) resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ).

7. A method according to any of claims 1 -6, wherein the line sensor used is a camera.

8. A system (I) for controlling the speed of a host vehicle (1 ) along a road (R) taking a preceding vehicle (2) into account, comprising means (1 10) for detecting in a line of sight (LS) the direction of travel (T1 ) of the host vehicle (1 ) so as to detect a preceding vehicle (2); means (120) for determining whether the preceding vehicle (2) is deviating from the detected line of sight (LS), characterized by line sensor means (130) for determining, if there is a deviation, the character of the deviation; and means (140) for controlling the speed of the host vehicle (1 ) based upon the thus determined character of said deviation.

9. A system od according to claim 8, wherein the means (130) for determining the character of the deviation comprises means (132) for determining whether the deviation is likely to result in the preceding vehicle (2) disappearing and not reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ) or whether the deviation is likely to result in the preceding vehicle (2) reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ).

10. A system according to claim 8 or 9, wherein the character of the deviation comprises any of: preceding vehicle (2) having entered a roundabout (RA), the preceding vehicle (2) having entered an exit (Li e) from the road (R) along which the host vehicle (1 ) is travelling, the preceding vehicle (2) having changed or is changing lane, the host vehicle (1 ) having changed or is changing lane, the preceding vehicle (2) having entered a curve, the preceding vehicle (2) having entered a slope.

1 1 . A system according to any of claims 8-10, comprising means (150) for determining the lane of the preceding vehicle (2) and means (160) for determining the lane of the host vehicle (1 ).

12. A system according to of claims 8-1 1 , comprising means (170) for determining the configuration of the road (R) along which the host vehicle (1 ) is travelling based on a determined current position of the host vehicle and extracted map information of the extension of the road (R) along which the vehicle is travelling so as to determine possible characters of deviation of a preceding vehicle (2).

13. A system according to of claims 8-12, comprising means for establishing contact with the preceding vehicle (2) within a vehicle-to-vehicle communication arrangement (V2V); and means for receiving information from the preceding vehicle (2) about intention to deviate from the detected direction of travel (T1 ) of the host vehicle (1 ) resulting in disappearing and not reappearing or disappearing and reappearing in the detected direction of travel (T1 ) of the host vehicle (1 ).

14. A system according to any of claims 8 - 13, wherein the line sensor is a camera.

15. A vehicle (1 ) comprising a system (I) according to any of claims 8-14.

16. A computer program (P) for controlling the speed of a host vehicle (1 ), said computer program (P) comprising program code which, when run on an electronic control unit (100) or another computer (500) connected to the electronic control unit (100), causes the electronic control unit to perform the steps according to claim 1 -7.

17. A computer program product comprising a digital storage medium storing the computer program according to claim 16.