SE1450035A1 - Method and apparatus for providing decision support to a driver prior to overtaking - Google Patents

Abstract

Method and apparatus for providing decision support to a driver of his own vehicle (1) prior to the overtaking of a vehicle in front (5). The method comprises receiving a single speed vset indicating the desired speed of the own vehicle (1) and determining a speed Vf of the vehicle in front. Then the difference Av between vset and Vf is calculated and for at least one section S1 the much longer time Atl the section S1 takes for the own vehicle (1) is calculated as it runs in speed vf instead of in vset based on the difference Av. Then the time Atl is presented to the driver of the own vehicle (1).

Description

2 It is thus an aim to provide support for the driver to make decisions in the event of a overtaking situation based on minimizing fuel consumption but reaching the final destination on time.

SUMMARY OF THE INVENTION According to a first aspect, the object described above is achieved at least in part by a method for providing decision support to a driver of his own vehicle prior to overtaking a vehicle in front. The method comprises receiving a speed vsef indicating the desired speed of the own vehicle, and determining a speed vf of the vehicle in front. A difference Av between vsef and vf is determined, and it is calculated for at least one distance Sf how much longer the Atf distance Sf takes for one's own vehicle as it runs at the speed vf instead of in vsef based on the difference Av. The method also includes presenting the time Atf to the driver of the own vehicle.

According to a second aspect, the object described above is achieved at least in part by means of an apparatus for providing decision support to a driver of his own vehicle before a overtaking of a vehicle in front. The apparatus comprises a processor unit configured to receive speed data indicating a speed vsef indicating the desired speed of the own vehicle, and to determine a speed vf of the vehicle in front. The processor unit is also configured to calculate a difference Av between vsef and vf, and to calculate for at least one distance Sf how much longer Atf the distance Sf takes for its own vehicle as it runs at the speed vf instead of with vsef based on the difference Av. The processor unit is further configured to generate a first presentation signal of indicating the time Atf and send it to a presentation unit whereby the time Atf is presented to the driver through the presentation unit.

Through either of the aspects, the driver of his own vehicle is helped to make wise choices where the driver himself can balance the requirement for delivery precision and the desire to save fuel. This can lead to more people choosing not to re-drive vehicles in front with fuel savings and / or better traffic flow as a result. According to a third aspect, the purpose is achieved at least in part by a computer program P, comprising program code for causing an apparatus to perform the steps according to the method. According to a fourth aspect, the object is achieved at least in part by a computer program product comprising a program code stored on a computer-readable non-volatile medium for performing the method when said program code is run on an apparatus.

Preferred embodiments are described in the dependent claims and in the detailed description.

Brief Description of the Attached Figures The invention will be described below with reference to the accompanying figures, of which: Fig. 1 shows an example of an own vehicle with which the method can be applied and in which the apparatus can be integrated.

Fig. 2 shows an own vehicle and a vehicle in front which is driven along a road.

Fig. 3 shows the apparatus according to an embodiment of the invention.

Fig. 4 illustrates examples of average fuel savings for all vehicles in vehicle trains with different numbers of vehicles.

Fig. 5 illustrates what can be displayed on the presentation unit according to an embodiment in the own vehicle.

Fig. 6 shows a flow chart of the method according to an embodiment.

Detailed Description of Preferred Embodiments of the Invention Fig. 1 shows an example of a vehicle 1 in which an apparatus 2 for providing decision support to the driver of the vehicle 1 can be integrated. The vehicle is shown here in the form of a truck, but can instead be, for example, a car or any other vehicle. The vehicle 1 is provided with a presentation unit 3 which may comprise a monitor and / or a loudspeaker. The vehicle 1 may also be provided with a detector unit 4, which may be intended to determine a distance ddi? to a vehicle 5 in front of 10 15 20 25 30 4, and / or a speed difference vdi? between the vehicle 1 and the vehicle in front 5. The vehicle in front 5 means a vehicle which is located directly in front of the own vehicle 1. The detector unit 4 may for instance comprise a radar unit, a camera unit and / or a laser unit.

The vehicle 1 may further be provided with a cruise control 10, for example an adaptive cruise control, which the driver can set to maintain a certain desired speed vset for his own vehicle 1. The cruise control 10 is thus configured to ensure that the own vehicle 1 maintains a certain the time slot tset between the own vehicle 1 and the vehicle in front 5. The desired speed vset can also be called the seat speed of the vehicle. The cruise control 10 can then be configured to calculate which time slot it should hold to the vehicle in front 5 based on the speed of its own vehicle 1, and generate reference values for an engine system in the vehicle 1 that regulates the vehicle 1 based on the reference values so that the time slot between vehicles 1 , 5 maintained. The reference values can be, for example, speed reference values which indicate what speed the vehicle 1 must have to maintain the time slot, or energy reference values which indicate how much fuel is to be injected into the engine of the vehicle 1 in order to maintain the time slot. The vehicle 1 can also be provided with a navigation system 11, which based on the current position of the own vehicle 1 pego and final destination is configured to determine the total distance that the own vehicle 1 is to drive. By the total distance is meant the length of the distance between the current position of the own vehicle 1 and its final destination. The current position of the own vehicle 1 can be determined, for example, by a positioning unit 15 in the vehicle 1 which is configured to determine the position of the own vehicle 1. The positioning unit 15 may, for example, be configured to receive signals from a global positioning system such as GNSS (Global Navigation Satellite System) such as GPS (Global Positioning System), GLONASS, Galileo or Compass. Alternatively, the positioning unit 15 may be configured to receive signals from, for example, one or more detectors 4 in the vehicle 1 which measure relative distances to objects such as a road node, vehicles in the vicinity or the like with a known position. Based on the relative distances, the positioning unit 15 can then determine the position of the vehicle 1. A detector can also be configured to sense a signature in, for example, a road node, the signature representing a certain position. The positioning unit 15 can then be configured to determine its position by sensing the signature. The positioning unit 15 can instead be configured to determine the signal strength in one or more signals from several base stations and / or road nodes etc. with known position, and thereby determine the position of the vehicle 1 by triangulation. Of course, the above techniques can also be combined to ensure the position of the vehicle 1. The final destination of the vehicle can, for example, be specified by the driver or communicated via a haulier via, for example, a server. The navigation system 11 can then be configured to use map data to determine a route of the vehicle 1 from its current position to its final destination, and to determine the length of the distance between the vehicle's current position to its final destination. The navigation system 11 can also be configured to determine how long it will take for the vehicle 1 to travel the determined distance taking into account speed limitations etc. The navigation system 11 can base its calculation either on a predetermined speed of the vehicle, or by obtaining information about the desired speed of the vehicle from, for example, the cruise control 10.

The various units in the vehicle 1 can communicate internally with each other and the apparatus 2 through, for example, a bus, for example a CAN bus (Controller Area Network), which uses a message-based protocol. Examples of other communication protocols that can be used are TTP (Time-Triggered Protocol), Flexray and others. In this way, signals and data described herein can be exchanged between different units in the vehicle 1. For example, signals and data can instead be transmitted wirelessly between the different units and the device 2. According to one embodiment, the device 2 is a control unit, an ECU (Electronic Control Unit) . According to one embodiment, the apparatus 2 also comprises one or more of the units described herein.

The vehicle 1 may also be provided with a wireless communication unit 12, which is adapted to receive and / or send data to other vehicles and / or infrastructure and / or servers. Fig. 2 shows an example of an own vehicle 1 which is located directly behind a vehicle in front 5. Vehicles 1, 5 are both equipped to be able to communicate wirelessly, which is shown by an antenna 6 of each vehicle. . Vehicles 1, 5 may be configured to communicate directly with each other, also called "vehicle-to-vehicle" communication, via a roadside unit 7 or other central unit, which is then called "vehicle-to-infrastructure" communication, or via a server, which can be called “vehicle-to-server” communication.When the own vehicle 1 uses adaptive cruise control, the cruise control 10 ensures that a time slot tset is maintained between the vehicles 1, 5.

Fig. 3 illustrates how the device 2 receives data from the units described above, and the function of the device 2 will now be described in more detail.

The apparatus 2 comprises a processor unit 8 which is configured to receive speed data indicating a speed value which indicates the desired speed of the own vehicle 1. The speed vset can for example be obtained from the cruise control 10.

According to one embodiment, the processor unit 8 comprises a CPU (Central Processing Unit). The apparatus 2 also comprises a memory unit 9, which according to one embodiment comprises a non-volatile memory (NVM), for example a flash memory. The memory unit 9 comprises a computer program P with computer program instructions for causing the apparatus 2 to perform the steps which will be described in the following, when the computer program instructions are run on processor unit 8 in the apparatus 2. The memory unit 9 can be described as a form of computer program product. The computer program instructions are thus stored on a medium readable by a computer system. The computer program instructions may also be stored on a CD or the like.

The processor unit 8 is configured to determine a speed vf of the vehicle in front 5. This can be done in different ways. If the own and the front vehicle 1, 5 are equipped with equipment for wireless communication, the own vehicle 1 can be informed about the speed of the front vehicle 5 via wireless communication via the unit for wireless communication 12. Another way of determining the front vehicle 10 The speed unit can detect the speed difference vofff between the vehicles 1, 5 by means of the detector 4 in the own vehicle 1. The processor unit 8 can also be configured to receive data regarding the current speed of the own vehicle vego, which need not be the same as the desired speed veef. The data with the own vehicle vego speed can for example come from a speed sensor in the own vehicle 1. By subtracting the speed difference vofff from the own vehicle 1's own speed vego, then the speed vf of the vehicle in front 5 can be calculated. Another alternative is to simply wait until the speed of the own vehicle 1 has stabilized when the own vehicle 1 is placed behind the vehicle in front 5, whereby the vehicles 1, 5 can be assumed to have the same speed. This can be determined, for example, by detecting that the distance between the vehicles 1, 5 does not change. The speed of the own vehicle vego is then equal to the speed vf of the vehicle in front 5, and vego can be used as an indication of the speed vf of the vehicle in front 5.

The processor unit 8 is further configured to calculate a difference Av between veef and vf, and to calculate for at least one distance Sf how much longer Atf the distance Sf takes for the own vehicle 1 when it runs at the speed vf instead of with veef based on the difference Av . Generally, the time Atf is calculated using the equation (1): Ae = å (u "k" can vary from "1" to a desired number of "n" distances. The processor unit 8 is further configured to generate a first presentation signal af indicating the time Atf. and send it to the presentation unit 3, whereby the time Atf is presented to the driver through the presentation unit 3. In this way, the driver can see how much longer the journey will take for different distances, thus giving the driver a basis for deciding if he will still arrive. in time even if he remains behind the vehicle in front 5. According to one embodiment, the processor unit 8 is configured to receive data as the indicator time slot tset.The data can be obtained, for example, via the cruise control 10 in the own vehicle 1. The processor unit 8 is further configured to determine a reduction Ab in fuel consumption for the own vehicle 1 based on the time slot tset.The reduction Ab can be determined for example by using a predetermined table describing the relationship between fuel economy and time slot tset. For example, the table can be stored in the memory unit 9 so that the processor unit 8 can retrieve data from the table. An example of a diagram showing the relationship between fuel saving and the time slot tset is shown in Fig. 4.

The data in the diagram in Fig. 4 can thus be formed by the table instead. The diagram shows on a shaft the time slot tset in seconds. The second axis shows the average fuel saving Ab as a percentage (%) of the average fuel consumption that the vehicles in the vehicle train would have if they did not drive in a vehicle train, but drove individually, for all vehicles in a vehicle train. To illustrate the advantages of staying behind the vehicle in front 5, the average saving when the vehicle train is also included includes more vehicles than the vehicle in front 5. In front of the vehicle in front 5, there may be more vehicles included in the same vehicle train as the vehicle in front. The more vehicles are included, the greater the average savings for each vehicle in the vehicle train. Thus, according to one embodiment, the own vehicle 1 can choose to be included in a vehicle train together with at least the vehicle in front 5. In Fig. 4, curve A2 shows the average fuel saving Ab if the own vehicle 1 is expected to be the other vehicle in the vehicle train. The vehicle in front 5 is then the leader vehicle, and the vehicles 1, 5 create a vehicle train together. Curve A3 shows the average fuel saving Ab if own vehicle 1 is expected to be the third vehicle in the vehicle train, curve A4 shows the average fuel saving Ab if own vehicle 1 is expected to be the fourth vehicle in the vehicle train, and curve A5 shows the average fuel saving own vehicle 1 is expected to be the fifth vehicle in the vehicle train. The own vehicle 1 can receive information about the vehicle in front 5 being included in a vehicle train, and also how many vehicles are included in the vehicle train, via wireless communication with the vehicle in front 5 or with a central unit or a server. In this way, the apparatus 2 and the processor unit 8 can know what place in the vehicle queue the own vehicle 1 would have if it were part of a vehicle train in which the vehicle in front 5 is included, and retrieve correct data from the table about which fuel saving Ab can be achieved.

According to another embodiment, only data concerning curve A2 are used, and the own vehicle 1 is always assumed to be number two in the vehicle train. In this way, the own vehicle 1 does not need to receive any information about what place in the vehicle train it would have.

According to a further embodiment, the processor unit 8 is also configured to calculate what fuel saving the own vehicle 1 makes when it runs at the lower speed that the vehicle in front 5 has, compared to driving the same distance with the higher speed vset. How much fuel the own vehicle 1 consumes at different speeds is often predefined, and given a distance, the fuel consumption of the own vehicle 1 during the distance can be calculated.

The fuel savings made by driving at a lower speed can then be calculated by comparing the fuel consumption when the own vehicle 1 is driving at the speed vset with the fuel consumption when the own vehicle 1 is driving at the speed vf. A fuel saving for the own vehicle 1 can thus be determined based on the speed difference Av, which is vf-vset. This additional fuel saving can be added to the fuel savings obtained by driving in a vehicle train, and is included in Ab. The processor unit 8 is thus configured to determine a reduction Ab in fuel consumption for the own vehicle 1 based on both the time slot tset and the difference Av. The processor unit 8 is further configured to generate a second presentation signal (12 indicating the reduction Ab and send it to the presentation unit 3, the reduction Ab being presented to the driver through the presentation unit 3. In this way the driver can get information about how much fuel he saves by staying behind it. in front of the vehicle 5, instead of overtaking and continuing at the desired speed vset.

According to one embodiment, the processor unit 8 is configured to calculate for a plurality of distances Sk how much longer Atk the distance Sk takes for its own vehicle 1 as it runs at the speed vf instead of in vger based on the difference Av, and generates 10 15 20 25 30 10 a first presentation signal di indicating the times Atk and sending it to the presentation unit 3, the times Atk being presented to the driver through the presentation unit 3. The processor unit 8 then performs a plurality of calculations according to equation (1). The sections Sk can be, for example, 1 km, 10 km and 100 km.

The distances Sk are according to an embodiment predetermined and stored on the memory unit 9. "k" can thus vary from "1" to a desired number of distances. In the example above, n = 3.

According to one embodiment, the distance S1 is the total distance of the own vehicle 1 from the current position of the own vehicle 1 to its final destination. The total distance is according to one embodiment predetermined by another system, for example the described navigation system 11, and is provided to the apparatus 2 and the processor unit 8 from the navigation system 11. According to another embodiment, the apparatus 2 comprises an input unit 14 through which the driver can enter desired or desired stretches Sk.

Fig. 5 shows an example of a screen 13 on a presentation unit 3 (Fig. 3). The screen displays data from the first and second presentation signals on, 0: 2.

According to one embodiment, the distance or distances Sk are also presented to the driver through the presentation unit 3. An example of this is shown in Fig. 5, which at the top of the screen 13 shows the distances 1, 10 and 100 km. Below it is shown how much extra time Atk it takes to drive the different distances, compared to if the own vehicle 1 had driven at its desired speed vsek instead. At the bottom of the screen 13 it is shown what fuel saving Ab the own vehicle 1 makes if it remains behind the vehicle in front 5. Fig. 5 illustrates only one example of what the presentation may look like, and the order and / or location of the listed values. may be different from what is shown. For example, only the total distance S1 and the extra time At1 it takes to drive it can be displayed, as well as what percentage of fuel savings Ab can be achieved.

The processor unit 8 is then configured to determine the reduction Ab in fuel consumption for the total distance S1 of the own vehicle 1 from the current position of the own vehicle 1 to its final destination. Of course, only the extra time At1 it takes to drive the total distance and the total fuel saving Ab can be displayed on the presentation unit 3. The fuel saving can also be presented in liters, or liters per 1, 10, or 100 km and so on. According to one embodiment, the total fuel saving for the total distance S1 is shown in liters.

The fuel consumption of the own vehicle as it is not included in a vehicle train is then used as a comparison.

According to another embodiment, the processor unit 8 is configured to receive route data ßf originating from the vehicle in front 5 indicating which route the vehicle in front 5 is to run. The route data ßf can for instance be received via wireless communication from the vehicle in front 5. The processor unit 8 is further configured to receive route data ßego from the own vehicle 1 which indicates which route the own vehicle 1 is to drive. The route data ßego from the own vehicle 1 can for instance be obtained via the navigation system 11. The processor unit 8 is further configured to compare the route data ßego of the own vehicle with the route data ßf of the vehicle in front, and determine the distance S1 to indicate the length of the distance during which the own vehicle 1 and the vehicle in front 5 has the same route based on the comparison. Route data can, for example, indicate longitude and latitude positions. The processor unit 8 can then be configured to compare if the positions correspond to each other within a predefined radius range, for example 5, 10, 20, 50 or 100 m. If they correspond within the range, the vehicles 1, 5 are considered to have the same route. With the help of route data for both vehicles 1, 5, the driver knows how long his own vehicle 1 and the vehicle in front 5 share the route.

Fig. 6 shows a flow chart of a method for providing decision support to a driver of his own vehicle prior to overtaking the vehicle in front 5. The method will now be explained with reference to this figure. The method can be implemented as computer instructions in a computer program P. When the computer program is run on the processor unit 8, the various steps in the method are performed. The method comprises receiving a speed vsef indicating the desired speed (B1) of the own vehicle 1, and determining a speed vf of the vehicle in front 5 (B2). Then a difference Av is calculated between vsef and vf (B3), and for at least one distance Sf it is calculated how much longer the Atf distance Sf takes for one's own vehicle 1 as it runs at speed vf instead of in vsef based on the difference Av (B4) . Then the time Atf is presented to the driver of the own vehicle (B5). The calculation of the difference Atf can be performed with equation (1).

According to one embodiment, the own vehicle 1 is equipped with a cruise control 10, for example an adaptive cruise control, which is configured to keep a certain time slot tsef between the own vehicle 1 and the vehicle in front 5. The method may then comprise determining a reduction Ab in fuel consumption for the own vehicle 1 based on the time slot tsef and the difference Av, and the reduction Ab is presented to the driver of the own vehicle 1.

According to another embodiment, the method includes calculating for a number of sections Sk how much longer the Atk section Sk takes for the own vehicle 1 as it runs at the speed vf instead of in vsef based on the difference Av, and presenting the times Atk to the driver. According to another embodiment, the distance Sf is the total distance of the own vehicle 1 from the current position of the own vehicle 1 to its final destination. In this way, the total difference between the own vehicle's estimated arrival time when driving at speed vsef and the estimated arrival time when own vehicle 1 is driving at the speed of the vehicle in front vf can be determined, ie the total time difference Atf. A navigation system 11 in the own vehicle 1 may be configured to determine the total distance of the own vehicle 1. According to a further embodiment, the determination of the reduction Ab in fuel consumption comprises determining the reduction Ab in fuel consumption for the total distance from the current position of the own vehicle 1. to its final destination. The total time difference Atf and the reduction Ab in fuel consumption for the total distance from the own vehicle's current position to its final destination can then be presented to the driver. According to another embodiment, the own vehicle 1 and the front vehicle 5 are configured to communicate wirelessly, the method comprising receiving route data originating from the front vehicle 5 indicating which route the front vehicle 5 is to drive, and receiving route data from the own vehicle 1 which indicates which route the own vehicle 1 is to drive. The method then comprises comparing the route data of the own vehicle 1 with the route data of the vehicle in front, and determining the distance S1 to indicate the length of the distance during which the vehicle 1 and the vehicle in front 5 have the same route based on the comparison.

The present invention is not limited to the embodiments described above. Various alternatives, modifications and equivalents can be used.

Therefore, the above-mentioned embodiments do not limit the scope of the invention, which is defined by the appended claims.

Claims (16)

10 15 20 25 30 14 Patent claims A method for providing decision support to a driver of his own vehicle (1) prior to overtaking a vehicle in front (5), the method comprising - receiving a speed vsef indicating the desired speed of the own vehicle (1); - determining a speed vf on the vehicle in front (5); - calculate a difference Av between vsef and vf; - calculate for at least one distance Sf how much longer the Atf distance Sf takes for the own vehicle (1) as it runs at the speed vf instead of in vsef based on the difference Av; - present the time Atf to the driver of the own vehicle. The method according to claim 1, wherein the own vehicle (1) is equipped with a cruise control (10) which is configured to hold a certain time slot tsef between the own vehicle (1) and the vehicle in front (5), - determining a reduction Ab in fuel consumption for the own vehicle (1) based on the time slot tsef and the difference Av; - present the reduction Ab to the driver of the own vehicle (1). The method according to any one of the preceding claims, which comprises calculating for a plurality of sections Sk how much longer the Atk section Sk takes for one's own vehicle (1) as it runs at the speed vf instead of in vsef based on the difference Av, and presenting the times Atk for the driver. The method according to any one of the preceding claims, wherein the distance Sf is the total distance of the own vehicle (1) from the current position of the own vehicle (1) to its final destination. The method according to claims 2 and 4, wherein the determination of the reduction Ab in fuel consumption comprises determining the reduction Ab in fuel consumption for the total distance of the own vehicle (1) from the current position of the own vehicle (1) to its final destination. The method according to claim 5, wherein the own vehicle (1) is equipped with a navigation system (11) which, based on the current position and final destination of the own vehicle (1), is configured to determine the total distance of the own vehicle (1). The method according to any of the preceding claims, wherein the own vehicle (1) and the vehicle in front (5) are configured to communicate wirelessly, the method comprising - receiving route data originating from the vehicle in front (5) indicating which route the vehicle in front (5) must drive; -receive route data from the own vehicle (1) which indicates which route the own vehicle (1) is to drive; - comparing the route data of the own vehicle (1) with the route data of the vehicle in front (5); determine the distance S1 to indicate the length of the distance during which the own vehicle (1) and the vehicle in front (5) have the same route based on the comparison. Apparatus (2) for providing decision support to a driver of his own vehicle (1) before overtaking a vehicle in front (5), the apparatus (2) comprising a processor unit (8) configured to - receive speed data indicating a speed vsef indicating the desired speed of the own vehicle (1); - determining a speed vf on the vehicle in front (5); - calculate a difference Av between vsef and vf; - calculate for at least one distance S1 how much longer At1 the distance S1 takes for one's own vehicle (1) when it is driving at the speed vf instead of with vse1 based on the difference Av; and generating a first presentation signal 0: 1 indicating the time At1 and transmitting it to a presentation unit (3), the time At1 being presented to the driver through the presentation unit (3). The apparatus (2) according to claim 8, wherein the own vehicle (1) is equipped with a cruise control (10) which is configured to hold a certain time slot between the own vehicle (1) and the vehicle in front (5), wherein the processor unit (8) is configured to - receive data indicating the time slot tset; - determine a reduction Ab in fuel consumption for the own vehicle based on the time slot tset and the difference Av; - generating a second presentation signal (12 indicating the reduction Ab and sending it to the presentation unit (3), the reduction Ab being presented to the driver through the presentation unit (3). The apparatus (2) according to any one of claims 8 or 9, wherein the processor unit (8) is configured to calculate for a plurality of distances Sk how much longer Atk the distance Sk takes for the own vehicle (1) when it runs at the speed vf instead for i vset based on the difference Av, and generate a first presentation signal ou which indicates the times Atk and send it to the presentation unit (3) whereby the times Atk are presented to the driver through the presentation unit (3). The apparatus (2) according to any one of claims 8 to 10, wherein the distance S1 is the total distance of the own vehicle (1) from the current position of the own vehicle (1) to its final destination. The apparatus (2) according to claims 9 and 11, wherein the processor unit (8) is configured to determine the reduction Ab in fuel consumption for the total distance of the own vehicle (1) from the current position of the own vehicle (1) to its final destination. 10 15 20 25 17 The apparatus (2) according to claim 12, wherein the own vehicle (1) is equipped with a navigation system (11) which, based on the current position and final destination of the own vehicle (1), is configured to determine the total distance of the own vehicle ( 1). The apparatus (2) according to any one of claims 8 to 13, wherein the own vehicle (1) and the vehicle in front (5) are configured to communicate wirelessly, the processor unit (8) being configured to - receive route data ßf originating from the vehicle in front (5) indicating which route the vehicle in front (5) is to drive; -receive route data ßego from the own vehicle (1) indicating which route the own vehicle (1) is to drive; -compare the route data ßego of the own vehicle with the route data ßf of the vehicle in front; determine the distance S1 to indicate the length of the distance during which the own vehicle (1) and the vehicle in front (5) have the same route based on the comparison. Computer program, P, comprising program code for causing an apparatus (2) to perform the steps according to the method according to any one of claims 1 to 7. A computer program product comprising a program code stored on a computer readable non-volatile medium for performing the method steps according to any one of claims 1 to 7, when said program code is executed on an apparatus (2).