Acoustic modulation of road surface

Abstract

Methods for arrangement of studs or dents over the road surface in a way that when a vehicle passes on the road, a desired sound that is dependent on the driving speed and the arrangement and properties of the studs or dents is generated into the vehicle. The studs or dents are attached to the road and used to pass audio information such as warnings to the driver.

Description

This invention is based on and claims the benefit of Provisional Application No. 60/541,324 filed Feb. 1, 2004.

TECHNICAL FIELD

The present invention relates to an acoustic modulation system for road surface, in a way that a required sound is generated when a vehicle is passing by.

BACKGROUND

Marking on roads has been useful method ever since to interact with the driver of a vehicle. Colored marks are used to mark the road side, and as signs to drivers. Another method of warnings is the bumpers that may be placed in different locations in the road to warn the driver for reducing speed, getting out of the lane etc.

U.S. Pat. No. 4,203,685 describes semi circular cross section secured to the roadway, that is molded from electrometric plastic. When the vehicle drives over the speed arrestor, the resiliency provides a forward thrust to the vehicle. U.S. Pat. No. 4,362,424 describes a speed bump, provides controlled force to the vehicle according to the speed of the vehicle. The main problem with the above methods is that the use of speed bumpers causes the vehicle to vibrate and expose the driver to a dangerous is high speed.

U.S. Pat. No. 5,106,226 describes warning system for vehicle to be used for temporary installation on highway. The warning system is comprised from a supporting base that is located to enable the vehicle wheels to pass over, and a multiple speed bump unit. U.S. Pat. No. 5,327,850 describes low cost roadway marker with a constant cross sectional shape that provides a physical rambling cue together with reflective cue. The use of that method is also problematic because of the vibration of the vehicle. U.S. Pat. No. 6,547,484 is a patent about cutting rumble strips in road surface, in order to warn drivers about getting out of the lane or other warnings. The main problem with the visual warning method is that it is not working when the visibility is not good

U.S. Pat. No. 5,769,563 describe highway-warning device that can be easily installed and removed. The device is composed from studs and dents in a way that when a wheel is passing over, it provides audible sound and slight vibration to warn the driver. While this method of warning does not cause vibrations, it is able to generate limited information to the driver.

There are other patents known in the prior art to have markers that has special properties in order to supply the vehicle with guidance system: U.S. Pat. No. 5,853,846 is a magnetic road marker that may send signals to a sensor within a vehicle to use vehicle guidance system. U.S. Pat. No. 6,414,606 is a method of adding radioactive material to road marking paint in order to be used as guidance to a vehicle. That system may be used for guidance only, and requires expensive equipment within the vehicle.

Even so the known art provides the tools for basic communication between the vehicle or the driver by means of vibration or sound warning, visual road signs from many kinds, and special materials that embedded in the paint for guidance, the amount of information that the driver can get from the road is very limited.

The current invention deals with acoustical modulation of the road in a way that the driver gets acoustical information with many different meanings, and therefore provides great advantage over the conventional concepts.

SUMMARY

This invention is about adding acoustics modulation to roads of any kind, so they will generate acoustic information to and from vehicles that passing on the road.

The acoustic information may be audible to the passenger's ears, to a sensing electronics within the vehicle or sensing electronics outside of the vehicle. The acoustic information may include constant information such as identification on the road name, lane kind, directions, speed allowed, commercials and so on. The information may include also controlled changing data.

The acoustics information may be generated in analog audible data or digital data format, and may be in any kind of modulation. The modulation of the road surface is used for warning the driver of dangers on the roads, to point of right or left directions, to make statement regarding to the distance from junctions, information about speed and so on. Another use of the acoustical signs is to give the passengers information about the road, environmental conditions, directions etc. The acoustical signs may express by means of agreed acoustical sequences, tones or speech.

The acoustic information is generated when a vehicle meets studs or dents on the road while driving. Pre arrangement of those studs or dents on the road cause a desired acoustical signal to be generated. This acoustical signal is sensed inside the vehicle as well as outside the vehicle.

One embodiment of the invention is the Analog road surface modulation, in which the arrangement of the studs or dents is in a way that each stud or dent has different properties that represents different kind of acoustic signal. When the wheel of a vehicle hit the studs or dents with the different properties, in the pre-arranged sequence, the combination of the different acoustic signals form the required sound depending on the vehicle speed.

Another embodiment of the invention is encoding digital data using different properties of suds and dents. In this case the rate of the encoded digital data is dependent very much in the speed of the vehicle and the data shall include special well known in the art encoding methods such as reed-solomon algorithm, that is known to those familiar with the art, that allow detection and use by equipment that is within the vehicle.

Another embodiment of the invention is the use of the sound generated from the vehicle hitting the studs or dents, by equipment located on the road surface, or near by the road surface, that collects data on the number of vehicles, the speed and the size of the vehicle that passes by for statistics or data collection purposes.

Another embodiment of the invention is modulation of the required signal using different smoothness areas over the road surface. Those different surfaces generate different acoustic signals when the wheel of a vehicle passes by. Arrangement of the different smoothness areas in a certain method creates a required acoustic signal.

In another embodiment of the invention the acoustic signal that is a result of the hit of the wheel in the stud or dent is described as an acoustical impulse response. The difference in height between two consequent studs or dents represents the intensity of the hit and therefore the intensity of the acoustics impulse response within the vehicle. In a certain arrangement of consequent different height studs or dents, the required acoustical sound is generated when the wheel hit's the stud or dent. That emitted acoustical sound is dependent on the speed of the vehicle.

Another embodiment is the use of the properties of the acoustical impulse response that is a result of the mechanical hit of the wheel and the stud or dent. Arranging the stud or dent over the road surface in such a way the when a vehicle pass by, the sum of the acoustical Signals from each stud or dents at a curtain speed of the vehicle generates acoustical signal close to sinus within the vehicle, at a frequency that is dependent on the impulse response characteristics. Changing the width in time of the acoustical response is by the arrangement of very close to each other studs or dents. Implementing groups of studs or dents that are arranged for wide in time impulse response in a certain order generates controlled frequency acoustics sinus signal within the vehicle.

Another embodiment of the invention is the use of the vehicle wheel's width to cover at the same time number of studs or dents with or without phase delay between each other. With this arrangement, it is possible to set up studs or dents on the road surface that effect with a very low delay between consequent acoustical impulse responses. That arrangement is effective in all modulation methods within this patent.

Another embodiment of the invention is to modulate number of sinus signal on the road surface that together combines the required sound. The signals can be sourced all in the same wheel or can be sourced from different wheels and acoustically summed with the vehicle. Each sinus signal represents another frequency range, using the wide impulse response method. The frequency and amplitude controlled sinus signals produced by the sequence of impulse response as explained above. The generation of number of sinus signals at the same time is by consequent studs or dents that arranged on the road surface in a certain way, enables the vehicle wheel to cover number of studs or dents at the same time. Sum of the different sinus signal within the vehicle space, recreates the required sound that is a combination of sinus signals.

The current invention describes a road that is fully covered with stud or dents, in a way that when a vehicle is in a lane, the acoustic signal is emitted no matter of the vehicle location within the lane.

Another embodiment of the invention is generation of meaningful sound signal within a vehicle that is composed from number of narrow bandwidth signals that are modulated in one of the modulation methods that are described above. In this embodiment, the studs or dents are spaced in a distance one from each other that represent a fixed sampling rate, regardless of the acoustical impulse response as presented before. The acoustical impact of the noise generated from the studs and dents when a vehicle pass over, is summed within the vehicle and reconstruct the required sound.

Another embodiment of the invention is generation of meaningful sound signal within a vehicle that is composed from number of narrow bandwidth signals that are modulated in one of the modulation methods that are described above. In this embodiment, the studs or dents are spaced in a distance one from each other that is relative to the frequency of the current narrow bandwidth signal to enable the required number of samples for each frequency that will enable reconstruction of the signal. The acoustical impact of the noise generated from the studs and dents when a vehicle pass over, is summed within the vehicle and reconstruct the required sound.

In another embodiment of the invention and in cases were the total signal is composed of number of narrow bandwidth signals, the intensity of the different low bandwidth signals, that are represented by studs and dents, is set us to compensate on the acoustical pass between the wheels of the vehicle and the vehicle interior.

Another embodiment of the invention is representing the intensity of the acoustic signal, by the means of changing the studs or dents width, in the area that they hit the wheel. In this embodiment all studs or dents with the same height represent different acoustic intensity corresponds to their width.

Another objective of the invention is measurement of traffic behavior by acoustical means and by analyzing of the sound that is generated from a vehicle passing by, to measurement equipment over the road. The special arrangement of studs and dents can assist in determination of the vehicle speed, the wheel size and other parameters of the vehicle, as well as determination of the traffic load.

BRIEF DESCRIPTION OF DRAWINGS

Various other objects, features and attendant advantages of the present invention will become fully appreciated as the same becomes better understood when considered in conjunction with the accompanying drawings wherein:

FIG. 1 is a description of simple analog modulation of a signal over the road surface, that is composed of suds or dents.

FIG. 2 is a description of simple digital modulation of a signal over the road surface, that is composed of suds or dents.

FIG. 3 is a description of simple smoothness modulation of a signal over the road surface.

FIG. 4 is a detailed view of the arrangement of studs or dents over the road surface, and the method of reproduction of the desired acoustical effect within the vehicle FIG. 5 is a view of the vehicle hits the stud or dent and the resulted acoustic impulse response within the vehicle.

FIG. 6 is a view of a pre arranged sequence of studs or dent and the acoustical impulse response effect that is narrow bandwidth desired acoustical signal.

FIG. 7 describes special arrangement of the studs or dents over the road surface, to produce wide acoustics impulse response.

FIG. 8 is an arrangement of groups of studs or dents over the road surface that enables generation of narrow bandwidth acoustical signal within the vehicle

FIG. 9 describes arrangement of the studs or dents over the road surface that arranged with phase delay.

FIG. 10 is apparatus for acoustical signal generation that is built of more then one narrow bandwidths signals.

FIG. 11 is top view of a road that is covered with signs according to this patent in a way that the signs are effective over the width of the road.

FIG. 12A is reproduction of acoustical signal built from narrow bandwidth signals where the distance between studs or dents is dependent on the main frequency of the narrow bandwidth signal and the modulation is amplitude modulation.

FIG. 12B is reproduction of acoustical signal built from narrow bandwidth signals where the distance between studs or dents is constant and the modulation is amplitude modulation.

FIG. 13A is reproduction of acoustical signal built from narrow bandwidth signal where the distance between studs or dents is dependent on the main frequency of the narrow bandwidth signal and the modulation is width modulation.

FIG. 13B is reproduction of acoustical signal built from narrow bandwidth signals where the distance between studs or dents is constant and the modulation is width modulation.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Amplitude modulation on road surface is demonstrated in FIG. 1. The wheel 101 of the vehicle is rolling towards direction 102. The studs or dents 103a . . . 103n have different properties regarding the required sound. In FIG. 1 the studs or dents 103b is larger in diameter then 103a, and therefore represent different sound when the wheel pass by. The studs are built into the road or lay over the road in a way that when a vehicle pass by, the amount of vibration that is generated is minimal and the main effect is the sound that is generated with a sequence of more then one stud, that arranged in different methods as will be demonstrated. The sound may represent special acoustical signs to the driver, warning sound, sound effects and speech. The dents are built as well in a way that generate minimum vibrations to the vehicle and the main effect is the sound that is composed of the effects of hitting in more then one dent. Arrangement of the different size of studs or dents generates the required sound with the wheel passing by with the correct speed. In one embodiment of the invention, the studs or dents are arranged throughout the road width and the sound is implemented to a vehicle anywhere on the road. This method may be used also to encode digital data over the road surface. FIG. 2 shows digital data encoding over the road surface. There are two different properties of studs or dents that generates different sound when the wheel passes by stud or dent 203 versus stud or dent 204. The data is arranged in a way that acoustic receiver that is placed within the vehicle can detect the sound and decode the data from it as the vehicle passes by. At the same way acoustic receiver can be placed near-by the road surface in order to sense and analyze the sound of the vehicle as it passes by. This method is useful For example, for traffic measurement purpose. The shape of the studs or dents may be any shape not only circle as the drawing suggests.

The analog and digital effects can be accomplished also with applying different levels of smoothness to the road surface. While each level of smoothness generate different sound when touching the wheel.

FIG. 3 illustrate such road shaping with different smoothness area's that required generating the required sound. The wheel 301 is moving in the direction of the arrow 302. The different surface smoothness 303a-303d are made in a way that each of 303a-303d is generating different sound when the wheel pass over. The area's 303a-303d may be shaped in any shapes and can be designed to generate different sound to different wheels at the same vehicle, depending on the speed of the vehicle.

FIG. 4 shows another modulation method. The wheel 401 is moving in the direction 402 and hit the small studs or dents on the road 405,406,407,408,409,410 and 411. The height of wheel 401 bottom from the surface 404 is depended on the position of the wheel on the road and the combination of the studs that supporting the wheel at a certain position. As the wheel rolls and hit studs 405 . . . 411 a series of impulse response is generated to the cabin and causes the acoustical effect 419 in the driver's ears. The acoustical effect 419 is the acoustical sum of the impulses caused by the wheel hitting studs 405 . . . 411. The acoustic intensity of the acoustical effect 419 is directly controlled by the intensity of the impulse cause by the hit of the stud with the wheel. The intensity of the impulse caused by certain stud is controlled by the difference between the level of the wheel 401 above the surface 404 before hitting the stud and the level of the stud. Stud 406 is at the same level of stud 405, and therefore the wheel's 401 level is not changed when passing by. When the wheel hits stud 407 that is with higher level, then high intensity impulse response 414 is generated. Stud 408 level relative to the wheel is double then as in the case of stud 407 and therefore the impulse response 415 intensity is growing with the same proportion.

Stud 409 levels relative to the wheel bottom before hitting the stud, and is the same as it was in stud 407 and therefore the intensity of the impulse response 416 is the same as the intensity of the impulse response 414. Stud 410 is in the same level of stud 409 and so the wheel's level does not changed, and therefore the intensity is the same as in the impulse response 413. Stud 411 has a negative level difference and so the intensity of the impulse response 418 is increasing accordingly. The same effect as described in FIG. 4 may be achieved with width or shape modulation (FIG. 1). In this case the studs has different width that causes different impulse intensity to the wheel and as a result a change of the acoustic intensity within the cabin.

The road noise is detected at the cabin, as a result of an impulse response, while the sources of the impulse is the hitting of the wheel on the road surface. The modulation principle is to use this impulse response mechanism in order to generate the required sound. In FIG. 5 the vehicle 501 is going in the direction of the stud 502. When the wheel 505 hit the stud, acoustical impulse response 503 is generated to the vehicle cabin, that been heard by the vehicle driver. The stud 502 is built in a way that it's side 506 that is facing towards the wheel, will generate relatively high intensity impulse when hitting the wheel 505, while the other side 507, will cause a relatively low intensity impulse when the wheel 505 leaves the stud. That effect is achieved by controlling the height and the width or shape of each side of the stud.

FIG. 6 shows a sequence of stud with distance of 603 between stud edges. All of the edges are at the same height from the road surface 605. When the wheel 604 hits the stud 602a, 602b and 602c with a time delay, the result is a sequence of acoustical impulse response 606a, 606b and 606c that sensed by the driver. The distance between edges 603 is computed in a way that the consequent delayed acoustical impulse responses at certain vehicle speed will be narrow bandwidth signal that is close to a sinus signal. The acoustical sum of the impulse response 607 has many harmonies and frequencies built in but with one dominant frequency that is differentiated very easily by the driver. The frequency is determined by the impulse response 606a characteristics, the distance 603 between studs and the speed of the vehicle. The acoustics impulse response 606a is the first acoustical component of the narrow bandwidth signal within the vehicle. The acoustics impulse response 606b that is delayed in time is acoustically summed with the acoustics impulse response 606a to form the narrow bandwidth signal.

The generation of narrow bandwidth signal is done by predetermined of sequence of studs and dents that applied to the road as describes in the amplitude modulation above. This signal sequence audible frequency is depended upon the speed of the vehicle. The narrow bandwidth signal amplitude is controlled the stud of the salient or coating of the road. The intensity of the narrow bandwidth is determined by the actual height of each stud 602b, 602c, 602d etc.

FIG. 7 describes a method for generation of low frequency using a series of repetitive impulses.

The vehicle 701 is driving to the direction of the studs or dents on the road 703a, 703b, 703c and 703d. The distance between studs is 702 that is very small and the group generates a wide acoustical impulse response 705 that is built up from the many consequent impulses 704a, 704b, 704c and 704d.

FIG. 8 describes how to generate low frequency narrow bandwidth signal from the wide impulse response. The vehicle 801 is driving towards the series of studs 802a, that is built to generate wide acoustical impulse response when the vehicle pass by the studs or dents at a certain speed. When the wheel 805 hit the stud 802a a wide impulse response 805a is generated. The distance 804 is calculated in order to enable generation of narrow bandwidth signal 806 from a series of impulse responses 802a, 802b, 802c. The intensity of the narrow bandwidth signal is determined by the height of the series 802a, 802b, 802c from the road surface 803.

Another method of generating wide impulse response signal is described in FIG. 9. The studs 902a, 902b, 902c . . . 902n are arranged in a phase delay on the road surface. When the wheel 901 hit the studs 902 a series of close impulse response is generated, that results in a wide impulse response. A series of phase delay studs 902, 903 and 904 are arranged with a distance 905 that is calculated to generate a narrow bandwidth signal as results of the consequent studs 902, 903, 904. The method that is explained here in drawing 9 may be used to set up the studs or dents with reduced distance between each other and at the same time keep on the required physical size of the studs or dents on the road. The modulation technique may be height where different height describe different level, or with the another method where the heights is the same for all studs or dents but the width of each stud describes different level, in a way that when the wheel hits different width studs, a different acoustical impulse response is generated. In both cases the height modulation or the width modulation, the modulation is actually influencing on the intensity of the acoustical impulse.

FIG. 10 shows a method of generating sound that is composed from many frequencies, based on narrow bandwidth signal generation that is composed from sequence of impulse response or that is composed of sequence of wide impulse response.

The wheel 1001 is going in the direction 1002 of the group of studs 1007. The group 1007 is composed of studs, each of them is composed from different width impulse generator, 1003, 1004, 1005. The result is number of different frequency narrow bandwidth signals 1006a, 1006b and 1006c. The narrow bandwidth signals are acoustically summed in the vehicle cabin, and perform a required sound signal.

Controlling the height of the studs or dents from the road surface, controls the intensity of the impulse generates by the wheel hitting the road height sets up the intensity of each narrow band signal. Using the method of groups that represent narrow bandwidth signals make it easy to compensate on the transfer function from the road to the vehicle inner, that has different gain for different frequencies. The compensation is done giving different intensity to different narrow bandwidth signal, were the narrow bandwidth signal is the acoustical signal that result from the sequence of studs or dents.

Controlling the width of the studs or dents from the road surface, controls the intensity of the impulse generates by the wheel hitting the road height sets up the intensity of each narrow band signal. Using the method of groups that represent narrow bandwidth signals make it easy to compensate on the transfer function from the road to the vehicle inner, that has different gain for different frequencies. The compensation is done giving different intensity to different narrow bandwidth signal, were the narrow bandwidth signal is the acoustical signal that result from the sequence of studs or dents.

FIG. 11 describes one embodiment of the invention over a road surface. The Vehicle 1101 is driving on the road 1103 that is covered with group of studs 1105a, 1105b . . . 1105n. The groups are very close one to another and cover one portion of the road width up to the entire road width between the road margins 1102. The group of studs is charring acoustical information to the driver of the vehicle that is meaningful at a curtain speed. The vehicles wheels 1104 transfer the information. If a wheel is not positioned correctly on the group of studs, some distortion affects on the recovered signal within the vehicle since not all of the frequencies are summed.

FIG. 12A is a method of generating meaningful sound signals in the cabin of a vehicle, that is composed of narrow bandwidth signals of higher frequency then the vehicle natural impulse response 503 of FIG. 5. The wheel 1201 is going in the direction 1202 towards the group of studs 1203. The group is composed of different frequency narrow bandwidth signal generators 1204a, 1204b and 1204c. The distance 1205a, 1205b and 1205c between the edges of the studs is determined according to the required frequency, with ignorance of the impulse response properties in the following way: The required number of samples per one narrow bandwidth signal cycle is chosen and this number is valid for all of the frequencies and so in different main frequencies of the narrow band signals, the distance 1205a, 1205b and 1205c are different. As a result, whenever the wheel 1201 hits a stud, it generates impulse and so a series of impulse responses in the different frequencies is acoustically generated, each with acoustical intensity that is control by the intensity of the hit. The intensity of the hit is controlled by the difference between the stud level of the wheel from the road surface and the stud that caused the hit. The group's 1204a 1204b and 1204c generates different frequency of narrow bandwidth signals. All of the signals are acoustically summed within the cabin. The level of each narrow bandwidth signal is determined by height width or shape of the studs or dents.

FIG. 12B describes another embodiment for generating meaningful sound signals that is composed from separate narrow bandwidth signals in high frequency. The wheel 1201 is going in the direction 1202 towards the group of studs 1207. The group is composed of different frequency narrow bandwidth signal generators 1206a, 1206b and 1206c. The distance 1208 between the edges of the studs is constant for all narrow bandwidth signal frequencies and regarded as sampling frequency. The intensity of each stud is set up to achieve the narrow bandwidth signal effect. The groups 1204a 1204b and 1204c generates different frequency of narrow bandwidth signals. All of the signals are acoustically summed within the cabin. The level of each narrow bandwidth signal is determined by height width or shape of the studs or dents.

FIG. 13A describe a method of modulation based on width modulation. Each line of 1304a, 1304b and 1304c, represent different narrow bandwidth signal. All of the signals are summed at the driver's ears to create a complete data. The different width of the studs or dents represents different acoustical intensity. In this case the distance 1305 between the studs or dents is related to the main frequency of the narrow bandwidth signal and so the distance 1305 of the narrow bandwidth 1304a, is shorter then the distance 1305a, that corresponds to the signal 1304c that represents lower frequency. All studs or dents generate acoustical noise when the wheel 1301 hits them.

FIG. 13B describe a method of modulation based on width modulation. Each line of 1306a, 1306b and 1306c, represent different narrow bandwidth signal. All of the signals are summed at the driver's ears to create a complete data. The different width of the studs or dents represents different acoustical intensity. In this case the distance 1308 between the studs or dents is equal for all narrow bandwidth signals. All studs or dents generate acoustical noise when the wheel 1301 hits them.

With respect to the above description then it is to be realized that the optimum dimensional relationship for parts of the invention, to include variations in size, arrangement and relationship and manner of operation, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described, are intended to be encompassed by the present invention.

Therefore, the forgoing is considered as illustrative only of the principle of the invention. Farther, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

1. System for generation of a required audible sound within a vehicle passing on road surface, said system comprising of low profile studs or dents in any shape that are pre arranged over the road surface.

2. System for generation of a required audible sound within a vehicle passing on road surface, said system comprising areas of different smoothness that are pre-arranged over the road surface.

3. The system according to claim 1 wherein modulation is used to modulate analog information or digital information with the audible sound.

4. The system according to claim 1 wherein the studs or the dents are designed to cause minimum vibration in the vehicle and maximum acoustic sound.

5. The system according to claim 1 wherein the studs or the dents are spread all over the road width in a way that vehicle gets the acoustical data regardless of its position.

6. The system according to claim 1 wherein the studs or the dents are located in part of the road width in a way that vehicle gets the acoustical data according to its position.

7. The system according to claim 1 in which the studs or the dents are remotely controlled and are adapted to change characteristics such as shape, width or height.

8. The system according to claim 1 wherein modulation intensity is expressed by controlling the height of the studs or dents.

9. The system according to claim 1 wherein modulation intensity is expressed by controlling the shape of the studs or dents.

10. The system according to claim 1 wherein modulation intensity is expressed by controlling a width of a contact area between the wheel and the studs or dents.

11. The system according to claim 1 wherein contact between the wheel with the stud or depression causes an acoustic impulse response that is to modulate a required sound signal within the vehicle.

12. The system according to claim 11 wherein a series of studs or dents with different modulation intensities are positioned in such a distance that when a vehicle passes at a certain speed, a narrow band acoustic sound is detected within a vehicle whose frequency is dependent on the vehicle speed.

13. The system according to claim 1 wherein a series of studs or dents are positioned in such a distance between each other that when a vehicle passes at a certain speed, a wide acoustics impulse response is generated whose duration depends on the number of studs or dents, and which is used to modulate a required sound signal within the vehicle.

14. The system according to claim 13 wherein a series of wide impulse responses with different intensities is arranged in such a way that when a vehicle passes at a certain speed, a narrow band acoustic sound is detected within a vehicle whose frequency is dependent on the vehicle speed.

15. The system according to claim 12 wherein the studs or dents are arrange in such a way that the wheel of a vehicle moving at a certain speed hits more than one stud at the same time with a time delay between hits that causes a series of acoustics impulse responses or a wide acoustics impulse response to be generated and expressed as a narrow bandwidth sound signal within the vehicle.

16. The system according to claim 12 wherein the studs or dents are arranged in such a way that when hit at the same time by a wheel of a vehicle moving at a certain speed a number of narrow bandwidth signals with different frequencies are produced, that compose the required sound within the vehicle.

17. The system according to claim 8 wherein the distance between studs or dents is constant and is relative to the sampling rate of the acoustic signal.

18. The system according to claim 8 wherein the distance between studs or dents in a narrow bandwidth signal is dependent on the main frequency of the narrow bandwidth signal.

19. The system according to claim 17 that is being adapted to generate a narrow bandwidth signal to the vehicle.

20. The system according to claim 19 comprising a number of narrow bandwidth signal generators set up over the road so as to generate respective signals having different frequencies when hit at the same time by a wheel of a moving vehicle so as to produce the required acoustical signal within the vehicle.