"DEVICE TO FACILITATE IMPROVED ROAD SAFETY"

This invention relates to a device intended to facilitate improved road safety by influencing driver behaviour, in particular by encouraging drivers to obey prescribed limitations on vehicle movement, for example speed limits.

Much attention has been given by legislatures in recent years to the persuasive modification of driver behaviour in the fields of blood alcohol levels and seat belt protection. However, it is generally agreed that excessive speed is at least as important a contributory element of serious motor vehicle accidents and is particularly potent when combined with alcohol or inexperience. The standard approach is the use by police of amphometers and radar devices to detect speeding infringements but it is clear that transgression remains widespread.

The present inventor considers that most drivers will, on reflection and consideration, readily admit the need for speed limits and the desirability of keeping by them, but tend when actually on the road to succumb

to pressures of time and to boredom by exceeding speed limits, and that they are prepared to do this simply because they believe that the odds of being caught are minimal so that the rare fine is simply an acceptable licence fee for multiple transgressions.

It is therefore an objective of the invention to provide apparatus whereby the driver, who in most cases is readily persuaded to law abiding behaviour, will be influenced to generally keep within prescribed limitations on vehicle movement, for example speed limits. The invention accordingly provides apparatus for mounting in a motor vehicle comprising: sensor means for monitoring indications, disposed externally of the vehicle, of a prescribed limitation on vehicle movement, and outputing a first signal representative of such an indication; information storage means; and comparison means adapted to be coupled to the sensor means to receive said first signal, to compare the prescribed limitation on vehicle movement with observed movement of the vehicle, and to store in said information storage means a record of a predetermined variation from said prescribed limitation. <

The sensor means may be adapted to read indications comprising coded data, e.g. barcodes, on the road surface, or to respond to radio transmitters at the roadside which include encoded indications of the prescribed limitation. The prescribed limitation might comprise a speed limit. The externally disposed indications may then be located where there is a change in speed limit, so that a driver may be advised of a

change of speed zone and adjust his speed accordingly, or might only be provided at the commencement or conclusion of zones in which the speed limit is other than a prescribed built-up area limit or a prescribed absolute maximum, for example 60kph or lOOkph respectively. The comparison means may be coupled to receive signals representative of the actual speed of the vehicle. Such coupling may be mechanical, driven directly from a transmission or axle line, or might be electronic, being responsive to periodic pulses triggered by rotation of a transmission element such as the gear box, an axle member or a wheel.

The invention also embraces the aforesaid apparatus mounted in a motor vehicle. The record of the predetermined variation, i.e. the infringement record, might include particulars of the. actual speed and. the duration of the infringement, and the time, date and location. Conveniently, the record might be provided in some form of sealed non-erasable format, for example in a memory chip. It is envisaged that when the owner of a motor vehicle is due to renew his motor vehicle registration or perhaps his driving licence, the _vehicle would have to be presented for official reading of the record and appropriate fines paid if renewal was to be effected.

The apparatus may further include timer means for determining the duration of a current variation from said prescribed limitation, and the predetermined variation may be a variation for at least a prescribed minimum time. Such time, during which e.g. excessive speed would not be recorded, might be in the range 20

sees to 5 minutes, preferably about 30 sees. This would allow the driver freedom to, e.g. pass other vehicles or cope with emergency situations without fear of penalty, and would also prevent undue harshness. The time should not be so great as to readily, and without inconvenience or close concentration, allow a driver to periodically briefly lower his speed to avoid penalty. There is preferably audible and/or visual warning means for indicating, within said prescribed minimum time, tha-t a current variation from said prescribed limitation will become a prescribed variation unless rectified.

In separate aspects, the invention also embraces the aforesaid apparatus mounted in a motor vehicle and is directed to a road surface having a marking which includes a machine readable encoded indication of a prescribed limitation on vehicle movement at or adjacent the location of the marking.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic diagram of the principal components of speed infringement recordal apparatus for a motor vehicle, being apparatus in accordance with a preferred embodiment of the invention; Figure 2 is a vertical sectional view of the shielded sensor means of the apparatus of Figure 1;

Figure 3 is a perspective diagrammatic view of a roadway fitted with a barcode speed indicator in ^' accordance with another aspect of the invention;

Figure 4 is a flow diagram of the interrupt program routine of the microprocessor for reading a barcode speed indication; and

Figure 5 is a flow diagram of the main program routine of the microprocessor.

The apparatus as schematically shown in Figure 1 includes a controller 10 and a reflex photoelectric sensor 12. Controller 10 is mounted at any suitable location in the vehicle and is coupled both to receive electrical signals fron sensor 12 via a serial port 15 and to monitor the electronic pulse signals generated by a transmission element of the motor car, in this case a rear wheel 14, so as to be directly indicative of the speed of the vehicle. Such pulses are typically delivered by a conductor 16 to the speedometer 18. A branch conductor 20 delivers a proportional such speed indicative signal to controller 10' via an interface circuit 21.

In motor vehicles, such as most older motor vehicles, in which a cable is employed to mechanically couple the gearbox and the speedometer, it would be necessary to include a device for converting the revolutions thus transmitted to a proportional electrical signal for the controller. Sensor 12 is provided to monitor external indications of a predetermined speed limit for the time being, viz the speed limit currently applicable on the stretch of road along which the vehicle is travelling. To this end, the sensor would typically be mounted towards the front underside of the vehicle, for example under the engine cooling fan and/or adjacent the

radiator, but may be mounted at any other convenient location, e.g. adjacent the passenger cabin floor.

A suitable sensor arrangemen.t is illustrated in Figure 2. The sensor 12, which is conveniently an infrared device and typically has a light transmission port 12a and an adjacent reflected light receiver port 12b, is supported within a tubular shield 22. Shield 22 is obliquely truncated at its lower end so as to depend further at the front 22a, which respect to the vehicle's direction of travel, and thus to maximize diversion of mud and the like away from the sensor. A venturi device, a convection fan or like means 24 is provided at the top of the shield for directing a flow of air 25 downwardly past and about sensor 12: mud or grime which is thrown up into the shield 22 is forced away by this air flow. It will be noted that tubular shield 22 is in two axial parts threadingly coupled at 26 just below the sensor to facilitate regular cleaning of the sensor's light ports 12a, 12b. In an alternative construction (not shown) , the light ports might be cleaned by a physical element such as a mylar belt moved regularly or continuously across their external surfaces.

In the present case, sensor 12 is responsive to

< barcodes on the road surface which include encoded indications of the local speed limits and of the location. The envisaged barcode arrangement 40 is depicted in Figure 3. A sequence of sharply contrasting lines or spaces 42 is applied to the road surface, the lines are straight and extend across the full width of the bitumen. A barcode would typically include four encoded sequences. In the order in which they are

encountered by the travelling vehicle these would include a characteristic opening sequence, a second sequence characteristic of the location of the speed zone, a third sequence indicative of the speed limit in the zone, and a fourth characteristic closing sequence. To prevent a vehicle avoiding the barcode by travelling around it on the gravel or grass verge 44, respective suitable barriers such as so-called armco rails 46 are typically installed to either side of the barcode marking 40.

Controller 10 is of standard physical construction, comprising a microprocessor CPU 10', suitable information storage means in the form of memory modules 11, 13 in RAM and ROM, the former including a clock and calendar, a backup battery 50 for the data memory 11, serial port 15 to receive the signals from sensor 12, input interface 21 to speedometer line 16, and an output interface 17 with protection circuits 17a and external connector 19 by which the contents of specific memory addresses may be automatically read by a regulatory authority. Controller 10 also has outputs to an audible and visual warning display 28 and to a LED display 30. These elements would typically be sited for driver observation on or adjacent the vehicle's dash board. Power for the CPU and sensor 12 would be derived from the vehicle battery and be enabled by the ignition system. Backup battery 50 is provided to maintain the infringement record when other power fails. There might also be provision as a tamperproof innovation, for backup power to be provided by the vehicle speedometer drive generator.

The operation of controller 10 and its sequence of functions is determined by a program routine in a segment of ROM memory module 13. . The principal functions are as follows:

1. Recordal of the current speed limit as determined by sensor 12.

2. Activation of.display 30 to inform the driver of that current speed limit. There might also be a special visual and/or audible indication, e.g. a chime, of a change in speed limit.

3. Continuous comparison of the vehicle's speed, based on the input at interface 21, with the currently recorded speed limit.

4. Activation of warning device 28 when the speed is in excess of the speed limit, perhaps absolutely or more probably when in excess by a small margin, e.g. 2 or 3kph.

5. Setting of a predetermined delay time after activation of the warning device 28.

6. Storage of a record of an infringement, for example in a block of EPROM memory in module 11, if the speed remains in excess of the limit, if appropriate by the inbuilt margin, for more than the predetermined delay time. An infringement subject to these parameters constitutes a predetermined infringing variation from

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the prescribed limitation comprising the currently recorded speed limit.

7. An indication at display 30 that an infringement has been recorded.

5 The record of infringement typically include an encoded recordal of the speed limit, the location of the speed zone (as determined by sensor 12 from barcode 40) , the speed of the vehicle at the conclusion of the delay time, and the date and time of the infringement. Controller 10 may include a facility to make a special memory record in EPROM if it or any part of it is disconnected or if the sensor 12 is obscured and unable to make a reading. Obscuring or ineffectiveness of the sensor might be notified to the driver at the

15._ dashboard by a special warning light that he may have a certain time in which to rectify the matter before it is recorded in memory module 11.

The apparatus further may include a vibration switch 52 adapted to output a signal, stored as a

20 special record in EPROM, if it senses sustained accelleration for a prescribed minimum period of time.

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This facility is intended to detect vehicle movement when, e.g., input interface 21 has been disabled or the apparatus has been otherwise rendered inoperative. As a

25 further anti-tamper measure, controller 10 is arranged to record particulars of any erasure or attempted erasure of the infringement record in memory module 11. When the owner of the motor vehicle comes to renew his motor vehicle registration, the vehicle would have

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to be presented for official reading of the infringement record by a suitable plug-in device co-operable with connector 19 and appropriate fines paid if renewal of the registration is to be effected. This reading would also include the disconnection, erasure or sensor obscurity record, and any record of response in the vibration switch 52, for each of which events a special penalty (e.g. similar to that for refusing a breathalyser test) might be payable. Figure 4 is a flow diagram of the interrupt program routine by which a barcode indication of speed limit is read and entered, once detected by a signal from sensor 12. This routine is entered by interrupt vector when sensor receiver port 12b is enabled and the first bit is received by serial port 15. The routine thus includes the first two of the principal functions listed above. Figure 5 is a flow diagram of the ^' main program routine, embodying the other principal functions. The "FLASH ON" instruction refers to flashing the visual component of display 28.

It is believed that the described and illustrated device would be very effective in reducing excessive speed and the <refore the incidence and seriousness of accidents since it ensures that a driver will be penalized for his transgression. The reasonable odds at present and the statistical fact of only the occasional fine for the regular transgressor will no longer apply. Police will no longer be required in large numbers in traffic branches and will able to be diverted to more socially useful tasks associated with the solving of real crimes. Equipment such as speed radar, speed

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11 cameras and amphometers would no longer be required. Speed limit ^' s could be raised where appropriate without the fear that drivers will simply-take advantage and still travel at similar margins above the new limits. it will be appreciated that the invention does not constitute any kind of speed governor and therefore in no way impedes the performance of the motor vehicle. The driver can still exceed the speed limit briefly, for example when passing or to avoid a dangerous situation, and this provision of both a grace period and a warning to the driver renders the device "user friendly". The driver is still able to travel very fast when required in an emergency. Proof of such an emergency would allow avoidance of a fine when the infringment record is read. It will be further appreciated that the invention is not limited in application to speed limits but may be applied to any prescribed limitations on vehicle movement, e.g. a red traffic light, a requirement to fully halt at a stop sign, specific movements set by arrows on the road surface, double lines, one way streets, and various no turn rules. The program may also provide for special, e.g. lower, limits applicable to a vehicle of the particular type in which it is installed. The inboard equipment may include additional facilities. For example, it may be programmed to record toll, parking or other charges of subsequent processing and payment: these may be indicated in external indications, such as barcodes in the road surface, and recorded via the sensor.