GB2408247A

GB2408247A - Device for estimating the distance of an object in front of a vehicle

Info

Publication number: GB2408247A
Application number: GB0424906A
Authority: GB
Inventors: Allan Boyd; Helmut Fischer
Original assignee: Immobiliengesellschaft Helmut Fischer GmbH and Co KG
Current assignee: Immobiliengesellschaft Helmut Fischer GmbH and Co KG
Priority date: 2003-11-19
Filing date: 2004-11-11
Publication date: 2005-05-25
Anticipated expiration: 2024-11-11
Also published as: GB0424906D0; GB2408247B; DE10354154A1

Abstract

A device for estimating the distance of an object in front of a vehicle, the device comprising a body 12 having at least one mark 14, relating to the vehicle's speed, displayed in the field of vision of a person within the vehicle allowing said person to estimate said distance. The mark 14 may be displaced or varied in size as a result of varying the vehicle's speed, or alternatively more than one mark 14 may be provided, each mark 14 corresponding to a different vehicle speed. The body may be a transparent film attached to a windscreen or a sun visor of the vehicle, or alternatively it may be attached to an instrument panel of the vehicle. The body 12 may comprise a sliding section (21, fig 3) so as to allow adjustment for different distances from said person's eyes.

Description

Device and method for estimating a distance from a motor vehicle

travelling in front or an obstacle The invention relates to a device and a method for estimating a distance from a motor vehicle travelling in front or an obstacle, having a body which has at least one mark for estimating the distance,?;S a function of the vehicle's own velocity.

One of the most frequent causes of accidents and in particular of multiple pile-ups is vehicles travelling too close to one another. Although there are guideline values for the distance as a function of the velocity, such as a simple formula according to which the distance to be kept in metres should correspond to half the speedometer velocity, but this distance is frequently estimated incorrectly. Usually, the distance is underestimated, which results in vehicles travelling too close to one another. As a result of the fact that the distance which is maintained is usually too short, the distance measurements which are carried out result in a penalty which entail different consequences depending on the country.

Electronic distance measurement systems which have already been installed in vehicles and which are based on the radar principle or on ultrasonic sound measurement and which trigger visual and/or audible signals when the velocity-dependent distance is too short, already exist. Some perfected devices of this l - 2 type additionally usually act on the electronic accelerator pedal and/or the electronic brake, by which means a correct velocity-dependent safety distance from the vehicle travelling in front is set. However, practical experience with such equipment has shown that incorrect measurements often occur due to bad weather and these measurements nevertheless require the driver's attention. Electronic methods are also unavoidably susceptible to incorrect displays which cannot be assigned. Such devices are very expensive and require immediate installation in a new vehicle.

A main disadvantage in traffic is that the ability to estimate distance varies between individuals. Very different distance-estimating capabilities, which are above all specific to a particular person, are found.

The invention is therefore based on the object of easily enabling a person in a vehicle to estimate with relative precision the distance from the person in front or the motor vehicle travailing in front or from an obstacle.

This object is achieved according to the invention by means of a device according to Claim 1 and a method according to Claim 28. Further advantageous refinements of the invention are specified in the further dependent claims.

The device according to the invention for estimating a distance from a vehicle travelling in front or an obstacle, having a body which comprises at least one mark for estimating the distance as a function of the vehicle's own velocity, the at least one mark being

arranged or displayed in the field of vision of a

person, has the advantage that the person can estimate very quickly and easily whether the distance due to his own velocity is too large, too short or is maintained.

The at least one rna.:k which is displayed, for example, - 3 - on the windscreen or positioned in the field of vision of the person makes it possible for a rapid evaluation to be carried out, which is independent of the weather,

without adversely affecting the overall field of

5. vision. The person relates themarks to the external dimensions of the motor vehicle travelli.ng in front and can thus discern correctly whether the distance from the motor vehicle travelling in front is too short. The marks are configured in such a way that they correspond to the general guidelines for maintaining the vel.ocity- dependent distance. The above applies both to the driver of a vehicle and to the front seat passenger who can estimate the distance for himself or can support the driver in his estimation of the distance.

The device according to the invention is intended also to achieve the goal of providing the driver or front seat passenger with an increased sense of safety by virtue of the fact that the driver's own evaluation is checked by a simple estimation of the distance from the person in front. This device its not restricted to use in passenger cars but can also be used for all watercraft, land vehicles and aircraft. The following explanations apply to the example of a driver, but are not restricted thereto.

According to one advantageous refinement of the invention there is provision for a plurality of marks to be provided on the body and for the velocity to be displayed between the marks or in a way which is assigned to the marks. As a result, the person can directly estimate, as a function of the velocity at which he is actually travelli.ng, whether the distance from the vehicle travelling in front is satisfactory by reading the speedometer and subsequently assigning the mark. The mark can advantageously also be implemented by the specified velocity itself According to a further advantageous refinement of the - 4 invention there is provision that/ when a plurality of marks are present on the body, said marks are arranged along a common axis which corresponds to the viewing direction of the driver. As a result, the driver can carry out a Satisfactory estimation at different velocities while maintaining his viewing direction. At the same time, this axis can be used to orient the device with respect to the customary viewing direction of the driver in a sitting position in a motor vehicle, as a result of which the marks are oriented satisfactorily with respect to the field of vision of the driver.

According to a further advantageous refinement of the invention there is provision for the marks to be arranged on the body one behind the other along the axis in such a way that the mark for a high velocity is arranged in the lower region of the body, and the mark for a low velocity is arranged in an upper region of the body. As a result a fatigue-free arrangement is provided in which the driver always has the vehicle travelling in front of him in his field of vision. At the same time, a sufficient overview of the further events on the road can be maintained.

According to a further advantageous refinement of the invention there is provision that the at least one mark is formed by fluorescent, phosphorescent and/or electroluminescent substances. This permits the marks to be displayed simply on the windscreen. Furthermore, the device can also be used to estimate a distance from a vehicle travellir, in front when driving at night without an additional energy source being necessary.

When a plurality of marks are provided on the body of the device it is advantageously possible to provide for them to be formed with different colours so that the driver recognises the velocity assigned to the mark for example even without a display. The different coloured - 5 refinement can also be provided as a support for a further feature for displaying the velocity.

According to an alternative embodiment, the marks may be formed by a light source, LEDs or an T.CD display.

These types of licit source also permit the mark to be displayed on the w ndscreen or in the field of vision.

The device advantageously has a body with a non- reflective surface in order to permit the at least one mark to be displayed or presented exclusively. In this embodiment, the device is used in particular for mounting on the dashboard, the device advantageously being detachably fastened by bonded corners or a double- sided bonding tape or by being held in the dashboard.

So that the device according to the invention can alternatively be positioned in a field of vision there is provision for the body to be of transparent design.

The body may be embodied as a transparent film or as a transmitted light d splay.

According to a further advantageous refinement of the invention there is provision for the device to be embodied as a trari.parent film which has marks. This transparent film may be positioned, for example, on the windscreen so that this film is arranged in the field of vision of the driver or front seat passenger. In this embodiment, the mark is preferably formed by thin black pairs of lines or thin reflective pairs of lines so that they are not felt to be actually disruptive in the field of vision. This is due, in particular, to the fact that the eye is set to the distance from the person in front and therefore the lines in the near region are not completely perceived. The mark is completely perceived only if it is intentionally focused on in order -to estimate the distance from the person in front. Thc -transparent film is advantageously - 6 attached to the windscreen in such a way that it can be pulled off so that it can be re-applied at short notice and removed again.

This alternative embodiment is preferably arranged on the sun visor or on the inner roof lining of the vehicle near to the windscreen so that it is positioned in the field of vision such that it can be folded or pulled out when necessary. The embodiment of the body of the device as a transparent film or as a transmitted-light display has the advantage - that for the driver the impression is produced that it is only the marks which a-:e positioned in the field of vision and there is no further impairment.

According to one advantageous refinement of the invention there is provision for the marks to be designed for a velocity for estimating the distance by means of at least two vertical lines or by means of at least one horizontal line. By means of the at least two vertical lines or by means of a pair of lines, a region

is displayed which bounds a region in the field of

vision and which corresponds -to a satisfactory distance given a customary width of a lorry of, for example, 1.95 m. The driver detects, by focusing on the lateral external edges of the vehicle, that the distance is satisfactory if these outer edges of the vehicle are covered by the mark or die inside the pair of lines.

As an alternative to the pair of lines it is possible to provide at least one horizontal line whose length corresponds in turn to the width of the vehicle as a function of a sat-.;factory distance at a predefined velocity. The method of functioning corresponds to the mark which is embodied as a pair of lines.

One alternative refinement- of the mark is advantageously provided by means of arrows, triangles or bars which point towards one another and act in a - 7 fashion which is analogous to the pair of lines or the horizontal line.

There is advantageous provision for the width of the marks to define a socalled unsafe region in the form.

Of lines, arrows, triangles, bars or the like. If, for example, the outer edges of the body of the vehicle trave]ling in front are to be seen inside the mark, the driver maintains the predefined distance satisfactorily. As soon as the edges of the body of the vehicle travel] ing in front can be seen inside the width of the marks, it is signalled to the driver that the safe region has now been left and the current distance is in the boundary region. The driver should adopt a larger distance. As soon as the left-hand and the right-hand edges of the body of the vehicle travelling in front lie outside the marks and thus outside the unsafe range, it is necessary to take measures to bring about the satisfactory distance again. It is thus signalled to the driver that he should reduce his velocity, taking into account the traffic behind, in order to assume the safety distance.

There is advantageously provision for a reference mark, for correctly positioning the device with respect to the distance to the driver Is eyes to be provided on the device. As a result, the device can be mounted quickly and easily in or on the vehicle. If the device is not to be used continuously, it can be removed within a short time and then quickly used and oriented again.

According to one advantageous refinement of the invention there is provision for the device to have, in or on the body, a slide which comprises velocity data, and for the slide go be held so as to be moveable within or on the body. A first embodiment of the slide advantageously permits adjustment to different distances to the eyes. A distance between the eyes and the dashboard or tin position at which the device is mounted of, for example, 70 cm is usually provided.

However, if the distance to the eyes deviates from this by a relatively large amount, adaptation can be carried out by means of this slide by adapting the velocity data of the individual marks in accordance with the distance from sitting position. Alternatively, the distance between the pair of lines or the length of the horizontal line can be changed and adapted to the actual distance to the eyes by means of the slide. lO

A further embodiment of the slide advantageously permits the distance from the marks and/or the associated velocity data to be adjusted. Furthermore, different weather conditions and carriageway covering conditions can also be taken into account.

The device is advantageously embodied as a distance estimating templat or distance template which can easily be used by mounting it on the dashboard.

Detachable securing elements are advantageously provided on the template in order to fix it to the

dashboard or in the field of vision and viewing

direction of the driver.

According to a fur her advantageous refinement of the invention there is provision for the size of the mark to be actively adaptable to the vehicle's own velocity.

This makes it possible to provide, for example, a single mark on the body, and said mark follows the current velocity of the driver's own vehicle so that the size of the mark indicates the distance to be maintained in view of the driver's own velocity. For example, the distance between the lines of a pairs of lines is set and changed as a function of the velocity at which the vehicle is travelling at a particular time.

According to a further advantageous embodiment of the invention there is provision that the marks are - 9 - specified, or can be adjusted, as a function of the state conditions of the carriageway. For example, the braking decelerations on a wet carriageway are worse than with a dry arriageway covering. Likewise, the braking decelerations on a tarred carriageway covering can be better than on a metalled or freshly asphalted carriageway covering. The marks can advantageously be adjusted to the corresponding carriageway states by means of a slide and a scale which is arranged on the body so that the driver can adapt the device to the current driving situation. The various braking decelerations on a wet carriageway, dry carriageway, carriageway covering or metalled carriageway covering or carriageway covering which is covered with snow may be determined empirically and characterized on the body of the device so that a simple setting or a change in the distance of the device from the driver's or front seat passenger's eyes takes into account the shorter or longer braking d stance. Likewise, the marks for different state conditions may be permanently predefined for a velocity on the body.

According to one advantageous embodiment of the invention there is provision for at least one display or at least one mark which can be displaced or changed in size to be provided and said display or mark to be adjustable to the current velocity. For example, when the mark is embodied as a display it is possible to display or indicate a certain viewing window by a type of graticule. For example in the case of a transmitted light display it is possible to provide a display by correspondingly actuating crystals by an energizing process.

According to one advantageous development of the invention there is provision for the current velocity of the driver's own motor vehicle to be displayed in the field of vision or on the mark. As a result, the driver can be informed about the current velocity - 10 without distracting his attention from the carriageway, and the driver ca-l thus also check his own travelling velocity.

According to one advantageous development of the invention there is provision for the body to receive information about the current velocity directly or by radio. This allows r for example, the current velocity to be displayed within the region to which the marks are assigned. This also makes it possible to activate only the marks which are associated with this velocity.

Of course, both the corresponding mark and the velocity can be displayed and activated. This makes it possible for the driver or front seat passenger to see only one mark in the field of vision, specifically the one which is adapted to the current travel situation. It is possible, for example, to provide, on the instrument panel component, a row of LEDs which can be activated in pairs and which permit the marks to be displayed, for cxamplc, in the form of lines or bars in the field of vision or to be activated in the field of vision.

The current veloci data is already present owing to the vehicle electronics and can be correspondingly tapped.

The device can also be embodied in such a way that the body is composed of an arrangement of LEDs or the like, which body is supp fed with energy via an accumulator or, for example, v a a cigarette lighter and can be switched on when in use so that the marks are displayed. In the case of transmitted-light LEDs, these

can also be posit oned in the field of vision and

activated.

The marks can advantageously be arranged in such a way that they can be moved and adapted to the driver's own velocity by means of a moveable element, in order to display the satisfactory distance.

The invention and further advantageous embodiments and developments thereof are described and explained in more detail below with reference to examples which are illustrated in the drawings. According to the invention, the features which can be extracted from the

description and the drawings can be applied

individually or several can be combined in any desired combination. In the drawings: Figures la and b show schematic illustrations of a device according to the invention, Figures 2a, b, c show schematic illustrations of inventive alternative embodiments to Figure 1, Figure 3 shows a schematic illustration of a further alternative embodiment to Figure 1, Figure 4a shows a schematic side view of a further alternative inventive embodiment, and Figure 4b shows a schematic plan view of the embodiment according to Figure 4a.

Figure la is a schematic illustration of a first inventive embodiment of the device 11. This device 11 is embodied as a so-called distance template and has a flat body 12 which is formed, for example, from cardboard, multil.ayer paper, a plastic material, wooden material, metal plate or from a composite material or laminate or webs or material which are fused into a plastic foil. The body 12 has a non-reflective surface which its formed, in one preferred embodiment, as a blac-'<-matt surface 13. Marks 14 are provided on the surface 11 which indicate to the driver the velocity of his own vehicle at which a satisfactory distance from - 12 the vehicle travelling in front is maintained. The mark 14 is embodied in the exemplary embodiment according to Figure la by two vertically extending lines 16 as a pair of lines. The lower pair of lines and upper pair of lines are aligned with a common axis 17 which corresponds to the viewing direction in the field of vision of the driver. For example the number 100 is assigned to the lower pair of lines, and the number 60 is assigned to the upper pair of lines. This means that a satisfactory distance is maintained only if, for example, the lateral outer edges of the body of a passenger car travelling in front with a customary width of approximately 1.95 m are provided so as to be congruent with the lines 16 of the pair of lines given a corresponding velocity of the driver's own vehicle of km/in or 60 km/in.

Assuming a typical braking deceleration of, for example, 6m/sec2 and a typical reaction time of 0.6 see, the distance between the lines 16 is calculated according to the formula of the radiation set, according to which f _. Ah

"x" stands for the distance between the lines 16. The letter "w'' is representative of the typical vehicle width of 1.95 m, "f" is the distance of the eyes from the device 11 which is either displayed on the windscreen or positioned in the field of vision and is typically 0.65 m, and "Sb" stands for the braking distance which is calculated according to the formula Sh Y (6 =_: - 13 The letter "v" is the driver's own velocity, "tr" corresponds to the reaction time and "a" corresponds to the typical braking deceleration of 0.6 m/sec2. This calculation formula applies in particular to the estimation of the distance from a travelling vehicle to a fixed obstacle.

The table which is represented below shows, with a velocity of the driver's own vehicle between 30 and 140 km/in/ the braking distance and the distance to the marks (bearing mark distance) under the abovementioned conditions that the reaction time is assumed to be 0.6 s, the deceleration 6 m/s2, the width of the vehicle 1.95 m and the focal length 0.65 m. The same applies to the calculation of the velocity in mph.

Velocity Ve ocity Braking Bearing mark km/in m/s distance distance mm 3n 1 33 = 10.8 111.5 11.11 17.0 _ 74.8 l 50 1 _ 13.89 24.4 _ 51.9 l 60 1 16.67 1 33.4 38.2 1 70 _ 1 13.44 43 2 29.4 22.22 54.5 23.3 25.00 _ 67.1 18.9 _27.78 _ _ 81.0 15.7 30.56 96.5 13.2 I. 33 112.6 11.8 ].30 36.11 1 _ 130.3 9.7.

38.89 149.4 8.5

_

For estimating the distance from a travel.ling vehicle with respect to a vehicle travelling in front, that is to say in flowing traffic, in particular the following formula applies: sb = v(t; + v(1/2a1 - 1/2a2)) + c - 14 The letter sb stands for the braking distance, tr stands for the driver's own reaction time which is assumed to be, for example, 0.5 s, the letter al stands for the deceleration of the driver's own velocity which is assumed to be, for example, 6 m/s2, and the letter a2 stands for the deceleration of the vehicle travailing in front, assumed to be a value of, for example, 9 m/s2. The width c.' the vehicle which is assumed to be 1.95 m, and the distance from the eyes which is assumed to be 0.65 m remains the same as in the example above.

The constant C is assumed, for example, to be 3.5 m, said constant representing type of safety distance or comprising a variable which defines the distance for the two stationary vehicles.

The following table shows the available braking distance for the driver's own vehicle for velocities between 30 and]40 km/in in comparison with the vehicle travelling in from', and the distance to the marks under the abovementloned conditions. This overview also applies analogousl-- to mph and just needs to be converted.

Velocity Velocity Braking Bearing mark km/in m/s distance distance mm m _. _ _ _ 8.33 _9.6 132.1 1._11 12.5 _ 101.5 13.89 15.8 80.2 _60 16.67 _ _19.5 64.8 _ _70 lq.44 _23.7 53.4 __ 2.22 _ 28.3 _ 44.7 2.00 33.4 38.0 _ 27.78 38.8 32.6 30.56 44.7 _ 28.3 33.33 51.0 _ 24.8 230 36.11 57.88 21.8 _ 38.89 _ 65.0 19.5

_

There is advantageously provision for corresponding devices to be made available, for example, with adaptation to the braking deceleration of the driver's own vehicle, so that the characteristic properties of the driver's own vehicle, in particular braking decelerations which are correspondingly adapted to the braking deceleration and/or the character property of the driver are taken into account and transferred to the distance between the marks.

The numbers and the velocity data on the device 11 are provided in mirrorinverted fashion so that the data can be read when it is displayed on the windscreen.

When a plurality Of pairs of lines are provided on a device 11, the mark 14 for the relatively high velocity is advantageously provided in the lower region, and the mark for the relatively low velocity is provided in the upper region.

The marks 14 can also have an additional function according to whic:- a satisfactory distance and an illegal distance are displayed. This may be provided, for example, by means of wide marking lines, the width of the marking lines indicating the illegal region.

Likewise, a pair of thin lines may be provided within the further marks, the thin lines indicating that the satisfactory distance is no longer present and the region of the illegal distance has been reached. As soon as the thick marks are reached or exceeded, the distance is too short in whatever way. This exemplary embodiment can also be transferred analogously to all

the other examples.

Figure 1b illustrates a plurality of marks 14. For example the individual marks 14 can also be assigned to one another in pairs and partially overlap one another.

As a result, transition regions of the driver's own velocity with respect to the distance to be maintained - 16 can also be estimated.

In one alternative embodiment of the invention according to Figure 2a, the marks 14 are represented in the form of a tar. In. addition, marks which are arranged below the number 30 in a V shape, and which serve as additional help marks, are provided by way of

example.

A further alternative arrangement of the mark 14 is provided in Figure 2b. For example, the vertically extending lines 16 can be formed with a different colour than the mark sections which extend obliquely outward and which connect the vertically extending lines 16 to one another. This embodiment has the advantage that a type of corridor is formed. If the vehicle travelling in front is located within this corridor, the distance is satisfactorily maintained at the mark 14 which corresponds to the driver's own 2Q velocity.

Furthermore, alternative embodiments of marks 14 are illustrated in Figure 2c. These may comprise, for example, cross sections in the form of an arrow or triangle, as illustrated on the left, or other cross sections, as illustrated on the right. An inverse embodiment of the surface 13 and of the marks 14 with respect to the embodiments illustrated in Figures 1 and 2 is also conceivab e.

The marks 14 are advantageously formed from fluorescent material. These are, for example, bonded on or laminated in. A brief exposure to the light is sufficient to perm, a display over a relatively long period at night.

One preferred embodiment of the device can be manufactured by means of printing technology. For example, the mark 14, which comprises reflective, - 17 fluorescent, phosphorescent or electroluminescent substances, is printed onto a piece of matt-black cardboard. Alternatively it is possible to provide for the velocity bars or lines]6 which are arranged in pairs to be printed onto a transparent film. This may be lo ated under the sun visor and be folded down when necessary or pulled down and moved to eye level, like the tongue of a slide rule. For this purpose, the distance between the lines 16 can be calculated with respect to a changed eye distance in the same way as described above.

A further alternative embodiment of the invention consists in the mark being embodied with a reflective, fluorescent, phosphorescent or electroluminescent substance over its entire surface. Said substance is

displayed in the field of vision. Owing to the

transparency, the vehicle travelling in front can be recognized, allowing the person to make a simple and rapid estimation. inis alternative embodiment can also be provided for use on a sun visor by virtue of the fact that the mark over the entire surface is provided by a printed boundary on the transparent film. This printed boundary can be formed by a frame or a surrounding surface which is composed of a large number of small dots or thin lines which are spaced apart from one another and which, on the one hand, bound the mark, but also do not significantly obstruct the view through them.

A further alternative refinement of the invention is illustrated in Figure3. If the distance from the eyes of individual persons differs from a customary distance of, for example, 70 cm by more than 10-Oo-, a corresponding adaptation can be made by adjusting a slide 21 to furthceye distance values 22. In the exemplary embodiment illustrated in Figure 3, the associated velociLv is correspondingly changed so that the permanently set distance between the lines 16 is in - 18 turn assigned to a specific velocity of the driver's own vehicle.

Alternatively it is also possible to provide, depending on the distance from the eyes, for the bars to be adapted to one another in the lateral distance for a predefined velocity. This may also be done by means of slides. As a result, for example, characteristic velocities such as 50 km/in for town traffic, 100 km/in for a country road and 130 km/in as a guideline velocity on a motorway are Detained as display and the distance between the dines 16 is adapted.

The embodiments described above represent a passive estimation aid. With this estimation aid, the driver firstly obtains information about his own velocity, which he reads from the speedometer. After this, the driver focuses on the mark 14 which is correspondingly positioned in the l eld of vision, and he can correctly detect whether the vehicle travailing in front can be seen inside or outside the mark. If the vehicle or its lateral edges lie Aside the mark, the distance is too short. If the outer edges of the vehicle coincide with or lie inside the Mark, the distance is sufficient. In the case of relatively wide vehicles, for example buses or lorries, the ta l lights of these vehicles may be used for orientation, in order to carry out the method for estimating the distance from a vehicle travelling in front in the same way.

Furthermore, accorc:ing to the invention an active device 11 is provided which is illustrated, for example, in Figures 4a and b. This device 11 comprises a body 12 in which a circuit 25 is provided. This circuit 25 receives signals about the current velocity via radio or cable from a speedometer. The circuit 25 activates, for example, two of six electromagnets which are arranged at pl determined positions underneath a displaceable clip ii of the body 12. A thin wire 33 - 19 made of iron, which has a fluorescent coating in the passive state, is provided above two displaceable clips 32. As soon as a certain velocity has been reached, the circuit is activated, causing energy to be fed to the wiring in order to excite the fluorescent radiation.

Alternatively it is possible to provide for in each case the circuit 25 to drive a motor which positions two clips 32 as a function of the detected velocity for lO the axle 11. This setting or this adaptation may be carried out continuously or at freely selectable time intervals. In the case of continuous adjustment, the lines l6 are adjusted directly to the current velocity, whereas when updating is carried out within specific time intervals the lines 16 are adjusted to the velocity which is averaged within the interval.

According to a further alternative embodiment of the invention there is provision for this device It to be provided as a fixed installation in a dashboard or to be retrofittable to the dashboard. In this context it is possible to provide, for example, a display or a device ll with a plurality of LEDs which form the marks and project into the field of vision. These LEDs may be, for example, of bar-shaped design and be arranged in parallel one next to the other so that, by activating them in pairs, a zone within which the distance is satisfactory is displayed in the field of vision. When this device ll is not in use it may be arranged behind an opening in the dashboard and may be designed to project the marks 14 onto the windscreen through an adjustable lid or housing section. At the same time, the device It may be provided in the dashboard in such a way that it can be displaced or adjusted so that adaptation to the actual distance from the drivers eyes is made possible.

Alternatively it is also possible to provide for the windscreen to have regions which can be activated by - 20 current in order to display the bars. It is also possible to provide for a film to be bonded onto the inside of the windscreen, the film comprising zones with quartz crystals or LF.Ds so that in turn the individual marks can be made visible to the driver by appropriate actuation.

Claims

Claims 1. Device for estimating a distance from a vehicle travelling in

front or an obstacle, having a body (12) which has at least one mark (14) for estimating the distance as a function of the vehicle's own velocity, the at least one mark (14) being arranged or displayed

in the field of vision of a person in a vehicle.
2. Device according to Claim 1, characterized in that a plurality of marks (14) are provided on the body (12) and an associated velocity data item is positioned between the marks or in a,way which is assigned to the marks.
3. Device according to Claim 1 or 2, characterized in that a plurality of marks (14) are provided on the body (12) and are lined along a common axis (17) which corresponds to the viewing direction of the driver.
4. Device according to one of the preceding claims, characterized in that the at least one mark (14) is arranged on the body (12) one behind the other along an axis (17), and the mark (14) for the highest velocity is arranged in the lower region and the mark (14) for the lowest velocity is arranged in the upper region of the body (12).
5. Device according to one of the preceding claims, characterized in that the at least one mark (14) is - 22 formed by fluorescent, phosphorescent and/or electroluminescent substances.
6 Device according to one of the preceding claims, characterized in that the at least one mark (14) is formed by at least one light source, an the LED and/or an LCD display.
7. Device according to one of the preceding claims, characterized in that the body (12) has a non- reflective surface (13).
8. Device accord ng to one of Claims 1 to 6, characterized in that the body (12) is designed so as to be transparent as a transparent film or as a transmitted-light display, or in that the body is positioned as a film which is attached to the windscreen.
9. Device according to Claim 8, characterized in that the body (12) is positioned on a sun visor so that it can be folded or pu: leaf out.
10. Device according to one of the preceding claims, characterized in that the at least one mark (14) is formed for a velocity by at least one horizontal or two vertical lines (16).
11. Device accorc;.ng to one of Claims 1 to 9, characterized in that the at least one mark (14) is formed by arrows, triangles, bars which are spaced apart from one another and point to one another.
12. Device according to one of Claims 1 to 9, characterized in that the at least one mark (14) is formed by the display of velocity itself.
13. Device according to one of the preceding claims, choral Prized in that a reference mark is provided - 23 which indicates In orientation with respect to a predefined distance to the eyes.
14. Device according to one of the preceding claims, characterized in that the body (12) has a slide (21) which has velocity data and is held so as -to be moveable within the body (12) and is adjustable to different distances to the eyes.
15. Device according to one of Claims 1 to 13, characterized in that the body (12) has at least one slide which has marks (14) and is held so as to be moveable within the body (12).
16. Device according to Claim 15r characterized in that the slides have marks for different velocity ranges or ground covering states.
17. Device according to one of the preceding claims, characterized in that the body (12) is embodied as a distance template which is preferably detachably fastened to an instrument panel component of a vehicle.
18. Device according to Claim 1, characterized in that the mark (14) is Of variable design and is actively adapted to the vehicle's own velocity.
19. Device according to Claim 17, characterized in that at least one display or at least one mark which is displaced or varied in size is provided, it being possible to adjust he size or distance thereof to the current velocity in order to estimate the distance.
20. Device according to Claim 17 or 18, characterized in that the vehic]. e's own velocity is displayed in the

field of vision or al the mark (14).
21. Device according to one of Claims 17 to 19, characterized in that the body (12) is embodied as a - 24 housing and comprises at least one circuit (25) which converts the current velocity to a signal for positioning the mark (14).
22. Device according to Claim 20, characterized in that the body (12) has at least one driven and displaceable element which holds at least one mark (14) or is part of a mark (14) and is adjustable, by methods, to the distance calculated by the circuit (25).
23. Device according to Claim 21, characterized in that the displaceable element is embodied as a slide with a wire which has a fluorescent coating.
24. Device according to one of Claims 17 to 22, characterized in that the mark (14) is formed from a

field composed of a plurality of LEDs.
25. Device according to one of Claims 17 to 23, characterized in that the adaptation of the mark (14) to the vehicle's own velocity is provided continuously or in freely selectable time intervals.
26. Device according to one of the preceding claims, characterized in that the marks (14) are arranged in the field of vision of the driver and/or of the front seat passenger.
27. Device according to one of the preceding claims, characterized in that the body (12) receives information about the current velocity directly or by means of radio or]R radiation.
28. Method for estimating a distance from a vehicle travailing in front, in particular by means of a device according to Claims] to 27, in which at least one mark (14) is displayed in a field of vision between a driver and a vehicle to elling in front, in which the - 25 - vehicle's own velocity is registered on the speedometer or displayed in the field of vision, and in which the mark (14) which is provided is focused open as a function of the vehicle's own velocity and the current distance can be estimated in a specific fashion at least by comparing the width of the vehicle travelling in front in conjunction with the associated mark (14) which is orientated as a function of the velocity.
29. Device for estimating a distance from a vehicle travelling in front of an obstacle constructed and adapted to operate substantially as described herein with reference to the accompanying drawings.
30. Method for estimating a distance from a vehicle travelling in front substantially as described herein.