SE1650271A1

SE1650271A1 - Method and system for controlling the speed of a host vehicle along a road

Info

Publication number: SE1650271A1
Application number: SE1650271A
Authority: SE
Inventors: Alam Assad; Norén Christoffer; Larsson Christian; Andersson Jonny
Original assignee: Scania Cv Ab
Priority date: 2016-03-02
Filing date: 2016-03-02
Publication date: 2017-09-03
Also published as: SE542264C2; EP3423325A4; WO2017151034A1; EP3423325A1

Abstract

The present invention relates to a method for controlling driving of a vehicle along a road. The method comprises the steps of: tracking (S1) one or more vehicles along the road ahead of said vehicle; determining (S2) a historic trail of the vehicle being tracked; and following (S3) a thus determined historic trail during driving of the vehicle.The present invention also relates to a system for controlling driving of a vehicle along a road. The present invention also relates to a vehicle. The present invention also relates to a computer program and a computer program product.(Fig. 4)

Description

I\/IETHOD AND SYSTEM FOR CONTROLLING THE SPEED OF A HOSTVEHICLE ALONG A ROAD TECHNICAL FIELD The invention relates to a method for controlling the speed of a host vehiclealong a road according to the preamble of claim 1. The invention also relatesto a system for controlling the speed of a host vehicle along a road. Theinvention also relates to a vehicle. The invention in addition relates to acomputer program and a computer program product.

BACKG ROUND ART ln order to optimize driving of a vehicle such as a truck the host vehicle isprovided with adaptive cruise control wherein the speed of the host vehicle isadapted to a preceding vehicle at a certain distance ahead of the host vehicleby tracking the preceding vehicle using suitable detection means. lt ishowever hard to track preceding vehicles in sharp curves. Therefore the mostprobable behaviour of the preceding target vehicle is predicted in theadaptive cruise control by suitable or optimal methods. This target predictionestimates the preceding vehicles movement when it is lost by the detection meanS.

Because of the target prediction the behaviour of the adaptive cruise controlfeels slow and unresponsive in certain situations. During e.g. driving on ahighway operation the situation that the preceding vehicle enters an off-rampserving as a highway exit may occur, this situation resulting in the targetprediction starting, since the preceding vehicle appears lost.

KF¶20130022151 discloses an adaptive cruise control system wherein the lane of the preceding vehicle is determined by means of camera unit and a radar unit. lt 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 thespeed of a host vehicle along a road taking a preceding vehicle into accountwhich 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 controllingthe speed of a host vehicle along a road taking a preceding vehicle intoaccount 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, areachieved by a method, a system, a vehicle, a computer program and acomputer 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 controllingthe speed of a host vehicle along a road taking a preceding vehicle intoaccount. The method comprises the steps of: detecting in a line of sight thedirection 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, deviation comprising the preceding vehicle disappearing from thedetected line of sight. The method further comprises the steps of:determining, if there is a deviation, the character of the deviation; andcontrolling the speed of the host vehicle based upon the thus determinedcharacter of said deviation.

The step of detecting in a line of sight the direction of travel of the hostvehicle so as to detect a preceding vehicle comprises utilizing any suitabledetection means comprising one or more camera units and/or one or moreLidar units, i.e. laser scanner units, and/or one or more radar units. The stepof detecting in a line of sight the direction of travel of the host vehicle so as todetect a preceding vehicle thus comprises detecting in the direction of travelof the host vehicle so as to detect whether the preceding vehicle is in the lineof sight of detection means, the line of sight essentially being in the directionof travel of the host vehicle. The step of detecting in a line of sight thedirection of travel of the host vehicle so as to detect a preceding vehiclecomprises detecting such that the host vehicle detects the preceding vehiclewhen it is in path of the preceding vehicle, i.e. in the same field so that onlythe preceding vehicle and not vehicles in adjacent lanes are covered to suchan extent that it is not clear which vehicle to follow. The line of sight maypossibly cover a certain additional lateral position such that it may bedetected if a preceding vehicle is crossing the lanes for leaving or enteringthe 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.

Controlling the speed of the host vehicle based upon the thus determinedcharacter of said deviation comprises adapting the speed of the vehicle.Adapting the speed of the vehicle comprises reducing the speed of the hostvehicle, reduction of speed comprising activating brakes and/or free rolling,preferably with the drivetrain engaged, i.e. so called motoring, shifting gearfor 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 thevehicle is improved in that more efficient control of the speed is facilitatedwherein situations where the character of the deviation/disappearance of thepreceding vehicle results in that the preceding vehicle will not continue in thesame lane or same road as the host vehicle control of the speed of the hostvehicle does not need to be simulated taking as if the preceding vehicle willreappear in the line of sight of the host vehicle. Thus unnecessary slow andunresponsive experience of the control of the speed of the vehicle, i.e. thecruise control, can be avoided. lf it is determined that the character of thedeviation of the preceding vehicle will likely result in the preceding vehiclereappearing the control of the speed of the vehicle is adapted to thatsituation. By thus controlling the speed of the vehicle use of autonomousvehicle is improved. By thus controlling the speed of the vehicle forming of anautonomous control strategy is facilitated.

According to an embodiment of the method the step of determining thecharacter of the deviation comprises determining whether the deviation islikely to result in the preceding vehicle disappearing and not reappearing inthe detected direction of travel of the host vehicle or whether the deviation islikely to result in the preceding vehicle reappearing in the detected directionof travel of the host vehicle. Hereby efficient control of the speed of thevehicle is obtained by thus control the speed based upon the character of thedeviation of the preceding vehicle and the likelihood of a disappearedpreceding vehicle reappearing or not. lf it is likely that the preceding vehiclewill 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 deviationcomprises any of: preceding vehicle having entered a roundabout, thepreceding vehicle having entered an exit from the road along which the host vehicle is travelling, the preceding vehicle having changed or is changinglane, the host vehicle having changed or is changing lane, the precedingvehicle having entered a curve, the preceding vehicle having entered a slope.A character of the deviation comprising a roundabout may result in thepreceding vehicle reappearing or not and may require a certain adaption ofthe speed of the host vehicle. A character of the deviation comprising a roadexit may result in the preceding vehicle not reappearing. A character of thedeviation comprising the preceding vehicle changing lane may involvedifferent control of the host vehicle, the host vehicle in one case adapting thespeed due to the fact that the preceding vehicle is no longer in path of thehost vehicle, and according to another variant the host vehicle changes laneto the lane of the preceding vehicle and continues to adapt the speed to thepreceding vehicle. A character of the deviation comprising the host vehiclechanging lane most likely will involve adapting the speed due to the fact thatthe preceding vehicle is no longer in path of the host vehicle. A character ofthe deviation comprising the preceding vehicle having entered a curve, thepreceding vehicle having entered a slope will generally result in thepreceding vehicle reappearing in the line of sight wherein the speed iscontrolled accordingly. A character of the deviation comprising the precedingvehicle having entered a slope will generally result in the preceding vehiclereappearing in the line of sight wherein the speed is controlled accordingly.

According to an embodiment the method comprises the step of determiningthe lane of the preceding vehicle and the lane of the host vehicle. Thedetermination of the lane of the preceding vehicle and the lane of the hostvehicle may be performed by means of detecting said lanes. The detection ofthe lane of the host vehicle and the detection of the lane of the precedingvehicle may be performed with the same detection means, i.e. same detectorunit/units as for detecting in the line of sight the direction of travel of the hostvehicle or with different detection means. The step of detecting the lane ofthe 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/orone or more radar units. The step of determining the |ane of the precedingvehicle may comprise receiving information from the preceding vehicle viavehicle-to-vehicle communication. The step of determining the |ane of thehost vehicle may comprise data of the position of the host vehicle and mapdata of information of the extension of the road along which the vehicle istravelling including lanes of the road along which the vehicle is travelling.

According to an embodiment the method comprises the step of determiningthe configuration of the road along which the host vehicle is travelling basedon a determined current position of the host vehicle and extracted mapinformation of the extension of the road along which the vehicle is travellingso as to determine possible characters of deviation of a preceding vehicle.The configuration of the road along which the host vehicle is travelling maycomprise a roundabout, an exit from the road along which the host vehicle istravelling, number of lanes and change of number of lanes, a curve, a slopeor the like. By thus determining the position of the host vehicle and extractingmap information, i.e. map data of information of the extension of the roadalong which the vehicle is travelling so as to determine possible characters ofdeviation of a preceding vehicle the control of the speed is improved in thatinformation of possible characters of deviation of the preceding vehicle isknown beforehand wherein the speed may be controlled taking theinformation of the extension of the road into account. The information maythus comprise upcoming ramps/ road exits from which the preceding vehiclemay exit the road, roundabouts, curves, change of number of lanes, slopesand the like that may or will result in the preceding vehicle disappearing fromthe line of sight, i.e. the detected direction of travel of the host vehicle.

According to an embodiment the method comprises the steps of establishingcontact with the preceding vehicle within a vehicle-to-vehicle communicationarrangement 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 thedetected direction of travel of the host vehicle. Hereby the intention of thepreceding vehicle is known, or at least likely to be known, whereas thecontrol of the speed of the vehicle can be further improved and more efficientthus avoiding any unnecessary adaption of to the speed of the precedingvehicle. Hereby quicker actions regarding control and where applicableadaption of the speed may be taken if it is communicated that the precedingvehicle 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 controllingthe speed of a host vehicle along a road taking a preceding vehicle intoaccount. The system comprises means for detecting in a line of sight thedirection of travel of the host vehicle so as to detect a preceding vehicle; andmeans for determining whether the preceding vehicle is deviating from thedetected line of sight, deviation comprising the preceding vehicledisappearing from the detected line of sight. The system further comprisesmeans 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 thecharacter of the deviation comprises means for determining whether thedeviation is likely to result in the preceding vehicle disappearing and notreappearing in the detected direction of travel of the host vehicle or whetherthe deviation is likely to result in the preceding vehicle reappearing in thedetected direction of travel of the host vehicle.

According to an embodiment of the system the character of the deviationcomprises any of: preceding vehicle having entered a roundabout, thepreceding vehicle having entered an exit from the road along which the hostvehicle is travelling, the preceding vehicle having changed or is changinglane, the host vehicle having changed or is changing lane, the precedingvehicle having entered a curve, the preceding vehicle having entered a slope.

According to an embodiment the system comprises means for determiningthe lane of the preceding vehicle and means for determining the lane of thehost vehicle.

According to an embodiment the system comprises means for determiningthe configuration of the road along which the host vehicle is travelling basedon a determined current position of the host vehicle and extracted mapinformation of the extension of the road along which the vehicle is travellingso as to determine possible characters of deviation of a preceding vehicle.

According to an embodiment the system comprises means for establishingcontact with the preceding vehicle within a vehicle-to-vehicle communicationarrangement; and means for receiving information from the preceding vehicleabout intention to deviate from the detected direction of travel of the hostvehicle resulting in disappearing and not reappearing or disappearing andreappearing in the detected direction of travel of the host vehicle.

The system for controlling the speed of a host vehicle along a road taking apreceding 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 asystem as set out herein.

Specifically an object of the invention is achieved by a computer program forcontrolling the speed of a host vehicle along a road taking a precedingvehicle into account, said computer program comprising program codewhich, when run on an electronic control unit or another computer connectedto the electronic control unit, causes the electronic control unit to performmethods 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 thefollowing detailed description when read in conjunction with theaccompanying 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 hostvehicle travelling along the road trailing a preceding vehicle; Fig. 2b schematically illustrates a plan view of a road with a curve, a hostvehicle travelling along the road trailing a preceding vehicle; Fig. 2c schematically illustrates a side view of a road with a slope, a hostvehicle travelling along the road trailing a preceding vehicle; Fig. 3a-f schematically illustrates a plan view of a road with three lanes, ahost vehicle travelling in one of the lanes and a preceding vehicle ispositioned in different lateral positions relative to the line of sight of thedirection of travel of the host vehicle; Fig. 4 schematically illustrates a plan view of a road with a roundabout, ahost vehicle travelling along the road trailing a preceding vehicle; Fig. 5 schematically illustrates a block diagram of a system for controlling thespeed 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 thespeed 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 aphysical 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 thepresent invention. The exemplified vehicle 1 is a heavy vehicle in the shapeof a truck. The vehicle according to the present invention could be anysuitable vehicle such as a bus or a car. The vehicle according to the presentinvention could be an autonomous vehicle. The vehicle comprises a system Ifor 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 L1e,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 T1of 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 theroad R at the road exit L1e. The deviation of the preceding vehicle 2 exitingthe 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 11 of sight LS if the host vehicle 1 is continuing on along the road R. Thedirection of travel T2 of the preceding vehicle corresponds to the extension ofthe road exit L1e which differs from the direction of travel T1 of the hostvehicle 1.

The speed of the host vehicle is controlled based upon the thus determinedcharacter of the deviation constituted by the vehicle having entered a roadexit and disappearing and not reappearing.

Fig. 2b schematically illustrates a plan view of a road R with a curve, a hostvehicle 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 T1of the host vehicle 1 so as to detect a preceding vehicle 2. The precedingvehicle has a direction of travel T2.

The preceding vehicle 2 has deviated from the line of sight LS by entering acurve of the road R. The deviation of the preceding vehicle 2 entering thecurve of the road R constitutes a character of deviation resulting in thepreceding vehicle disappearing from the line of sight LS and reappearing inthe line of sight LS. The direction of travel T2 of the preceding vehiclecorresponds to the extension of the curve which differs from the direction oftravel T1 of the host vehicle 1.

The speed of the host vehicle is controlled based upon the thus determinedcharacter 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 hostvehicle 1 travelling along the road R trailing a preceding vehicle 2; 12 The host vehicle 1 is detecting in a line of sight LS the direction of travel T1of the host vehicle 1 so as to detect a preceding vehicle 2. The precedingvehicle has a direction of travel T2.

The preceding vehicle 2 has deviated from the line of sight LS by entering aslope of the road R. The deviation of the preceding vehicle 2 entering theslope of the road R constitutes a character of deviation resulting in thepreceding vehicle disappearing from the line of sight LS and reappearing inthe line of sight LS. The direction of travel T2 of the preceding vehiclecorresponds to the extension of the slope which differs from the direction oftravel T1 of the host vehicle 1.

The speed of the host vehicle is controlled based upon the thus determinedcharacter of the deviation constituted by the preceding vehicle 2 havingentered 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 vehicle2 is positioned in different lateral positions relative to the line of sight LS ofthe direction of travel of the host vehicle 1.

Fig. 3a illustrates the host vehicle 1 travelling in the same lane L2 as thepreceding vehicle 2, the host vehicle 1 thus being in path of the precedingvehicle 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 thepreceding vehicle deviating such that it is in between lanes, in between lanesL2 and L3 in fig. 3b and in between lanes L2 and L1 in fig. 3d. 13 The deviation of the preceding vehicle 2 being laterally positioned in betweenlanes constitutes a character of deviation. lf the preceding vehicle 2 is deviating in between lanes such that it is leavingthe lane L2 in which the host vehicle 1 is travelling the speed of the hostvehicle 1 may be controlled based upon the thus determined character of thedeviation constituted by the preceding vehicle 2 being in between lanes anddisappearing. Hereby the control of the speed of the host vehicle 1 may beadapted already when the preceding vehicle is starting to disappear from theline of sight LS and thus efficient control is obtained. lf the preceding vehicle 2 is deviating in between lanes such that it is enteringthe lane L2 in which the host vehicle 1 is travelling the speed of the hostvehicle 1 may be controlled based upon the thus determined character of thedeviation constituted by the preceding vehicle 2 being in between lanes andreappearing. Hereby the control of the speed of the host vehicle 1 may beadapted to the preceding vehicle already when the preceding vehicle isstarting to appear/reappear in the line of sight LS and thus efficient control isobtained.

Fig. 3c and 3e illustrates the host vehicle 1 travelling in the lane L2 and thepreceding vehicle deviating such that it has changed lane to an adjacentlane, lane L3 and in fig. 3c and lane L1 in fig. 3e.

The deviation of the preceding vehicle 2 being laterally positioned in anotherlane 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 thusdetermined character of the deviation constituted by the preceding vehicle 2 having changed lane and disappearing and most likely not reappearing. 14 Fig. 3f illustrates the preceding vehicle 2 deviating due to the host vehicle 1having changed lane from the lane 2 of the preceding vehicle to an adjacentlane L3, here left lane L3.

The deviation of the preceding vehicle 2 being laterally positioned in anotherlane 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 thusdetermined character of the deviation constituted by the host vehicle 1 havingchanged 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 preceding vehicle 2 has deviated from the line of sight LS by entering aroundabout RA of the road R. The deviation of the preceding vehicle 2entering the roundabout RA of the road R constitutes a character of deviationresulting in the preceding vehicle disappearing from the line of sight LS. lf thepreceding vehicle will reappear again or not depends on whether thepreceding vehicle 2 and the host vehicle 1 take the same route through andexits the roundabout RA at the same exit. The direction of travel T2 of thepreceding vehicle corresponds to the extension of the roundabout RA at thecurrent position of the preceding vehicle 2 which differs from the direction oftravel T1 of the host vehicle 1.

The speed of the host vehicle is controlled based upon the thus determinedcharacter of the deviation constituted by the preceding vehicle 2 havingentered 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 ofdeviation of a preceding vehicle 2 has been described. The deviation of thepreceding vehicle 2 and the character of the deviation is determined inaccordance with the present invention. The determination of the deviation ofthe preceding vehicle 2 and the character of the deviation may thus involvedetecting in the line of sight of the direction of travel of the host vehicle 1. Thedetermination of the deviation of the preceding vehicle 2 and the character ofthe deviation may also involve for the host vehicle to establish contact withand receiving information from the preceding vehicle 2 regarding intention todeviate from the detected direction of travel of the host vehicle resulting indisappearing and not reappearing or disappearing and reappearing in thedetected direction of travel of the host vehicle. The control may also involvedetermining the configuration of the road along which the host vehicle istravelling based on a determined current position of the host vehicle andextracted map information of the extension of the road along which thevehicle is travelling so as to determine possible characters of deviation of apreceding 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 110 for detecting in a line of sight thedirection of travel of the host vehicle so as to detect a preceding vehicle.

The means 110 for detecting in a line of sight the direction of travel of thehost vehicle so as to detect a preceding vehicle comprises any suitabledetector unit. The means 110 for detecting in a line of sight the direction oftravel of the host vehicle so as to detect a preceding vehicle comprisesaccording 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 110 for detecting in a line of sight the direction of travel of the host vehicle so 16 as to detect a preceding vehicle comprises is arranged on the host vehicledriving along the road. The means 110 for detecting in a line of sight thedirection of travel of the host vehicle so as to detect a preceding vehicle isadapted to detect such that the host vehicle detects the preceding vehiclewhen it is in path of the preceding vehicle, i.e. in the same field so that onlythe preceding vehicle and not vehicles in adjacent lanes are covered to suchan extent that it is not clear which vehicle to follow. The line of sight maypossibly cover a certain additional lateral position such that it may bedetected if a preceding vehicle is crossing the lanes for leaving or enteringthe lane of the road in which the host vehicle is travelling.

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

The means 120 for determining whether the preceding vehicle is deviatingfrom the detected line of sight comprises the means 110 and the electroniccontrol unit 100, wherein information from the means 110 of detected line ofsight is processed by means of the electronic control unit 100 so as todetermined possible deviation of the preceding vehicle.

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

The means for determining the character of the deviation comprises means132 for determining whether the deviation is likely to result in the precedingvehicle disappearing and not reappearing in the detected direction of travel ofthe host vehicle or whether the deviation is likely to result in the precedingvehicle reappearing in the detected direction of travel of the host vehicle.

The character of the deviation comprises any of: preceding vehicle havingentered a roundabout, the preceding vehicle having entered an exit from theroad along which the host vehicle is travelling, the preceding vehicle havingchanged or is changing lane, the host vehicle having or is changing changed 17 lane, the preceding vehicle having entered a curve, the preceding vehicle having entered a slope.

The system l comprises means 140 for controlling the speed of the hostvehicle based upon the thus determined character of said deviation.

The means 140 for controlling the speed of the host vehicle based upon thethus determined character of said deviation comprises control within a cruisecontrol arrangement of the vehicle. The means 140 for controlling the speedcomprises means for adapting the speed of the vehicle. The means foradapting the speed of the vehicle comprises means for reducing the speed ofthe host vehicle, reduction of speed comprising activating brakes and/or freerolling free rolling, preferably with the drivetrain engaged, i.e. so calledmotoring, shifting gear for speed decrease. The means for adapting thespeed of the vehicle comprises means for increasing the speed of the hostvehicle, 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 precedingvehicle.

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 toan embodiment comprised in or comprises the means 110 for detecting in aline 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 comprisesmeans 154 for receiving information from the preceding vehicle about thelane in which the preceding vehicle is travelling within a vehicle-to-vehiclecommunication arrangement. The means 154 is according to an embodiment comprised in the means 180 and means 190 described below. 18 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 means162 for detecting the lane of the host vehicle.

The means 162 for detecting the lane of the host vehicle is according to anembodiment comprised in or comprises the means 110 for detecting in a lineof sight the direction of travel of the host vehicle so as to detect a precedingvehicle.

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

The system I comprises means 170 for determining the configuration of theroad along which the host vehicle is travelling based on a determined currentposition of the host vehicle and extracted map information of the extension ofthe 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 maycomprise a roundabout, an exit from the road along which the host vehicle istravelling, number of lanes and change of number of lanes, a curve, a slopeor the like.

The means 170 for determining the configuration of the road along which thehost vehicle is travelling comprises means 172 for determining the currentposition 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 19 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 thehost vehicle is travelling comprises means 174 for extracting map informationof 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 roadalong which the vehicle is travelling so as to determine possible characters ofdeviation of a preceding vehicle comprises according to an embodiment amap information unit comprising map data comprising information about theextension of the road along which the vehicle is travelling comprisinginformation about possible characters of deviation of a preceding vehicle.

The system I comprises means 180 for establishing contact with thepreceding vehicle within a vehicle-to-vehicle communication arrangementV2V. 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 190 for receiving information from thepreceding vehicle about intention to deviate from the detected direction oftravel of the host vehicle resulting in disappearing and not reappearing ordisappearing and reappearing in the detected direction of travel of the hostvehicle.

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 110 fordetecting 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 110 representing detection data for the detected line of sight.

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

The electronic control unit 100 is operably connected to the means 120 fordetermining whether the preceding vehicle is deviating from the detected lineof sight via a link 20b. The electronic control unit 100 is via the link 20barranged to receive a signal from said means 120 representing data forpossible deviation comprising degree of deviation.

The electronic control unit 100 is operably connected to the means 130 fordetermining, if there is a deviation, the character of the deviation via a link30a. The electronic control unit 100 is via the link 30a arranged to send asignal to said means 130 representing data for deviation comprising degreeof deviation.

The electronic control unit 100 is operably connected to the means 130 fordetermining, if there is a deviation via a link 30b. The electronic control unit100 is via the link 30b arranged to receive a signal from said means 130representing data for character of the deviation.

The electronic control unit 100 is operably connected to the means 132 fordetermining whether the deviation is likely to result in the preceding vehicledisappearing and not reappearing in the detected direction of travel of thehost vehicle or whether the deviation is likely to result in the precedingvehicle reappearing in the detected direction of travel of the host vehicle via alink 32a. The electronic control unit 100 is via the link 32a arranged to send asignal to said means 130 representing data for d for character of the deviation. 21 The electronic control unit 100 is operably connected to the means 132 fordetermining whether the deviation is likely to result in the preceding vehicledisappearing and not reappearing in the detected direction of travel of thehost vehicle or whether the deviation is likely to result in the precedingvehicle reappearing in the detected direction of travel of the host vehicle via alink 32b. The electronic control unit 100 is via the link 32b arranged to receivea signal from said means 130 representing data for.

The electronic control unit 100 is operably connected to the means 140 forcontrolling the speed of the host vehicle based upon the thus determinedcharacter of said deviation via a link 40. The electronic control unit 100 is viathe link 40 arranged to receive a signal from said means 140 representingdata for controlling the speed of the host vehicle based upon the thusdetermined character of the deviation.

The electronic control unit 100 is operably connected to the means 150 fordetermining the lane of the preceding vehicle via a link 50. The electroniccontrol unit 100 is via the link 50 arranged to receive a signal from saidmeans 150 representing data for determined lane of the preceding vehicle.

The electronic control unit 100 is operably connected to the means 152 fordetecting the lane of the preceding vehicle of the preceding vehicle via a link52. The electronic control unit 100 is via the link 52 arranged to receive asignal from said means 152 representing data for detected lane of thepreceding vehicle.

The electronic control unit 100 is operably connected to the means 154 forreceiving information from the preceding vehicle about the lane in which thepreceding vehicle is travelling within a vehicle-to-vehicle communicationarrangement via a link 54. The electronic control unit 100 is via the link 54arranged to receive a signal from said means 154 representingcommunication data from the preceding vehicle about determined lane of the preceding vehicle. 22 The electronic control unit 100 is operably connected to the means 160 fordetermining the lane of the host vehicle via a link 60. The electronic controlunit 100 is via the link 60 arranged to receive a signal from said means 160representing data for determined lane of the host vehicle.

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

The electronic control unit 100 is operably connected to the means 164 fordetermining the current position of the host vehicle via a link 64. Theelectronic control unit 100 is via the link 64 arranged to receive a signal fromsaid means 164 representing position data for current position of the hostvehicle.

The electronic control unit 100 is operably connected to the means 166 forextracting map information of the road along which the vehicle is travellingcomprising lanes of the road along which the host vehicle is travelling via alink 66. The electronic control unit 100 is via the link 66 arranged to receive asignal 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 fordetermining the configuration of the road along which the host vehicle istravelling via a link 70. The electronic control unit 100 is via the link 70arranged to receive a signal from said means 170 representing data forconfiguration of the road along which the host vehicle is travelling.

The electronic control unit 100 is operably connected to the means 172 fordetermining the current position of the host vehicle via a link 72. Theelectronic control unit 100 is via the link 72 arranged to receive a signal fromsaid means 172 representing position data for position of the host. 23 The electronic control unit 100 is operably connected to the means 174 forextracting map information of the road along which the host vehicle istravelling via a link 74. The electronic control unit 100 is via the link 74arranged to receive a signal from said means 174 representing data forpossible characters of deviation of a preceding vehicle.

The electronic control unit 100 is operably connected to the means 180means 180 for establishing contact with the preceding vehicle within avehicle-to-vehicle communication arrangement via a link 80. The electroniccontrol unit 100 is via the link 80 arranged to receive a signal from saidmeans 180 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 forreceiving information from the preceding vehicle about intention to deviatefrom the detected direction of travel of the host vehicle resulting indisappearing and not reappearing or disappearing and reappearing in thedetected direction of travel of the host vehicle via a link 90. The electroniccontrol unit 100 is via the link 90 arranged to receive a signal from saidmeans 190 representing data about intention to deviate from the detecteddirection of travel of the host vehicle. The data comprises information aboutintention to deviate from the detected direction of travel of the host vehicleresulting in disappearing and not reappearing or disappearing andreappearing in the detected direction of travel of the host vehicle. The electronic control unit 100 may also send data via the link 90.

Fig. 4 schematically illustrates a block diagram of a method for controlling thespeed 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 hostvehicle along a road taking a preceding vehicle into account comprises a 24 step S1. ln 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 hostvehicle along a road taking a preceding vehicle into account comprises astep S2. ln this step it is determined whether the preceding vehicle isdeviating 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 hostvehicle along a road taking a preceding vehicle into account comprises astep S3, which is performed if there is a deviation, i.e. if the preceding vehicleis determined to deviate from the detected line of sight. ln this step the character of the deviation is determined.

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

Controlling the speed of the host vehicle based upon the thus determinedcharacter of said deviation comprises adapting the speed of the vehicle.Adapting the speed of the vehicle comprises reducing the speed of the hostvehicle, reduction of speed comprising activating brakes and/or free rollingfree rolling, preferably with the drivetrain engaged, i.e. so called motoring,shifting gear for speed decrease. Adapting the speed of the vehiclecomprises increasing the speed of the host vehicle, increase of speedcomprising 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 hostvehicle so as to detect a preceding vehicle comprises utilizing any suitabledetection 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 todetect a preceding vehicle thus comprises detecting in the direction of travelof the host vehicle so as to detect whether the preceding vehicle is in the lineof sight of detection means, the line of sight essentially being in the directionof travel of the host vehicle. The step of detecting in a line of sight thedirection of travel of the host vehicle so as to detect a preceding vehiclecomprises detecting such that the host vehicle detects the preceding vehiclewhen it is in path of the preceding vehicle, i.e. in the same field so that onlythe preceding vehicle and not vehicles in adjacent lanes are covered to suchan extent that it is not clear which vehicle to follow. The line of sight maypossibly cover a certain additional lateral position such that it may bedetected if a preceding vehicle is crossing the lanes for leaving or enteringthe lane of the road in which the host vehicle is travelling. Hereby it can bedetermined if the preceding vehicle is in path of the host vehicle.

According to an embodiment of the method the step of determining thecharacter of the deviation comprises determining whether the deviation is 26 likely to result in the preceding vehicle disappearing and not reappearing inthe detected direction of travel of the host vehicle or whether the deviation islikely to result in the preceding vehicle reappearing in the detected directionof travel of the host vehicle. Hereby efficient control of the speed of thevehicle is obtained by thus control the speed based upon the character of thedeviation of the preceding vehicle and the likelihood of a disappearedpreceding vehicle reappearing or not. lf it is likely that the preceding vehiclewill not reappear in the line of sight the control of the preceding vehicle maybe more quickly adapted to a new preceding vehicle if applicable.

According to an embodiment of the method the character of the deviationcomprises any of: preceding vehicle having entered a roundabout, thepreceding vehicle having entered an exit from the road along which the hostvehicle is travelling, the preceding vehicle having changed or is changinglane, the host vehicle having changed or is changing lane, the precedingvehicle having entered a curve, the preceding vehicle having entered a slope.A character of the deviation comprising a roundabout may result in thepreceding vehicle reappearing or not and may require a certain adaption ofthe speed of the host vehicle. A character of the deviation comprising thepreceding vehicle changing lane may involve different control of the hostvehicle, the host vehicle in one case adapting the speed due to the fact thatthe preceding vehicle is no longer in path of the host vehicle, and accordingto another variant the host vehicle changes lane to the lane of the precedingvehicle and continues to adapt the speed to the preceding vehicle. Acharacter of the deviation comprising the host vehicle changing lane mostlikely will involve adapting the speed due to the fact that the precedingvehicle is no longer in path of the host vehicle. A character of the deviationcomprising the preceding vehicle having entered a curve, the precedingvehicle having entered a slope will generally result in the preceding vehiclereappearing in the line of sight wherein the speed is controlled accordingly. Acharacter of the deviation comprising the preceding vehicle having entered a 27 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 determiningthe lane of the preceding vehicle and the lane of the host vehicle. Thedetermination of the lane of the preceding vehicle and the lane of the hostvehicle may be performed by means of detecting said lanes. The detection ofthe lane of the host vehicle and the detection of the lane of the precedingvehicle may be performed with the same detection means, i.e. same detectorunit/units as for detecting in the line of sight the direction of travel of the hostvehicle or with different detection means. The step of detecting the lane ofthe preceding vehicle and the step of detecting the lane of the host vehiclecomprises utilizing any suitable detection means comprising one or morecamera units and/or one or more Lidar units, i.e. laser scanner units, and/orone or more radar units. The step of determining the lane of the precedingvehicle may comprise receiving information from the preceding vehicle viavehicle-to-vehicle communication. The step of determining the lane of thehost vehicle may comprise data of the position of the host vehicle and mapdata 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 determiningthe configuration of the road along which the host vehicle is travelling basedon a determined current position of the host vehicle and extracted mapinformation of the extension of the road along which the vehicle is travellingso as to determine possible characters of deviation of a preceding vehicle.The configuration of the road along which the host vehicle is travelling maycomprise a roundabout, an exit from the road along which the host vehicle istravelling, number of lanes and change of number of lanes, a curve, a slopeor the like. By thus determining the position of the host vehicle and extractingmap information, i.e. map data of information of the extension of the roadalong which the vehicle is travelling so as to determine possible characters of 28 deviation of a preceding vehicle the control of the speed is improved in thatinformation of possible characters of deviation of the preceding vehicle isknown beforehand wherein the speed may be controlled taking theinformation of the extension of the road into account. The information maythus comprise upcoming ramps/ road exits from which the preceding vehiclemay exit the road, roundabouts, curves, change of number of lanes, slopesand the like that may or will result in the preceding vehicle disappearing fromthe line of sight, i.e. the detected direction of travel of the host vehicle.

According to an embodiment the method comprises the steps of establishingcontact with the preceding vehicle within a vehicle-to-vehicle communicationarrangement receiving information from the preceding vehicle about intentionto deviate from the detected direction of travel of the host vehicle resulting indisappearing and not reappearing or disappearing and reappearing in thedetected direction of travel of the host vehicle. Hereby the intention of thepreceding vehicle is known, or at least likely to be known, whereas thecontrol of the speed of the vehicle can be further improved and more efficientthus avoiding any unnecessary adaption of to the speed of the precedingvehicle. Hereby quicker actions regarding control and where applicableadaption of the speed may be taken if it is communicated that the precedingvehicle 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. Thecontrol unit 100 described with reference to fig. 5 may according to anembodiment comprise apparatus 500. Apparatus 500 comprises a non-volatile memory 520, a data processing device 510 and a read/write memory550. Non-volatile memory 520 has a first memory portion 530 wherein acomputer program, such as an operating system, is stored for controlling thefunction of apparatus 500. Further, apparatus 500 comprises a bus controller,a serial communication port, l/O-means, an A/D-converter, a time date entryand transmission unit, an event counter and an interrupt controller (not shown). Non-volatile memory 520 also has a second memory portion 540. 29 A computer program P is provided comprising routines for controlling thespeed of a host vehicle along a road taking a preceding vehicle into accountaccording to an embodiment of the present invention. The program Pcomprises routines for detecting in a line of sight the direction of travel of thehost vehicle so as to detect a preceding vehicle. The program P comprisesroutines for determining whether the preceding vehicle is deviating from thedetected line of sight, deviation comprising the preceding vehicledisappearing from the detected line of sight. The program P comprisesroutines for determining, if there is a deviation, the character of the deviation.The program P comprises routines for controlling the speed of the hostvehicle based upon the thus determined character of said deviation. Theroutines for determining the character of the deviation comprises determiningwhether the deviation is likely to result in the preceding vehicle disappearingand not reappearing in the detected direction of travel of the host vehicle orwhether the deviation is likely to result in the preceding vehicle reappearingin the detected direction of travel of the host vehicle. The character of thedeviation comprises any of: preceding vehicle having entered a roundabout,the preceding vehicle having entered an exit from the road along which thehost vehicle is travelling, the preceding vehicle having changed or ischanging lane, the host vehicle having changed or is changing lane, thepreceding vehicle having entered a curve, the preceding vehicle havingentered a slope. The program P comprises routines for determining the laneof the preceding vehicle and the lane of the host vehicle. The program Pcomprises routines for determining the configuration of the road along whichthe host vehicle is travelling based on a determined current position of thehost vehicle and extracted map information of the extension of the road alongwhich the vehicle is travelling so as to determine possible characters ofdeviation of a preceding vehicle. The program P comprises routines forestablishing contact with the preceding vehicle within a vehicle-to-vehiclecommunication arrangement. The program P comprises routines forreceiving 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 thedetected direction of travel of the host vehicle. The computer program P maybe 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 functionit should be understood that data processing device 510 performs a certainpart of the program which is stored in separate memory 560, or a certain partof the program which is stored in read/write memory 550.

Data processing device 510 may communicate with a data communicationsport 599 by means of a data bus 515. Non-volatile memory 520 is adaptedfor communication with data processing device 510 via a data bus 512.Separate memory 560 is adapted for communication with data processingdevice 510 via a data bus 511. Read/write memory 550 is adapted forcommunication with data processing device 510 via a data bus 514. To thedata communications port 599 e.g. the links connected to the control units100 may be connected.

When data is received on data port 599 it is temporarily stored in secondmemory portion 540. When the received input data has been temporarilystored, data processing device 510 is set up to perform execution of code ina manner described above. The signals received on data port 599 can beused by apparatus 500 for detecting in a line of sight the direction of travel ofthe host vehicle so as to detect a preceding vehicle. The signals received ondata port 599 can be used by apparatus 500 for determining whether thepreceding vehicle is deviating from the detected line of sight, deviationcomprising the preceding vehicle disappearing from the detected line of sight.The signals received on data port 599 can be used by apparatus 500 fordetermining, if there is a deviation, the character of the deviation. The signalsreceived on data port 599 can be used by apparatus 500 for and controllingthe speed of the host vehicle based upon the thus determined character ofsaid deviation. The signals used by apparatus 500 for determining the 31 character of the deviation comprises determining whether the deviation islikely to result in the preceding vehicle disappearing and not reappearing inthe detected direction of travel of the host vehicle or whether the deviation islikely to result in the preceding vehicle reappearing in the detected directionof travel of the host vehicle. The character of the deviation comprises any of:preceding vehicle having entered a roundabout, the preceding vehicle havingentered an exit from the road along which the host vehicle is travelling, thepreceding vehicle having changed or is changing lane, the host vehiclehaving changed or is changing lane, the preceding vehicle having entered acurve, the preceding vehicle having entered a slope. The signals received ondata port 599 can be used by apparatus 500 for determining the lane of thepreceding vehicle and the lane of the host vehicle. The signals received ondata port 599 can be used by apparatus 500 for determining the configurationof the road along which the host vehicle is travelling based on a determinedcurrent position of the host vehicle and extracted map information of theextension of the road along which the vehicle is travelling so as to determinepossible characters of deviation of a preceding vehicle. The signals receivedon data port 599 can be used by apparatus 500 for establishing contact withthe preceding vehicle within a vehicle-to-vehicle communicationarrangement. The signals received on data port 599 can be used byapparatus 500 for receiving information from the preceding vehicle aboutintention to deviate from the detected direction of travel of the host vehicleresulting 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 500by means of data processing device 510 running the program stored inseparate memory 560 or read/write memory 550. When apparatus 500 runsthe program, parts of the methods described herein are executed.

The foregoing description of the preferred embodiments of the presentinvention has been provided for the purposes of illustration and description. lt 32 is not intended to be exhaustive or to limit the invention to the precise formsdisclosed. Obviously, many modifications and variations will be apparent topractitioners skilled in the art. The embodiments were chosen and describedin order to best explain the principles of the invention and its practicalapplications, thereby enabling others skilled in the art to understand theinvention for various embodiments and with the various modifications as are suited to the particular use contemplated.

Claims

33 CLAIIVIS

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) soas to detect a preceding vehicle (2); determining whether the precedingvehicle (2) is deviating from the detected line of sight (LS), deviationcomprising the preceding vehicle (2) disappearing from the detected line ofsight (LS), characterized by the steps of: - determining, if there is a deviation, the character of the deviation; and - controlling the speed of the host vehicle (1) based upon the thusdetermined character of said deviation.

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

3. A method according to claim 1 or 2, wherein the character of thedeviation comprises any of: preceding vehicle (2) having entered aroundabout (RA), the preceding vehicle (2) having entered an exit from theroad (R) along which the host vehicle (1) is travelling, the preceding vehicle(2) having changed or is changing lane, the host vehicle (1) having changedor 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 ofdetermining the lane of the preceding vehicle (2) and the lane of the hostvehicle (1).

5. A method according to any of claims 1-4, comprising the step ofdetermining the configuration of the road (R) along which the host vehicle (1) 34 is travelling based on a determined current position of the host vehicle andextracted map information of the extension of the road (R) along which thevehicle is travelling so as to determine possible characters of deviation of apreceding vehicle (2).

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

7. A system (l) for controlling the speed of a host vehicle (1) along a road(R) taking a preceding vehicle (2) into account, comprising means (110) fordetecting 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 determiningwhether the preceding vehicle (2) is deviating from the detected line of sight(LS), deviation comprising the preceding vehicle (2) disappearing from thedetected line of sight (LS), characterized by means (130) for determining, ifthere is a deviation, the character of the deviation; and means (140) forcontrolling the speed of the host vehicle (1) based upon the thus determinedcharacter of said deviation.

8. A system od according to claim 7, wherein the means (130) fordetermining the character of the deviation comprises means (132) fordetermining 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 thepreceding vehicle (2) reappearing in the detected direction of travel (T1) ofthe host vehicle (1).

9. A system according to claim 7 or 8, wherein the character of the deviationcomprises any of: preceding vehicle (2) having entered a roundabout (RA),the preceding vehicle (2) having entered an exit (L1e) from the road (R)along which the host vehicle (1) is travelling, the preceding vehicle (2) havingchanged or is changing lane, the host vehicle (1) having changed or ischanging lane, the preceding vehicle (2) having entered a curve, thepreceding vehicle (2) having entered a slope.

10. A system according to any of claims 7-9, comprising means (150) fordetermining the lane of the preceding vehicle (2) and means (160) fordetermining the lane of the host vehicle (1 ).

11. A system according to of claims 7-10, comprising means (170) fordetermining the configuration of the road (R) along which the host vehicle (1)is travelling based on a determined current position of the host vehicle andextracted map information of the extension of the road (R) along which thevehicle is travelling so as to determine possible characters of deviation of apreceding vehicle (2).

12. A system according to of claims 7-11, comprising means for establishing contact with the preceding vehicle (2) within a vehicle-to-vehiclecommunication arrangement (V2V); and means for receiving information fromthe preceding vehicle (2) about intention to deviate from the detecteddirection of travel (T1) of the host vehicle (1) resulting in disappearing andnot reappearing or disappearing and reappearing in the detected direction of travel (T1) of the host vehicle (1 ).

13. A vehicle (1) comprising a system (l) according to any of claims 7-12.

14. A computer program (P) for controlling the speed of a host vehicle (1),said computer program (P) comprising program code which, when run on anelectronic control unit (100) or another computer (500) connected to theelectronic control unit (100), causes the electronic control unit to perform thesteps according to claim 1-6. 36

15. A computer program product comprising a digital storage medium storing the computer program according to c|aim 14.