GB2334802A

GB2334802A - Bridge protection system

Info

Publication number: GB2334802A
Application number: GB9804090A
Authority: GB
Inventors: Bill Corbett
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-02-27
Filing date: 1998-02-27
Publication date: 1999-09-01
Anticipated expiration: 2018-02-27
Also published as: GB9804090D0; GB2334802B

Abstract

A bridge protection system for stopping a high vehicle before it reaches a bridge comprises traffic lights 2 located in front of the bridge and responsive means 10 located at a predetermined distance from the traffic lights. The responsive means (a swing arm assembly) is adapted to actuate the traffic lights to display a red traffic light in response to the passage of a vehicle having a height at or above a predetermined minimum.

Description

BRIDGE PROTECTION SYSTEM The present invention relates to a bridge protection system and, in particular, to such a system for stopping a high vehicle, such as a double decker bus, high truck or the like, before it reaches a low bridge in order to prevent it crashing into the bridge.

Various low bridge warning systems are known. For example GB 2 244 362, describes an apparatus for warning a high vehicle of a low bridge ahead and comprises a tensioned wire spanning the road in front of the bridge.

When, a high vehicle strikes the wire a warning signal is activated to warn the high vehicle driver to stop before he reaches the bridge.

US 3896414 describes a detour system wherein a high vehicle intercepting a light beam spanning the road activates a detour signal located in front of a bridge.

However, such known systems have a number of disadvantages and, in general, have tended not to be employed in practice due to their complexity and/or lack of effectiveness in stopping a high vehicle.

In particular, in the tensioned wire system described above, the wire is prone to damage by the vehicle and a vehicle mounted trigger is necessary to deflect the wire rather than drag it along once the vehicle has hit.

The light beam and the wire systems described above are prone to a high level of interference or nuisance operation from environmental factors such as birds, weather or the like.

Both known systems involve the activation of a special warning or detour signal to alert drivers to or detour drivers from a low bridge ahead.

However, in practice, many drivers do not react appropriately to such signals.

The present invention has been made from a consideration of the problems associated with providing an effective yet simple means of preventing a high vehicle from crashing into a low bridge and in order to provide a bridge protection system which overcomes one or more of the above-mentioned disadvantages with known systems. One preferred object of the present invention is to provide an improved bridge protection system which is more effective yet easier to implement than known warning systems.

A further preferred object of the invention is to provide a protection system wherein the height sensing means is more effective and less prone to damage and/or interference from external sources and environmental conditions. A further preferred object of the invention is to provide such a system which may be operated without the need to modify existing high vehicles. Some minor modifications may be required to a relatively insignificant number of vehicles such as open topped buses as described below.

Drivers of high vehicles that crash into low bridges are generally completely oblivious to the height of their vehicle at the moment of impact.

This may for example result from the driver being tired, being on a long journey and/or generally not being sufficiently alert and aware of road signs and the like. Nevertheless, it has been observed that all drivers almost invariably stop for a conventional red traffic light irrespective of their general alertness. In effect, all drivers have a sub-conscious tendency to stop at a red traffic light even where a preceding road sign indicating traffic light signals ahead has gone unnoticed. Almost all drivers have experienced travelling many miles on a journey whilst deep in thought on a pressing problem and then suddenly thinking how did I arrive here. The answer is that we can and do drive safely on an automatic sub-conscious safety code for roundabouts, pelican crossings and traffic lights.

According to a first aspect of the invention there is provided a bridge protection system for stopping a high vehicle before it reaches a bridge comprising traffic lights located in front of the bridge and responsive means located at a predetermined distance from said traffic lights, said responsive means being adapted to actuate said traffic lights to display a red traffic light in response to the passage of a vehicle having a height at or above a predetermined minimum. Thus, in accordance with the invention, a red traffic light comes on only when a high vehicle is approaching the bridge.

The driver of the vehicle will obey the traffic lights and will have already done so several times on his journey. He is not stopping for the bridge but is stopping for the red traffic light.

The traffic lights comprise conventional traffic lights as used in conventional traffic control systems and may vary slightly from country to country depending on the type commonly used or the national standard in a particular country. For example, in the United Kingdom, the national standard traffic light comprises red, amber and green lights. Preferably, the traffic lights display a continuous green traffic light until actuated by the responsive means. Preferably, an amber light is displayed for a short period, typically about two seconds, upon actuation by the responsive means before the red light is displayed. Thus, preferably the responsive means is adapted to actuate said traffic lights to change from green to red and more preferably to change from green to amber to red in response to the passage of said vehicle. Preferably, a continuous red light is displayed for a predetermined time or until the bridge protection system is reset. In other countries the national standard traffic light system of that country should be used.

Preferably, the green light is switched off at the same time as the red or amber light is activated. Preferably, the predetermined time for which the red light is displayed is relatively long, for example 3 to 5 minutes, typically 4 minutes, in order to draw the driver's attention to the low bridge. A suitable sign may be located adjacent the traffic lights to notify or warn the driver that the red traffic light indicates a high vehicle approaching a low bridge.

Preferably, the responsive means comprises a mechanical means adapted to be contacted by a high vehicle, preferably such mechanical means being adapted to move in response to such contact, such movement thereby actuating said traffic lights, for example by actuating an appropriate relay or switch. Preferably, the responsive means comprises a swingable arm extending at least partway across the path of an oncoming vehicle such that impact of a high vehicle with said arm causes the arm to swing or pivot towards a position substantially parallel to the roadway. Preferably, the arm is pivotally mounted on a mounting post typically located adjacent the road.

The relative height of the arm from the road surface determines the height of a vehicle which will actuate the traffic lights. Lower vehicles below the height of the arm will not actuate the traffic lights and traffic flow will continue through the green traffic light. The height of the arm may be adjustable, for example by mounting the arm on a telescopic post, and the predetermined minimum may be selected according to the clearance height of the bridge to be protected.

The predetermined distance between the traffic lights and the responsive means may be chosen as desired and typically is sufficient for the high vehicle to come to a normal controlled stop at the traffic lights dependent on the average speed of such vehicles on the road section leading to the bridge.

According to a second aspect of the invention there is provided a bridge protection system for stopping a high vehicle before it reaches a bridge comprising responsive means located at a predetermined distance from said bridge, said responsive means being adapted to actuate a stop traffic light signal adjacent said bridge in response to the passage of a vehicle having a height at or above a predetermined minimum wherein said responsive means comprises a swing arm mounted on a support to extend at least partly across the path of such vehicle, the swing arm being movable to a position clear of the vehicle when struck by the vehicle.

Preferably, the responsive means is as described above. Preferably, features of the second aspect of the invention are as described above for the first aspect of the invention.

Preferably, the responsive means includes an electrical relay.

It will be appreciated that a system of the invention may be used on each side of a bridge.

In use, the high vehicle will stop at the traffic lights, typically only a few feet from the bridge, and the driver may then be alerted by an appropriately located danger sign and start to alter his route accordingly. If the distance between the bridge and responsive means is sufficient, low vehicles may be stopped by the traffic lights due to a high vehicle behind. In this case the drivers of such low vehicles may alert the high vehicle driver.

Preferably, after a suitable time, typically 4 minutes, the traffic lights would return to a permanent green light until the sequence is re-activated by another high vehicle.

It will be seen that with a system of the invention, the high vehicle is brought to a halt near the bridge. Even if the high vehicle ignores danger signs and proceeds when the traffic lights return to green, any impact with the bridge will be minimal due to the low speed of the high vehicle at that stage.

It is noted that the use of pelican crossing lights throughout the country has made the driving public accept a permanent green traffic light, sometimes for several hours, until activated.

The invention will now be described further by way of example only and with reference to the accompanying schematic drawing which shows a system of the invention in use.

Referring to the drawing, a system according to one embodiment of the invention comprises a conventional traffic light unit 2 located in front of a bridge 4 which crosses a road 6. A high vehicle 8 is shown approaching the bridge 4. At a particular distance from the traffic light unit 2 is positioned a mechanical swing arm assembly 10.

A suitable warning notice 12 is positioned near the traffic light unit and displays suitable text to warn drivers that a red traffic light indicates a high vehicle approaching a low bridge.

The traffic light unit 2 is located in front of an relatively near the bridge 4, typically at a distance of about one metre from the bridge. The unit 2 comprises a conventional traffic light box 14 mounted on a post 16, and is capable of displaying green, amber and red lights.

The mechanical swing arm assembly 10 comprises a support 18 and a swing arm 20 mounted on the support. The swing arm 20 may have a rubber faced spring loaded contact surface particularly on the front of the arm. The arm swings or pivots about the support 18 so that when extended across the road 6 it is contacted by the high vehicle 8. The height of the extended portion of the arm may be adjustable as aforesaid to correspond with the height of vehicle required to contact the arm. In use, when the arm is struck by a high vehicle it swings about the support 18 to assume a position clear of the road 6, typically substantially in the longitudinal direction of the road 6.

The assembly shown in the figure is a vandal proof version wherein the support has a laterally extending section 22 to which the arm is connected.

The arm 20 extends downwardly from the free end of the extended section 22 and then transversely over the road 6 so that the level of the contact portion of the arm is lower than the level of connection between the arm and the support. Such an arrangement deters vandals.

It will be appreciated that any suitable assembly arrangement may be used, for example a simple arrangement wherein the arm extends directly horizontally from the free end of an upright support post.

A suitable electrical relay is provided on the assembly 10, preferably with an auto reset and time delay. For example, a one-shot electrical switch with time reset contacts may be used. In use, a 20 ton or more vehicle travelling at 30 to 40 mph has considerable impact force and the arm can be held firmly, unaffected by high winds, birds or the like. Therefore, with this system there would be no nuisance operation. Preferably, the arm comprises a rigid metal arm, with a protective spring loaded contact arm surface as previously described.

So that the invention may be used with open topped double deck buses, such buses e.g. tourist buses, may be provided with a secure metal contact bar fitted at the front of the upper deck, typically at a height of 6.5 feet from the upper deck floor. Such an arrangement would protect upper deck passengers from contact with the swing arm. However, it will be appreciated that the number of such vehicles which require minor modification is insignificant compared with the number of high vehicles which do not require any modification.

A main feature of the system of the first aspect of the invention is that it provides a definite "stop" arrangement for high vehicles approaching a low bridge. Stopping for red traffic lights is an automatic action for 99.99% of all drivers and in the system of the invention it is used simply to stop the high vehicle. The driver thinks he has stopped for a red traffic light, not for the bridge. Typically, the system then allow 4 minutes for the driver to be alerted to the low bridge.

Thus, a principal feature of the first aspect of the invention and preferably of the second aspect of the invention is that the driver will stop for the red traffic light irrespective of any warning of a low bridge condition i.e. even when unaware that a low bridge lies ahead. Known systems where a special low bridge warning sign is actuated by a high vehicle do not achieve such an effective response or tend to be ignored.

The reader's attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

CLAIMS 1. A bridge protection system for stopping a high vehicle before it reaches a bridge comprising traffic lights located in front of the bridge and responsive means located at a predetermined distance from said traffic lights, said responsive means being adapted to actuate said traffic lights to display a red traffic light in response to the passage of a vehicle having a height at or above a predetermined minimum.
2. A bridge protection system as claimed in claim 1, wherein the traffic lights display a continuous green traffic light until actuated by the responsive means.
3. A bridge protection system as claimed in any preceding claim, wherein an amber light is displayed for a short period upon actuation by the responsive means before the red light is displayed.
4. A bridge protection system as claimed in any preceding claim, wherein the responsive means is adapted to actuate said traffic lights to change from green to red or to change from green to amber to red in response to the passage of said vehicle.
5. A bridge protection system as claimed in any preceding claim, wherein a continuous red light is displayed for a predetermined time or until the bridge protection system is reset.
6. A bridge protection system as claimed in any preceding claim, wherein the green light is switched off at the same time as the red or amber light is activated.
7. A bridge protection system as claimed in any preceding claim, wherein the predetermined time for which the red light is displayed is relatively long.
8. A bridge protection system as claimed in any preceding claim, wherein the responsive means comprises a mechanical means adapted to be contacted by a high vehicle, such mechanical means being adapted to move in response to such contact, such movement thereby actuating said traffic lights.
9. A bridge protection system as claimed in any preceding claim, wherein the responsive means comprises a swingable arm.
10. A bridge protection system as claimed in claim 9, wherein the arm is pivotally mounted on a mounting post.
11. A bridge protection system as claimed in claim 9 or claim 10, wherein the relative height of the arm from the road surface determines the height of a vehicle which will actuate the traffic lights.
12. A bridge protection system as claimed in any of claims 9 to 11, wherein the height of the arm is adjustable.
13. A bridge protection system for stopping a high vehicle before it reaches a bridge comprising responsive means located at a predetermined distance from said bridge, said responsive means being adapted to actuate a stop traffic from said bridge, said responsive means being adapted to actuate a stop traffic light signal adjacent said bridge in response to the passage of a vehicle having a height at or above a predetermined minimum wherein said responsive means comprises a swing arm mounted on a support to extend at least partly across the path of such vehicle, the swing arm being movable to a position clear of the vehicle when struck by the vehicle.
14. A bridge protection system according to claim 13, wherein after a suitable time, the traffic lights return to a permanent green light until the sequence is re-activated by another high vehicle.
15. A bridge protection system substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.