DANGER SPOTS.

Auckland Star, Volume LXVII, Issue 285, 1 December 1936, Page 18

DANGER SPOTS.

NEW SYSTEM OF SIGNALS. AMERICAN EXPERIMENT. AUTOMATIC WARNINGS. A sj'stem of signals to compel reduction of speed at danger spots has been developed by an American, Mr. Charles Adler, and is to be installed at a dangerous curve near Baltimore. Mr. Adler gives the following account of it: — It comprises a traffic signal, suspended over the centre of a highway just iri advance of a curve. The signal normally displays the red indication. Aboul 70ft, in advance of the signal is an illuminated roadside sign showing the maximum safe speed for rounding the curve. Embedded in the right-hand lane ot the highway, and ad.acent to the sign, is a vehicle sound detector for the control -of the traffic signal at the curve ahead. This apparatus consists of a rectangular hollow steel unit with the top of the chamber level with the eur-

face of the road. The sound of vehicle tyres as they pass over the unit is picked up by a microphone in the interior, which converts the sound waves into electrical impulses. These imnulses are conveyed by wires to a timing mechanism, which in turn operates the signal .lights.

When a car passes the sound detector, the signal timing mcciianisni is actuated, and, after a delay of several seconds, this mechanism changes the signal indication from red, or stop, to flashing amber, or slow. The duration of this delay is equal to the number of scconds required by a vehicle to traverse the distance between the detector and the 'signal, if the car is travelling at the rate of speed specified by the illuminated warning sign.

Tf the driver is alert and voluntarily reduces the speed of his ear to the prescribed safe limit, the traffic signal at the curve will change from red to ambe:' 1 'Tore he reaches it, and thus permit him to proceed around the curve without stopping. However, should a driver fail to reduce voluntarily the speed of his car to the safe limit, lie will reach the signal before its predetermined changing time has elapsed, and he, will have to stop and wait for the signal to change.

The signal will remain red also if I'll approaching vehicle is not entirely on the right side of the road, as the wheels of the car would not pass over tlie ditector, which is placed only in the right-hand lane. The car would be stopped by the signal to prevent possible collision with cars approaching in the opposite direction.

When a line of closely following automobiles approaches the signal, and the vehicles are moving at the proper safe rate of speed, the signal will display the amber light until a gap occurs in the line. It will then revert to its normal red.

As an added safeguard, the presence of automobiles coming from the opposite direction is detected, and warning is conveyed to motorists by means of indicators which become illuminated by the passage of vehicles over the detector in the highway. In order to protect equally motorists approaching in both directions, the signals, indicators; and detectors, are installed at both entrances to the curve.

A system of this nature may be employed also at other danger zones, such as steep down-grades, school zones, road-ends, and narrow bridges, to control the speed of automobiles.