DRIVING AT NIGHT THE DAZZLE PROBLEM.
Page 9
Page 10
If you've noticed an error in this article please click here to report it so we can fix it.
How the Problem is Being Tackled by Inventors and Lamp Manufacturers, Opinions Upon a Recent Demonstration.
DRIVERS of commercial vehicles are as deeply interested as any other road users in the question of avoiding the dazzling effect produced by the modern headlamp. The driver of the average lorry sits at a materially higher level than the driver of a motorcar, but even this -increased elevation does not remove him from the area covered by a beam of light projected' by every lamp he has to meet at night.
It is very often the case that the lorries engaged on night work (and an article on the centre pages of this issue will show to what extent the roads are used at night-time for the transport of goods) are themselves equipped with poor road-illuminating media,the net effect, so far as the driver is concerned, being that, whilst he is faced by the dazzling lamps of an approaching motor vehicle, he is not sufficiently lighting up hisown side of the road to enable him to keep clear of the grass margin on his left. There has been an enormous number of -accidents to lorries at night-time, and all too frequently the explanation of the driver is that he was dazzled by the lights of an approaching car.
Good Lighting Essential for the Driver.
The problem is not an easy one to solve, because ample lighting of the way in front of one is absolutely essential at night-time, and must continue so until the roads themselves are lighted and their variations from a straight line marked out by standard lamps, but this would entail such a vast and expensive scheme of lighting as to be beyond the realm of practical polities. The motor-coach driver, sitting lower than the lorry driver, is even more likely to suffer from the effects of dazzle, because his position is nearer to the centre of a beam of light thrown by the lamps approaching him, The position, of course, is complicated by the fact that the motorcyclist and the cyclist, whose eye level is considerably lower than that of any other road user, have to be taken into consideration being, in fact, more vulnerable and more likely to swerve from the true path than the driver of a heavier vehicle, who, by the exercise of will, need not deflect his steering. . Anyone who has had any experience on the road at night-time will agree that it is a very unwise proceeding to switch off one's headlights. The vision of the driver is instantry disturbed by the sudden plunge from ample light to either no light or to the small amount thrown by side lamps, and, with the roadway behind an approaching car thrown into dense obscurity, the risk of running into a cyclist or vehicle following behind the approaching car (perhaps overlapping or attempting to overtake)
is extremely great. We are convinced that of the alternatives of switching out one's lights and of asking the-driver of an approaching vehicle to face the dazzle therefrom, the latter is the safer and better, and it is extraordinary how very few motorists have grasped the usefulness of the expedient of closing one eye when approaching a powerful light and of opening it instantly the dazzle area has been passed. Many minds have been concentrating upon the need and the problem of avoiding dazzle whilst retaining sufficient illumination for safe driving. The matter has, of course, come up for attention on the part of the Ministry of Transport, and, with great wisdom, the making of regulations in the matter has been withheld until there is some prospect of obtaining a satisfactory means of restricting dazzle. The much better course 'has been adopted of encouraging inventors and of stimulating invention, and in this respect the work of the Royal Automobile Club has been of extraordinary value. The Club has set out to promote the design of antidazzle devices and to encourage their use by motor drivers. The first step taken by the Club was the devising of a method of measuring dazzle, the standard disc which was produced by Mr. H. H.
Gregory, the head of the Club's technical department, having been adopted in the recommendations of the Departmental Committee of the Ministry of Transport on Lights on Vehicles.
The Valuable Work of the R.A.C.
A standardized test for • anti-dazzle lamps and devices on competitive lines has been in use now for some years, and when one examines the certificates that have been issued by the Club one realizes how wide has been the field covered by invention aiming at the prevention of dazzle.
A still further valuable move has been made by the Club, which, on Tuesday last, held a demonstration in Richmond Park, by permission of the Home Office, of no fewer than 42 different devices entered for the demonstration by their inventors or manufacturers. Of these, 18 had already been submitted for official trials by the Club, certificates in respect thereof being issued. The others were devices which had more recently been developed, and opportunity had not served for submitting them to official tests.
t The course adopted in the demonstration was, first of all, to show along the straight stretch of road at the top of what used to be known many years ago as the test hill, a Iciain of normal lamps with parabolic reflectors illuminating, at a distance of about 260 ft. from the.vehicle upon which they were mounted,. the standard disc, whilst beside the vehicle was the standard disc, illuminated by a small bulb lamp to about the degree of illumination effected by the lamps of a vehicle approaching from the opposite direction and situated, again, about 260 ft. away. This served to demonstrate the -usefulness of the disc and it also-formed. a standard by which the anti-dazzle devices subsequently shown could be judged. Drawn up at intervals across a grass sward were the whole of the cars with the competing devices, and one was able to compare, first of all, the area illuminated by the lamps of each vehicle and then, by turning towards, aP-, preaching and li.ralking through the beam, to judge the degree to which the glare had been reduced. Some of the devices were extremely good an their effects. In 'some, however, the intensity of the beam was made to suffer,-and one or two, we thought,. did not afford what one might describe as a fair driving light„ but a sufficiently accurate comparison between one lamp and another could not be obtained in the circumstances of the test, and we think that the best way of accurately comparing one device with another is to examine the figures which were published by the Royal Automobile Club last November in tabular form. These figures gave the ranges and widths of the beam at various heights and the distance from the lamp' at which the dazzle effect ceased. We would recommend, therefore, a study of those figures by anyone who wishes to go closely into comparisons.
Our own general impression of the demonstration was that there were at least three dozen devices on the market which materially mitigate the drizzle nuiss nee.
The 'demonstration was continued so that the lighting effect could he observed when each vehicle rose over the brow of a hill, rounded bends, and travelled along an undulating road, thus concluding the trial Tarried out by the Club, and one came away from the demonstration feeling satisfied that in the course of a few years, considerable progress has been made towards what—because of the large number of -vehicles now on the road—was beeomiliga very great difficulty.