METHOD FOR ADJUSTING THE SPEED OF A VEHICLE

Abstract

A method for adjusting the speed of a vehicle (EGO) moving with an initial speed to a target speed, including: determining a control profile comprising at least one control profile part, in which the control profile includes at least one control parameter for the vehicle (EGO) and allowing the vehicle (EGO) to change its speed from the initial speed to the target speed, and adjusting the speed of the vehicle (EGO) according to the control profile. A further method is disclosed for leading a vehicle (EGO) that is moving on a lane into a target position with respect to at least one other vehicle, in which the method is used to adjust the speed of the vehicle (EGO) to reach the target position. Also described are a related device, a system, a vehicle, a computer program product and a storage medium.

Claims

1-15. (canceled)

16. A method for adjusting the speed of an EGO vehicle moving with an initial speed to a target speed, the method comprising: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle.

17. The method of claim 16, wherein one control profile part includes an exclusive control parameter causing an acceleration or a deceleration.

18. The method of claim 16, wherein the control profile includes a switching point separating two control profile parts of the control profile from each other, and/or wherein the control profile includes an end point defining the end of the control profile when reached the speed of the EGO vehicle is equal to the target speed.

19. The method of claim 16, wherein the amount of the average acceleration and/or deceleration caused by two different control profile parts is equal.

20. The method of claim 16, wherein at least one of the control profile parts causes a linear adjusting of the speed.

21. The method of claim 16, wherein the control profile is based on time and/or speed of the EGO vehicle and/or distance of the EGO vehicle.

22. The method of claim 16, wherein the control parameter includes a target value, and/or a target speed value or a target speed profile, and/or a target force or target torque value or a target force or target torque profile, and/or a target engine load value or a target engine load profile, and/or a target brake demand value or a target brake demand profile.

23. A method for leading an EGO vehicle that is moving on a lane into a target position with respect to at least one other vehicle, the method comprising: determining a current position of the EGO vehicle with respect to the at least one other vehicle; determining the target position with respect to the at least one other vehicle; and executing a process, to reach the target position, when the current position is not equal to the target position, for adjusting the speed of the EGO vehicle moving with an initial speed to a target speed, by performing the following: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle.

24. The method of claim 23, wherein the control profile is determined so that the speed of the EGO vehicle includes the target speed when reaching the target position, and/or wherein the at least one other vehicle is moving in front of the EGO vehicle or behind the EGO vehicle or on an adjacent lane.

25. The method of claim 23, further comprising: determining the target speed from an external source, which is from a traffic sign and/or from a digital source and/or from the speed of at least one other vehicle.

26. A device for adjusting a speed of an EGO vehicle, comprising: a control means for adjusting the speed of the EGO vehicle moving with an initial speed to a target speed, by performing the following: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle; and an interface to supply the control profile to the EGO vehicle, and/or to receive data from the EGO vehicle.

27. A system, comprising: a device for adjusting a speed of an EGO vehicle, including a control means for adjusting the speed of the EGO vehicle moving with an initial speed to a target speed, by performing the following: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle; an interface to supply the control profile to the EGO vehicle, and/or to receive data from the EGO vehicle; and at least one detection means for detecting information from the surrounding of the EGO vehicle.

28. The system of claim 27, wherein the at least one detection means includes at least one of a camera, a radar sensor, a GPS-receiver and/or a radio receiver, and wherein the system is configured to determine the target speed and/or the target position from the information of the detection means.

29. An EGO vehicle, comprising: a device for adjusting a speed of an EGO vehicle, including: a control means for adjusting the speed of the EGO vehicle moving with an initial speed to a target speed, by performing the following: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle; and an interface to supply the control profile to the EGO vehicle, and/or to receive data from the EGO vehicle.

30. A non-transitory computer readable medium having a computer program, which is executable by a processor, comprising: a program code arrangement having program code for adjusting the speed of an EGO vehicle moving with an initial speed to a target speed, by performing the following: determining a control profile comprising at least one control profile part, wherein the control profile includes at least one control parameter for the EGO vehicle and allowing the EGO vehicle to change its speed from the initial speed to the target speed; and adjusting the speed of the EGO vehicle according to the control profile or supplying the control profile to a speed control system of the vehicle to adjust the speed of the EGO vehicle.

31. The computer readable medium of claim 30, wherein one control profile part includes an exclusive control parameter causing an acceleration or a deceleration.

32. The method of claim 16, wherein one control profile part includes an exclusive control parameter causing an acceleration or a deceleration, and wherein, when the control profile consists of two control profile parts, one of the two control profile parts includes an exclusive control parameter causing an acceleration and the other of the two control profile parts causing a deceleration.

33. The method of claim 16, wherein the control profile includes a switching point separating two control profile parts of the control profile from each other, the switching point dividing the control profile into two control profile parts, and/or wherein the control profile includes an end point defining the end of the control profile when reached the speed of the EGO vehicle is equal to the target speed.

34. The method of claim 16, wherein at least one of the control profile parts causes a linear adjusting of the speed, and wherein the control profile causes exclusively a linear adjusting of the speed.

35. The method of claim 16, wherein the control parameter includes a target value, which is a target acceleration value or a target acceleration profile, and/or a target speed value or a target speed profile, and/or a target force or target torque value or a target force or target torque profile, and/or a target engine load value or a target engine load profile, and/or a target brake demand value or a target brake demand profile.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0046] FIG. 1 shows a traffic situation for the executing of the method according to the invention.

[0047] FIG. 2 shows another traffic situation for the executing of the method according to the invention.

[0048] FIG. 3 shows the execution of the method according to the invention using speed and distance profiles.

[0049] FIG. 4 shows special use cases of the invention.

DETAILED DESCRIPTION

[0050] FIG. 1 shows a traffic situation seen from above for the executing of the method according to the invention.

[0051] Two lanes L.sub.1, L.sub.2 are shown in the drawing, extending from the left to the right and being parallel and adjacent to each other. In the drawing traffic is moving on both lanes L.sub.1, L.sub.2 from the left to the right. A vehicle EGO moves on the lane L.sub.1 with a speed v.sub.ego, 0 from the left to the right. The vehicle EGO is configured to adjust its speed by a speed control system according to a control parameter that can be supplied to the speed control system of the vehicle EGO. On lane L.sub.2, four vehicles 1, 2, 3, 4 are moving with a speed v.sub.L. Between the vehicles 1, 2, 3, 4 there are gaps d.sub.L, 12, d.sub.L, 23, d.sub.L, 34. In the situation shown in the drawing the vehicle EGO has a current or initial position d.sub.0, ego with reference to vehicle 2. The vehicles 1, 2, 3, 4 can for example form a platoon.

[0052] The lane L.sub.1 where the vehicle EGO is moving, is limited in its extension to the right. For example, lane L.sub.1 is a merging lane. Therefore, the vehicle EGO needs to change to lane L.sub.2 by a lane change maneuver. However, before the vehicle EGO can execute the lane change maneuver, it has to adjust its position and its speed with reference to the vehicles 1, 2, 3, 4 moving already on lane L.sub.2, to reach an initial state the vehicle EGO must have for the lane change maneuver.

[0053] Above the lanes L.sub.1, L.sub.2, a time axis t and an axis indicating the distance s(t) are shown, wherein the axis indicating the distance s(t) corresponds to the distance the vehicle EGO moves from left to right.

[0054] In this situation, it is an object to get the vehicle EGO into a position on lane L.sub.1 with respect to at least one of the vehicles 1, 2, 3, 4 that the vehicle EGO can start a lane change maneuver in order to change from lane L.sub.1 to L.sub.2. Further, the speed of the vehicle EGO has to be adjusted in such way that a lane change maneuver can be started. Therefore, the speed of the vehicle EGO must not be too slow or too fast. For example, the speed of the vehicle EGO should be equal to the speed v.sub.L of the vehicles 1, 2, 3, 4 or at least within the same scale. Further, the ending of the lane L.sub.1 has to be considered by the method.

[0055] According to the invention, a control profile is determined comprising at least one control parameter allowing adjusting the speed of the vehicle EGO to a target speed. The target speed can be determined as stated above, from the speed v.sub.L of the vehicles 1, 2, 3, 4. The control parameter can comprise a target profile or value, that is supplied to the speed control system of the vehicle EGO. For example, the control parameter comprises a target value as described above.

[0056] In the drawing, a switching point T.sub.1 is shown, which is determined as a part of the control profile. In this embodiment of the invention the switching point is a point of time, whereby two control profile parts are separated.

[0057] Further, an end point T.sub.m is shown, which is determined as a part of the control profile. In this embodiment of the invention the end point is a point of time, whereby the ending of the control profile and its duration is defined.

[0058] During the time period from 0 to T.sub.1, adjusting the speed of the vehicle EGO is executed according to a first control profile part and during the time period from T.sub.1 to T.sub.m, adjusting the speed of the vehicle EGO is executed according to a second control profile part. For example, both control profile parts can be configured to cause exclusively acceleration of the vehicle EGO during the executing one of both control profile parts, wherein during executing of the other control profile part exclusively deceleration of the vehicle EGO is caused.

[0059] By the determination of the end point T.sub.m the time is set for adjusting the distance d.sub.0, ego to the distance needed to join the platoon and for adjusting the speed of the vehicle EGO to a corresponding speed.

[0060] FIG. 2 shows another traffic situation seen from above for the executing of the method according to the invention.

[0061] A vehicle EGO is shown which corresponds to the vehicle EGO of FIG. 1. The vehicle EGO is moving with its speed v.sub.ego, 0 from the left to the right on a lane L.sub.3 which is extending from the left to the right.

[0062] The vehicle EGO is approaching to several vehicles 1, 2, 3, 4 moving in front of the vehicle EGO, wherein the vehicles 1, 2, 3, 4 are moving with a speed v.sub.L on the same lane L.sub.3. The vehicles 1, 2, 3, 4 can, for example, act as a platoon as shown in FIG. 1. In the situation shown on the drawing, the vehicle EGO is in an initial position d.sub.0, ego with reference to the vehicle 1.

[0063] Above the lane L.sub.3, a time axis t and an axis indicating the distance s(t) are shown, wherein the axis indicating the distance s(t) corresponds to the distance the vehicle EGO moves from left to right.

[0064] In this situation, it can be an object to get the vehicle EGO into a position on lane L.sub.3 with respect to at least one of the vehicles 1, 2, 3, 4, in particular to vehicle 1, wherein the vehicle EGO can join the platoon of the vehicles 1, 2, 3, 4. Further, the speed of the vehicle EGO has to be adjusted in such way, that no safety critical situation appears on the one hand and that on the other hand the vehicle EGO can reduce the distance to the vehicle 1 indeed. Therefore, the speed of the vehicle EGO in the target position behind vehicle 1 must not be too slow or too fast. For example, the speed of the vehicle EGO should be equal to the speed v.sub.L of the vehicles 1, 2, 3, 4 or at least within the same scale.

[0065] According to the invention, a control profile is determined comprising at least one control parameter allowing adjusting the speed of the vehicle EGO to a target speed. The target speed can be determined as stated above, from the speed v.sub.L of the vehicles 1, 2, 3, 4. The control parameter can comprise a target profile or value, that is supplied to the speed control system of the vehicle EGO. For example, the control parameter comprises a target value as described above.

[0066] In the drawing, a switching point T.sub.1 is shown, which is determined as a part of the control profile. In this embodiment of the invention the switching point T.sub.1 is a point of time, whereby two control profile parts are separated.

[0067] Further, an end point T.sub.m is shown, which is determined as a part of the control profile. In this embodiment of the invention the end point T.sub.m is a point of time, whereby the ending of the control profile and its duration is defined.

[0068] During the time period from 0 to T.sub.1, adjusting the speed of the vehicle EGO is executed according to a first control profile part and during the time period from T.sub.1 to T.sub.m, adjusting the speed of the vehicle EGO is executed according to a second control profile part. For example, both control profile parts can be configured to cause exclusively acceleration of the vehicle EGO during the executing one of both control profile parts, wherein during executing of the other control profile part exclusively deceleration of the vehicle EGO is caused.

[0069] By the determination of the end point T.sub.m the time is set for adjusting the distance d.sub.0, ego to the distance needed to join the platoon and for adjusting the speed of the vehicle EGO to a corresponding speed.

[0070] FIG. 3 shows the execution of the method according to the invention using speed and distance profiles.

[0071] In the drawing shown above, a time based control parameter as part of a control profile is shown comprising a target speed profile of the vehicle EGO as shown in FIG. 1 or FIG. 2. If this control profile, in particular this control parameter, is supplied to the speed control system of the vehicle EGO as a target value, the vehicle EGO will adjust its speed according to the control profile, which causes acceleration or deceleration of the vehicle EGO.

[0072] The target speed profile begins with an initial speed v.sub.ego,0 the vehicle is moving at time 0. The target speed profile is comprising an end point T.sub.m wherein the target speed v.sub.ego, target is reached. Between time 0 and the end point T.sub.m, a switching point T.sub.1 is shown. The switching point T.sub.1 divides the target speed profile into to control profile parts. The first control profile part extends from time 0 to the switching point T.sub.1 wherein the second profile part extends from the switching point T.sub.1 to the end point T.sub.m.

[0073] The first control profile part causes the vehicle EGO exclusively to increase its speed wherein at the switching point T1 the speed can be calculated as

v.sub.ego(T.sub.1)=v.sub.ego, 0+a.sub.ego×T.sub.1,

wherein a.sub.ego is the average acceleration from time 0 to the switching point T.sub.1. It has to be noted, that the value of v.sub.ego(T.sub.1) is bigger than the target speed v.sub.ego, target. This is the general case when the control profile consists of two parts and when the control profile starts with a control profile part causing the acceleration of the vehicle EGO.

[0074] The second control profile part causes the vehicle EGO exclusively to decrease its speed to reach v.sub.ego, target at the end point T.sub.m.

[0075] In the case shown in the drawing, the amount of the average acceleration from time 0 to T.sub.1 and the amount of the average acceleration from time T.sub.1 to T.sub.m are equal. In general, they can differ from each other. Further, the speed profile shown in the drawing comprises two control profile parts with a linear character. In general, profiles that are more complex are possible as well.

[0076] In the lower part of FIG. 3 time based plots of the distance s(t) the vehicle EGO and other vehicles 1, 2, 3, 4 are shown. For simplification, it is assumed, that the vehicles 1, 2, 3, 4 are moving with the same constant speed. Therefore, the plots of their distances s.sub.1(t), s.sub.2(t), s.sub.3(t), s.sub.4(t) are linear and oriented in parallel to each other. Further, the distances d.sub.L, 12, d.sub.L, 23, d.sub.L, 34 between the vehicles 1, 2, 3, 4 are constant.

[0077] Further, in the drawing three trajectories s.sub.ego, 1(t), s.sub.ego, 2(t), s.sub.ego, 3(t) are shown by dotted lines representing three possible ways the vehicle EGO can take to adjust its speed and its position with reference to the vehicles 1, 2, 3, 4. At the time 0 the vehicle EGO is moving between the vehicles 2 and 3, wherein there is an initial distance d.sub.ego, 0 between the vehicle EGO and the vehicle 2.

[0078] In this situation, for example it is the object bringing the vehicle EGO into a position allowing the start of a lane change into a gap between two of the vehicles 1, 2, 3, 4. This situation is similar to the situation shown in FIG. 1.

[0079] If the vehicle EGO shall move into the gap between vehicle 3 and 4, it has to adjust its position with reference to the other vehicles 1, 2, 3, 4 according to s.sub.ego, 1(t) corresponding to the control profile shown in the drawing above. Therefore, the vehicle EGO has to accelerate to overtake vehicle 3 and to establish a safety distance to this vehicle 3. The acceleration stops by reaching the switching point T.sub.1 wherein the vehicle EGO starts to reduce its speed to reach the target position between the vehicles 3 and 4 with the target speed v.sub.ego, target. The time points T.sub.1 and T.sub.m and the amount of the acceleration and deceleration are determined by the determining of the profile shown above.

[0080] If the vehicle EGO shall change into another gap for example between the vehicles 1 and 2 or 2 and 3, another control profile is determined by the method according to the invention, causing the vehicle EGO to follow the trajectories according to the distances s.sub.ego, 2(t) or s.sub.ego, 3(t). The control profiles causing these trajectories differ from the control profile causing the trajectory according to s.sub.ego, 1(t).

[0081] FIG. 4 shows special use cases of the invention. In these cases the control profile comprises only one control profile part. Such control profiles are for example determined when the switching point T.sub.1 is set equal to the end point T.sub.m.

[0082] The upper drawing shows the case when the initial speed v.sub.ego, 0 shall be adjusted to a target speed v.sub.ego, target, wherein the initial speed v.sub.ego, 0 is smaller than the target speed v.sub.ego, target. The lower drawing shows the other case, wherein the initial speed v.sub.ego, 0 is higher than the target speed v.sub.ego, target. In both cases only one control profile part can be identified wherein the corresponding control parameter only increases or decreases with an average acceleration or deceleration a.sub.ego. In the case shown in the drawing, the acceleration or deceleration a.sub.ego is constant during the only control profile part. In these special cases the speed at the switching point T.sub.1 or end point T.sub.m can be calculated as follows:

v.sub.ego(T.sub.1)=v.sub.ego,0+a.sub.ego×T.sub.1=v.sub.ego,target

Embodiment of the Invention

[0083] In the following, a particular embodiment of the invention is described based on mathematical formulas. This is a general and simplified use case of the invention for determination of a time based control profile comprising two control profile parts, wherein no constraint are considered. The embodiment shows the determination of a control profile, in particular the determination of the switching point T.sub.1 and the end point T.sub.m for the situation shown in FIG. 1. For simplification, it is assumed that the vehicles 1, 2, 3, 4 are all moving with the same speed v.sub.L. Further, the distances d.sub.L, 12, d.sub.L, 23, d.sub.L, 34 are all identical and therefore written as d.sub.L in the following. In addition it is assumed, that the amount of the acceleration and deceleration a.sub.ego the vehicle EGO uses for adjusting its speed v.sub.ego is equal.

[0084] Therefore, the distance s.sub.L(t) driven by one of the vehicles 1, 2, 3, 4 can be written as follows:

s.sub.L(t)=−d.sub.ego,0+v.sub.L×t

The speed v.sub.ego(T.sub.m) of the vehicle EGO at the end point T.sub.m can be calculated as follows:

v.sub.ego(T.sub.m)=v.sub.ego,0+a.sub.ego×T.sub.1−a.sub.ego×(T.sub.m−T.sub.1)  (1)

Further, the distance s.sub.ego(T.sub.m) driven by the vehicle EGO at the end point T.sub.m can be calculated as follows:

[00001]$\begin{array}{cc}{s}_{\mathrm{ego}}\left(T_m\right)=v_{\mathrm{ego},0}\times T_m+\frac{1}{2}{a}_{\mathrm{ego}}\times {T_1}^2-a_{\mathrm{ego}}\times T_1\times \left(T_m-T_1\right)-\frac{1}{2}\times {a_{\mathrm{ego}}\left(T_m-T_1\right)}^2& \left(2\right)\end{array}$

For the preparation of a lane change, the vehicle EGO shall have the same speed as the vehicles 1, 2, 3, 4 moving on the adjacent lane L.sub.2. Therefore, at the end point T.sub.m, v.sub.ego(T.sub.m) shall be equal to v.sub.L

v.sub.ego(T.sub.m)=v.sub.L  (3)

and the distance of the vehicle EGO at the end point T.sub.m shall be:

[00002]$\begin{array}{cc}{s}_{\mathrm{ego}}\left(T_m\right)=v_L\times T_m+\frac{d_L}{2}-d_{\mathrm{ego},0}+N\times d_L& \left(4\right)\end{array}$

Wherein N indicates the number of gaps the vehicle EGO has to pass to reach the gap it will enter.

[0085] Since the amount of the acceleration and deceleration a.sub.ego of the vehicle EGO is assumed to be equal, at the switching point T.sub.1, the following equation can be formulated:

[00003]$\begin{array}{cc}{a}_{\mathrm{ego}}=\frac{v_{\mathrm{ego}}\left(T_1\right)-v_{\mathrm{ego},0}}{T_1}=\frac{v_{\mathrm{ego}}\left(T_1\right)-v_{\mathrm{ego},0}}{T_m-T_1}& \left(5\right)\end{array}$$\mathrm{With}{v}_{\mathrm{ego}}\left(T_1\right)=v_{\mathrm{ego},0}+a_{\mathrm{ego}}\times T_1$

From the equations above, the following expressions for T.sub.1 can be formed:

[00004]$\begin{array}{cc}{T}_1=\frac{T_m}{2}+\frac{1}{2}\frac{v_L-v_{\mathrm{ego},0}}{a_{\mathrm{ego}}}& \left(6\right)\end{array}$$\begin{array}{cc}{T}_1=T_m-\sqrt{\frac{{T_m}^2}{2}-T_m\frac{v_L-v_{\mathrm{ego},0}}{a_{\mathrm{ego}}}+\frac{\frac{d_L}{2}-d_{\mathrm{ego},0}}{a_{\mathrm{ego}}}}& \left(7\right)\end{array}$

[0086] With the following expressions

[00005]$\begin{array}{cc}{T}_v\left(a_{\mathrm{ego}}\right)=\frac{v_L-v_{\mathrm{ego},0}}{a_{\mathrm{ego}}}& \left(8\right)\end{array}$

describing the time which it takes to reach v.sub.L from v.sub.ego, 0 when using the acceleration a.sub.ego, and

[00006]$\begin{array}{cc}{T_d}^2\left(a_{\mathrm{ego}}\right)=2\frac{\frac{d_L}{2}-d_{\mathrm{ego},0}+N\times d_L}{a_{\mathrm{ego}}}& \left(9\right)\end{array}$

describing the time which it takes to change the distance offset from d.sub.0 to d.sub.L/2 with the acceleration a.sub.ego, the following expressions for T.sub.m and T.sub.1 can be formed:

[00007]$\begin{array}{cc}{T}_m\left(a_{\mathrm{ego}}\right)=T_v\left(a_{\mathrm{ego}}\right)\left(1\pm \sqrt{2}\sqrt{1-{\left(\frac{T_d\left(a_{\mathrm{ego}}\right)}{T_v\left(a_{\mathrm{ego}}\right)}\right)}^2}\right)& \left(10\right)\end{array}$$\begin{array}{cc}{T}_1\left(a_{\mathrm{ego}}\right)=T_v\left(a_{\mathrm{ego}}\right)\left(1\pm \frac{1}{\sqrt{2}}\sqrt{1-{\left(\frac{T_d\left(a_{\mathrm{ego}}\right)}{T_v\left(a_{\mathrm{ego}}\right)}\right)}^2}\right)& \left(11\right)\end{array}$

[0087] This is the general relation between the control parameters T.sub.1, T.sub.m and a.sub.ego based on the initial parameters v.sub.ego, 0, v.sub.L, d.sub.ego, 0, d.sub.L. That means, that only from these initial parameters, a control profile can be determined.

THE LIST OF REFERENCE SIGNS IS AS FOLLOWS

[0088] 1 vehicle [0089] 2 vehicle [0090] 3 vehicle [0091] 4 vehicle [0092] a.sub.ego acceleration/deceleration of the vehicle EGO [0093] d.sub.L distance between vehicles [0094] d.sub.L, i distance between vehicles [0095] EGO vehicle [0096] L.sub.i lane [0097] s.sub.i distance [0098] S10 method step [0099] S12 method step [0100] S13 method step [0101] S14 method step [0102] S16 method step [0103] T.sub.1 switching point [0104] T.sub.m end point [0105] v.sub.ego speed of the vehicle EGO [0106] v.sub.ego, 0 initial speed of the vehicle EGO [0107] v.sub.ego, target target speed of the vehicle EGO [0108] v.sub.L speed of the vehicles 1, 2, 3, 4