NEW PRINCIPLE.

Auckland Star, Volume LXX, Issue 116, 19 May 1939, Page 9

NEW PRINCIPLE.

HIGHWAY SAFEGUARDS

ROADSIDE REFLECTORS.

EFFECTIVE DEMONSTRATION,

(By Telegraph.—Press Association.)

WELLINGTON, this day

J Drivers on the Hutt Road were sur- | prised by a double line of roadside lights j over a mile or so between Ngaliauranga and Petone; tliev were not ordinary lights, carried high; they were low and brilliant; and, as a matter of fact, they were not lights at all, but were a new type of reflector which was being demonstrated to the Main Highways Board. They compare with the usual glass bull's-eye reflector as a candle ot an electric light globe, and, though there is no decision whether the Main Highways Board will adopt this remarkably effective means of improving highway safety bv so clearly outlining the roadway, the board was very ■ much impressed. The reflector lenses (three are used one above the other) look like gla"Ss, but they are not. They are pressed (or, rather, die-cast) from one of the newsynthetic resins, of the family of plasticv; of which bakelite is the best known as it is used for a hundred everyday purpefces. This particular plastic is methyl methacrylate, and was developed in EnglancT" by Imperial Chemical Industries and in America by the Du Pont Company. It is very beautiful stuff, crystal clear, extremely tough, though not shatter-proof when hit hard enough, and possessing qualities which glass could possess if it were as clear as glass might theoretically be. This crystal-clear plastic, in fact, outglasses glass, and when pressed into a reflector lens, with the concave side broken into tiny cubes, is. by measurement, just 14 times as efficient as a corresponding glass lens. Road Outline and Contours. A year or so ago accounts were received in newspaper exchanges of the use of these plastic reflectors on a main highway from Detroit to Lansing, Michigan, but they seemed too good to be true. Some of them, in fact, were, for they suggested that the reflectors actually illuminated the roadway, they do not, for their purpose is to throw back to the driver the reflection from the headlights, and as they are placed at uniform spacing (100 ft) and at a standard height above the road surface (3ft) and a few feet back from the pavement edge, the road is outlined ahead, and to a distance which is astonishing. Standard headlights will light up the road surface for about 300 ft, but far ahead, up to distances of almost a mile, the crystal eyes at the roadside shine out brilliantly.

The Hutt Road was not the best location for this first trial in New Zealand, for there is not a long enough straight to demonstrate the full range of road outlining, but as far as the end of each length between bends the temporarily fixed reflectors shone back, brightly enough. to be seen through the headlamps of approaching cars.

The method of attaching the reflectors to posts or standards is neat and simple. They slip into a metal socket, also die-cast, and are locked into place with a twist. It is impossible to remove them without smashing them completely and a new lens goes back with another twist. As long as pea-rifles are in the hands of nitwits, nitwits will shoot at things like these, but short of their being shot to pieces the lens carries on, for a bullet punches a clean hole. The surface is not as hard as glass, but takes scratching, and the resin is for all practical purposes chemically inert and has an indefinite life.

The reflectors can be tinted as needed, red. green or light amber, but the clear crystal return of the headlights is used for highway line and contour marking, and the tinted lenses for various special signs (as cross road, special danger warnings, compulsory stops, etc.). Piped Light. Methyl methaerylate poee under various simpler names. Lucite is one of them, and some extrardinary uses are being found for. this synthetic resin. It is being tried, for instance, in 6urgery and dental work for "piping" light, and delivering it cold. The light source is applied to one end of a rod of Incite (or whatever else it may be called in its different forms) and passes along its length, whether straight or bent, and pours out at the other, with heat rays filtered out. So clear and uniform is the material that it may displace glass for photographic and other lenses, for it can be manufactured into optical forms far more cheaply than glass, as it is simply diecast to the final finish without grinding. This has nothing to do with roadside outline reflectors, except that it suggests the extraordinary clearness and versatility of the material.