GB2216856A

GB2216856A - A device to aid drivers in estimating distance from a vehicle ahead

Info

Publication number: GB2216856A
Application number: GB8808350A
Authority: GB
Inventors: Colin Dempsey
Original assignee: Individual
Current assignee: Individual
Priority date: 1988-04-08
Filing date: 1988-04-08
Publication date: 1989-10-18
Also published as: GB8808350D0

Abstract

Vertical lines are marked on the windscreen of a vehicle to act as a datum in estimating the distance to be allowed between vehicles travelling at a given speed. By comparing the apparent width of the image of a vehicle ahead to the distance between the datum lines, the driver can assess whether he is driving too close for that speed. <IMAGE>

Description

A DEVICE TO AID DRIVERS IN ESTIMATING DISTANCE This invention relates to a device to aid vehicle drivers in the estimation of distance, especially distance from a vehicle which they are following and from which they should maintain a 'safe distance' according to recommendations in the Highway Code.

Vehicle drivers need to maintain a safe distance between their own vehicle and the vehicle ahead, and this safe distance is primarily a function of speed.

Drivers may not be aware what this distance is in numerical terms, and may be unable to estimate it in practice.

There is a need for a device to aid the driver in estimating the minimum distance to be allowed between his own and a leading vehicle, so that nose-to-tail collisions, such as frequently occur on motorways and dual-carriageways, may be avoided.

This invention provides for datum lines to be incorporated in or near the driver's-line of sight, so that the vehicle ahead may be viewed 'through' the datum lines. By comparing the apparent width of the vehicle ahead with the separation of the datum lines, the driver may correctly estimate whether he is maintaining a safe distance.

As an example of an implementation of this invention, there is described below a version of the device designed to aid the driver in estimating the safe distance to be maintained for a speed of 112kph (70mph).

The accompanying drawing shows the driver's view, where figure 1 represents the appearance of a vehicle at a safe distance for the appointed speed. In the drawing, 1 is the driver's windscreen, 2 is the steering wheel, 3 is a vehicle at a safe distance appearing to fit between the datum lines on the windscreen. Figure 2 shows the situation where the driver is following too closely for the given speed, 4 representing the appearance of the vehicle ahead, this time overflowing the space between the datum lines.

It is assumed that the windscreen of the vehicle is about 60cm from the driver's eyes, that the average vehicle width is about 1.9m and that the minimum safe distance appropriate to 112kph is 96m.

A pair of lines, each about 0.5mm wide, is marked upon the surface of the vehicle windscreen, extending from top to bottom of the windscreen. The lines are approximately ahead of the driver's eyes, are parallel and appear to the driver to be in the vertical plane. They are about 1.2cm apart.

The driver maintaining the correct safe-distance behind another vehicle sees that the image of that vehicle when viewed through one eye corresponds in size to the separation of the datum lines. If the vehicle separation is reduced to less than the safe distance, the image of the vehicle ahead will appear to be bigger than the gap between the datum lines.

The driver is able to see his error and restore the correct separation.

Claims

1. A datum formed in or as part of a vehicle windscreen, being seen by the driver as two or more vertical parallel lines, evenly spaced and in or near line of sight when he is looking at vehicles ahead, such that the separation between the lines may be used as a reference in estimating the safe distance to be maintained when travelling at a given speed or speeds behind another vehicle.

2. A datum as in claim 1, but formed by being etched into or marked upon the surface of the windscreen.

3. A datum as in claim 1, but formed by being a device mounted upon or attached to the windscreen or suspended in or near the drivers line of sight.

4. A datum as in claim 1, but being formed impermanently, as by the shining of light or casting of shadow.

5. A datum as in claims 1,2,3 or 4, but being seen by the driver as a horizontal scaled line or as a grid or other pattern so designed as to aid in the visual estimation of safe distance.

6. A datum as in claims 1,4 and 5, but where the impermanent pattern of the datum may be varied in size or scale so as to be suitable for estimating distance at various speeds.