With the number of registered vehicles at a high and increasing level, pollution, particularly within urban environments, is of great concern. In an attempt to reduce the levels of emissions of harmful gases from vehicles a number of schemes have been proposed.

One of the most viable of these is to reduce the number of vehicles on the road by the imposition of road use related charges.

At present a series of fixed costs are incurred irrespective of the usage of a vehicle. These include purchase of the vehicle, its garaging, road tax and insurance. These costs are significant and determine that frequent use of the vehicle is required to justify the user's investment. In addition to the above fixed costs the vehicle user also incurs the costs of fuelling his vehicle. However, at the present time these costs are comparatively low and they do not present a significant deterrent to use of the vehicle.

As a result vehicle usage on the road network currently runs at a high level.

If vehicle use is to be moderated road use related costs should be increased. The most widely accepted method to achieve this is through the levying of time or distance based charges. A large number of methods of levying these charges have previously been proposed but often the costs of implementation and enforcement of these methods have been restrictive.

Thus, the present invention seeks to provide a method and system of charging for road use that is

able to be implemented simply and cost-effectively and thus in a profitable manner.

Accordingly, the present invention provides a method of charging for vehicle usage comprising the steps of: providing a vehicle usage permit having a plurality of irreversibly activatable validity sections, each section corresponding to a given period of validity activating the relevant section of the permit upon use of the vehicle during a particular validity period; displaying the permit in the vehicle to enable the activation status of a validity section to be checked ; inspecting the permit upon surrender thereof in order to determine the number of activated and/or non-activated sections; and determining a debit or credit due against the permit dependent on the number of activated and/or non- activated sections.

In this way, the user is charged in relation to the amount of use he makes of the vehicle. Light use is rewarded and heavy use penalised, thereby discouraging unnecessary journeys.

Preferably, the activation status of the validity sections is checked by human observers or by photographic/video surveillance techniques.

Thus, correct usage of the permit by drivers can be enforced either simply by observation, for example by police or traffic wardens (much like the current road tax system) or by more complex automated surveillance (like that used for the London congestion charge).

Typically the inspection and determination steps are performed manually or by automated machine

inspection, again allowing the method to be implemented in a simple or more complex form best suited to the circumstances.

In a first embodiment, the permit comprises a first sheet marked to indicate the plurality of the validity sections and a second sheet disposed adjacent the first sheet and having a plurality of irreversibly detachable portions each corresponding to and overlying a validity section of the first sheet, wherein the first and second sheets are of a colour or tone such that the appearance of a validity section is altered upon removal of the corresponding detachable portion.

Thus, the first sheet is preferably formed in a first colour and the second sheet is formed in a different colour wherein removal of a detachable portion reveals the validity section of the first colour.

Furthermore, the first sheet may be opaque and the second sheet transparent but coloured, thereby altering the colour of a validity section viewed therethrough.

Conveniently, the permit may be circular and the validity sections arranged around the periphery.

The detachable portions may project beyond a periphery of the first sheet to facilitate gripping and removing them.

For efficiency in the use of materials, validity sections may be provided on both surfaces of the first sheet and a third sheet is provided adjacent the first sheet, the third sheet having a plurality of

irreversibly detachable portions each corresponding to and overlying a validity section on the first sheet, wherein the first and third sheets are of a colour or tone such that an appearance of a validity section is altered upon removal of a corresponding detachable portion.

In another embodiment, the permit comprises a sheet folded concertina-style and sealing means operable to retain the sheet in a folded configuration, wherein the sealing means is irreversibly breakable to allow individual folded portions of the sheet to be opened out to display and thereby to activate a validity section.

In one variation, the sheet is folded in a staggered format and the sealing means comprises a tape extending across the staggered fold lines.

In another embodiment, the permit comprises a booklet having a plurality of pages joined at a spine, wherein one face of each page represents a validity section, the permit further comprising an irreversibly detachable portion obscuring at least part of each validity section.

In a further embodiment, the permit comprises a booklet having a plurality of pages joined at a spine wherein one face of each page represents a validity section, the permit further comprising irreversibly breakable sealing means retaining each page in a closed condition against a neighbouring page.

In a still further embodiment, the permit comprises a sheet divided into a plurality of areas representing validity sections and a plurality of markers attachable to the sheet to activate a validity

section, wherein the markers are attachable in such a way as to prevent subsequent removal without leaving evidence of such removal.

In a still further embodiment, the permit comprises a sheet which is at least partially transparent and divided into a plurality of areas each representing a validity section, and a plurality of removable markers affixed in at least some of the validity sections, the permit further comprising visible indicators intersecting the markers which are disrupted upon removal of a marker.

In a further aspect the present invention also provides a system of charging for vehicle usage comprising a vehicle usage permit having a plurality of irreversibly activatable validity sections, each section corresponding to a given period of validity ; means to enable checking of the activation status of a validity section during the corresponding validity period, means for determining the number of activated and/or non-activated sections of the permit upon surrender thereof ; and means for determining a debit or credit to be issued against the permit.

Preferably, the means for checking the activation status of a validity section comprises human observers or photographic/video surveillance means.

Preferably, the means for determining comprises an automated system operable to detect the number of activated and/or non-activated sections and to calculate the debit or credit due.

In a further embodiment, a permit for future use may be preactivated for a particular time period or date in an identifiable way when purchased. A

financial discount may be provided for the preactivated permit (in respect of the predetermined time period, or date) with the object of encouraging compliance with the system. A preactivated permit may only be valid for the time period or date specified when it is purchased. The permit is preferably a daily permit. The features of this embodiment may equally be employed in the other embodiments and arrangements described herein.

Examples of vehicle usage permits for use with the present invention will now be described with reference to the accompanying drawings, in which: Figure 1 is a first embodiment of a vehicle usage permit for use with the present invention ; Figure 2 is a second embodiment of a vehicle usage permit for use with the present invention; and Figure 3 is a third embodiment of a vehicle usage permit for use with the present invention ; Figure 4 is a fourth embodiment of a vehicle usage permit for use with the present invention ; Figure 5 is a fifth embodiment of a vehicle usage permit for use with the present invention; Figure 6 is a sixth embodiment of a vehicle usage permit for use with the present invention; Figure 7 is a seventh embodiment of a vehicle usage permit for use with the present invention ; and Figure 8 is an eighth embodiment of a vehicle usage permit for use with the present invention.

The system and method of the present invention require each vehicle to carry a usage permit. Each permit has a number of sections representing discrete time periods. If a vehicle is to be used during one of these time periods, the relevant section of the permit must be visibly activated and the permit clearly displayed in the vehicle. Once the section has been activated, this is irreversible and any attempt to reverse the activation is immediately apparent upon inspection of the permit.

When all the time periods for which the permit is applicable have passed, the permit is inspected to determine the number of sections which have or have not been activated and the user is charged accordingly. For example, as explained further below, for each non-activated section, the user may receive a credit leading to a discount on a subsequent permit or a refund on the amount paid if a subsequent permit is not required.

The time based validity sections of the permit can be activated by the removal of tear-off portions from the permit, or by breaking a seal between leaves of the permit, allowing a section to be opened out for display.

Activation of the vehicle usage permit for a period of vehicle use must be clearly apparent and give a strong visual signal. Having a strong visual indication of activation improves clarity for both the user and the authorities responsible for the verification of the vehicle usage permits.

A first embodiment of the vehicle usage permit is shown in Figure 1. This vehicle usage permit has a circular format.

This first embodiment of the permit 1 comprises a first sheet 2, a second sheet 7 and a third sheet 7a, the second and third sheets 7,7a being disposed in front and behind the first sheet and thus only second sheet 7 is visible in the figure. The first sheet 2 is made from an opaque material and the second sheet 7 and the third sheet 7a are made from a transparent material.

Disposed at the centre of the permit 1 is the overall validity period of the permit 1 indicated by a statement of the current year of validity and by two week numbers which are defined using a numerical system in which the year is split into consecutively numbered weeks, from 1 to 52. These week numbers may be supplemented by the calendar dates to which they correspond.

On the first sheet 2 a number of validity sections 3 are provided around the periphery of the permit 1 which correspond to discrete periods of time for which the permit can be activated. These are represented by characters such as the initials of days as shown, or the numerals representing the dates of the days. In this example, these correspond to weekdays Monday to Friday for two consecutive weeks.

The weekdays are indicated on the first and second sheets 2,7 by their initials 6 in an upper case format, the weekdays Tuesday and Thursday being differentiated by inclusion of their respective second letters in lower case format. Characters are printed on both sides of the first sheet 2 displaying different validity details. For example, in this first embodiment the characters disposed on the first side represent weekdays of two consecutive weeks and the characters disposed on the second side (not shown) represent the weekdays of two subsequent weeks.

By disposing the second and third sheets 7,7a on either side of the first sheet 2 the characters disposed on the first sheet 2 can be obscured, completely concealed, or have their appearance altered. This may be achieved by applying a tint to the transparent sheets 7,7a. The depth and colour of tint should be chosen to produce a strong visual contrast with the first sheet. For example, using a red tinted transparent material for sheets 7,7a produces a strong contrast with a fluorescent yellow or green material used for first sheet 2.

In order to further facilitate verification of the permit 1 it is desired that the characters printed on the first sheet 2 should be of a colour that contrasts with the first sheet 2. Preferably, the colour of the characters should also contrast with the second and third sheets 7,7a. In the case of a yellow fluorescent first sheet 2 and red tinted second and third sheets 7,7a characters should preferably be printed in black.

The characters indicating the validity periods are printed on the first and second sides of the first sheet 2 as described above. In order to activate these individual validity sections, tear off portions 10 must be removed from the second or third sheets 7,7a.

These tear off portions 10 are created by subdivision of the second and third sheets 7,7a using concentric and radial dividing lines 8,9. Each of the tear off portions 10 is associated with an individual validity section 3 on the first or second side of the first sheet 2. Removal of these tear off portions 10 reveals part of the first sheet 2 beneath it, and thereby changes the appearance of the validity section 3 beneath so that it contrasts strongly with other portions which have not been activated by removal of a

portion of the second or third sheets 7,7a. For example, in Figure 1, the tear off portions 10 have been removed from six of the validity sections so that the colour of the first sheet 2 is revealed. On the remaining four validity sections 3 the colour of the overlying sheet 7,7a is visible instead.

The concentric and radial dividing lines 8,9 are perforated lines but may be formed differently. For example, the radial dividing lines may be completely cut. Furthermore, the tear off portions 10 are produced in such a way that they cannot be reattached to the permit without the reattachment being immediately obvious. Provision of perforations which are permanently altered on removal of the tear off portions would facilitate this. Alternatively the top sheets 7 and 7a may be adhered to the surface of the first sheet 2 with a tamper proof seal. Removal of the tear off portions 10 would render the seal void.

Although not shown in the figure, the tear off portions 10 may project radially beyond the periphery of the first sheet 2 so that they are easier to grasp for removal.

A second embodiment of a vehicle usage permit 11 is shown in Figure 2. The permit 11 also has a circular format and comprises a first sheet 12 and a second sheet 17, but in this case both are made from an opaque material. The second sheet 17 is located in front of the first sheet 12. Disposed on the first sheet 12 and the second sheet 17 are a number of characters representing the validity sections of the permit 11.

It is intended that activation of the permit 11 should again be by the removal of tear off portions 110 from the second sheet 17, to create a visual

contrast between the first and second sheets 12,17. In this case the second sheet 17 is opaque and so the characters disposed on the first sheet 12 are concealed. For the purposes of clarity, it is necessary to also print the characters on the second sheet 17. In order to prevent any confusion between activated and non-activated periods, on removal of a tear off portion 110 there is produced a clear visual contrast between the characters of the first sheet 12 and the characters of the second sheet 17. This is achieved by making the first and second sheets 12,17 from strongly coloured or preferably fluorescent material in contrasting colours.

The initials 16 are expressed on the first sheet 12 by printing negative images of the characters of the second sheet 17. These negative images are printed in a suitable colour such that they contrast strongly with the colour of the first sheet 12. For example, a fluorescent pink first sheet 12 with characters printed in black contrasts strongly with a black second sheet 17 with the characters printed in fluorescent yellow.

In order to create the desired tear off portions 110 the second sheet 17 is divided by concentric lines 18 and radial lines 19 which correspond to each of the validity sections expressed on the first sheet 12. The dividing lines are preferably perforated. A central circular dividing line allows the removal of a circular portion from the centre of the permit so that the overall validity of the permit is activated.

This second embodiment of the permit 11 as described above has characters disposed on only one side. However, the permit 11 may have validity sections provided on both sides, as described for the

first embodiment.

A third embodiment of a vehicle usage permit 21 is shown in Figure 3. The permit 21 has a rectangular format and comprises a first sheet 22 and a second sheet 27, both made from an opaque material. The second sheet 27 is located in front of the first sheet 22. Disposed on the first sheet 22 and the second sheet 27 are a number of characters representing the validity sections of the permit. The first sheet 22 has an indication of the expiry date 23, printed at the bottom of the permit 21, and an indication of the designated validity periods, in this case AM and PM, printed at the top of the permit 21. The permit 21 is divided into ten individual validity sections corresponding to morning periods 24 and afternoon periods 25 for the weekdays Monday to Friday. These ten individual validity periods can be activated independently corresponding to periods of vehicle use.

The weekdays are indicated by their initials 26 in an upper case format. The morning periods 24 are situated on the left hand side of the permit 21 vertically below the AM designation and the afternoon periods 25 are situated on the right hand side of the permit 21 vertically below the PM designation.

The second sheet 27 is separated by longitudinal dividing lines 28 and transverse dividing lines 29 which correspond to each of the half day periods 24,25 expressed on the first sheet 22. These dividing lines 28,29 may be perforated to facilitate the removal of portions 210 of the second sheet 27 so that the initials 26 of the weekdays may be revealed. In this way it is possible to activate a morning period 24 or an afternoon period 25 of the permit 21 corresponding to the time in which the vehicle is being used.

In this third embodiment the first sheet 22 and the second sheet 27 are produced such that they contrast with each other in a similar manner to the first and second sheets of the second embodiment.

The permit may of course be produced in other ways. For example, the characters representing the weekdays or dates may be expressed by the stamping or cutting out of material from a first opaque sheet, rather than by printing. A second opaque sheet, similarly coloured to the first sheet and located behind the first sheet, initially obscures the characters. On activation of one or more of the individual validity periods by the removal of tear off portions the characters become clearly visible. This embodiment of the present invention is particularly suited to attachment to the inside of a vehicle windscreen as activation of the permit requires the user to have access to the second, rear sheet only.

In a further alternative the characters representing the weekdays or dates may be expressed by printing in an opaque colour on a first transparent sheet. A second sheet, made from an opaque material similarly coloured to the printing on the first sheet, is located behind the first sheet, initially obscuring the characters. On activation of one or more of the individual validity periods by the removal of tear off portions the characters become clearly visible. This embodiment of the present invention is also suited to attachment to the inside of a vehicle windscreen as activation of the permit requires the user to have access to the second rear sheet only.

Figure 4 shows a fourth embodiment of a permit 31. The permit 31 comprises a sheet folded concertina-style. In this case it is folded in a

staggered configuration so that each flap 32 protrudes beyond the one above it. The flaps 32 are sealed shut, for example by a tape 33 lying across the edges of each flap 32. The tape 33 must be broken to allow a flap to be lifted up and folded out as shown by the arrow. Characters representing the period of validity are provided on the sheet within each flap so that they are only visible when the tape 33 has been broken and the flap 32 folded open. Once the tape 33 has been broken, the broken edges are clearly visible and the flaps 32 cannot be resealed without this tampering being evident upon inspection of the permit.

It will be appreciated the underside of the permit in figure 4 has a correspondingly staggered concertina format and thus can also be provided with a tape 33 and markings within the flaps representing another set of validity periods.

It will also be apparent that the concertina- style folding need not be staggered and each flap 32 may directly overlie its neighbours. In this case, for convenience the sealing tape 33 can be replaced, for example, by adhesive patches within each folded flap 32 which must be broken apart in order to open out the flap and which cannot be reattached without the tampering being evident.

Another alternative permit 41 is shown in Figure 5. This permit 41 consists of a booklet comprising a number of pages 42 joined at a spine 43. When opened up, each double page area indicates one validity period. The pages may be sealed together with adhesive patches as mentioned above which must be broken to open a page. Alternatively, a removable flyleaf 44 may be provided between adjacent pages

which obscures the markings on one page. The flyleaf 44 must be removed to clearly reveal the markings to activate that validity section. To facilitate this, the flyleaf 44 may be provided with perforations 45 close to the spine 43, which provide irreversible evidence of the activation.

Figures 6 illustrates a sixth embodiment of permit 51 which consists of a sheet 52, for example of cardboard, marked out with a calender style grid.

Each validity period is activated by affixing a sticker 53 in the appropriate section of the grid.

The adhesive provided on the stickers 53 is such that they cannot be removed once adhered. Any attempt at removal will be clearly visible by leaving tearing or roughened areas, etc.

Figure 7 illustrates a seventh embodiment of permit 61. This is similar to the calendar grid of Figure 6 but comprises a sheet 62 of transparent plastic material with stickers 63 already affixed in each validity section. A section is activated by removing the sticker 63 from that section. Re- attachment of a sticker 63 is apparent due to the strict continuity of the lines 64 intersecting the stickers, which will be disrupted upon removal o a sticker, and the difficulty in correctly re-aligning the lines 64 of any sticker 63 once it has been removed.

Figure 8 illustrates an eighth embodiment of permit 71 having validity sections 72 representing, in this example, the week-days of two consecutive weeks.

As with the first, second and third embodiments described above, the permit 72 is a two-layer construction, the upper layer having removable portions overlying each validity section 72. When

the removable portions are detached and removed, they reveal the underlying section with a strongly contrasting appearance. The permit 72 may be hingedly adhered to vehicle windscreen along one edge, allowing it to be folded back to access the front of the permit in order to detach a removable portion.

It will be appreciated that these are only some examples of possible permit configurations. Any type of permit can be used to enable the present invention if it provides a clearly visible indication of whether it has been activated for a particular period and, once activated for a given period, that activation is irreversible and any attempt to cancel the activation is readily detectable upon inspection of the permit.

It is generally preferred that each vehicle usage permit is valid for a period of between a week and a month in order to spread the road use charges across the year. Permits will be surrendered on expiry and users will be issued with a new permit for the next period. As a large number of permits will have to be produced every year, in order to make the scheme viable the permits should be manufactured in a cost effective manner. It is therefore envisaged that the opaque components of the permits should preferably be made from a cardboard type material. Cardboard can be produced in a range of thicknesses and colours, it can be printed on and cut easily and if required it can be given a wear resistant finish. Advantageously, cardboard is also recyclable. The transparent components of the permits may be manufactured from polymer materials.

Furthermore, in order to help prevent the manufacture of counterfeit vehicle usage permits, the

materials from which the permits are made may be security marked in any convenient manner.

The permit may also include a tamperproof means for attaching it to a surface on a vehicle, such as the windscreen or a side window, or the dashboard. In this way once the permit has been attached it cannot be removed without this being clearly evident.

There may be circumstances when it is advantageous to issue permits with validity periods longer or shorter than those considered above. Permits having a validity of a single day are possible, for example. These permits could be divided into hourly validation periods and would be suitable for vehicle users making infrequent visits to, in particular, an urban area.

In particularly congested environments it may be advantageous to divide the permit into peak and off- peak periods. These periods could be set by a regulatory body and have scales of charges applied to them.

The means by which these permits enable vehicle users to be charged depending upon their actual level of vehicle usage is now described.

Vehicle users purchase permits in advance of the period for which they are valid. The permit must be clearly displayed in the vehicle, e. g. in the corner of the windscreen, and if the vehicle is used in a given period the corresponding section of the permit must be activated. If the road use charging scheme is to be implemented effectively provisions must be made for the inspection of permits to ensure that they are being used correctly. It is envisaged that this

inspection may be carried out by human observation using police officers or traffic wardens or by using known photographic or video surveillance techniques.

In order to facilitate rapid and accurate inspection it is preferred that the permits be manufactured from strongly coloured, highly reflective or fluorescent materials.

Upon expiry of a permit it is surrendered, for example by returning it to a location from which permits can be purchased such as a Post Office, newsagent or travel centre or placing in an automatic permit-issuing machine. Each expired vehicle usage permit is inspected to determine the number of activated periods and/or the number of non-activated periods. If all the sections have been activated the user receives no credits. However, credits are awarded for non-activated sections. Conversely, the system may be implemented in terms of debits being made for each activated section.

This inspection may be carried out by human observation or using an automated system. Apparatus for carrying out automated inspection may consist of a machine into which a permit is fed, and which is equipped with a detector for registering those sections which have been activated and/or those sections which have not been activated. This detector may use magnetic, optical or any other convenient means in order to detect activated and/or non- activated sections.

By way of example only, the circular format of the permits may be inspected by rotation of the permit relative to a stationary detector. The concertina and booklet formats may be passed over a roller which causes activated flaps or pages to flick outwardly

thereby interrupting a light beam, while non-activated parts remain closed. The calendar grid formats may be inspected by optical detector systems.

Once the number of activated and/or non-activated sections has been established the number of credits (or debits) due to the user can be determined.

The credits may be issued to the user in the form a discount on the cost of purchasing a subsequent permit, or a refund if no subsequent permit is required. The user may be required to maintain an account with funds to pay for permits against which the credits are accorded.

Thus, if a user activates all sections of a permit no credits are received and the user effectively pays the full amount for a permit. However, if some sections are not activated credits are received thus effectively reducing the cost of the permit. In this way a user is rewarded for reduced vehicle usage and penalised for increased vehicle usage.

The cost of the permits may be an isolated charge or it may be combined with other items such as the existing road tax charge.

Thus, the present invention provides a simple and cost-effective system and method for charging for use of a vehicle. The amount paid by a user depends upon the time spent by the vehicle on the road and hence encourages drivers to moderate the use of their vehicles.

Those skilled in the art will appreciate that a number of modifications and variations may be made to the details described herein without departing from the scope of the claims.