Cycles at traffic lights

Press, 30 April 1981, Page 16

Cycles at traffic lights

Sir, — The subject of my concern is the traffic lights on the corner of Moorhouse Avenue and Colombo Street. I was cycling towards Hagley Park along Moorhouse Avenue and came to the overbridge at Colombo Street. Bicycles are not allowed over this bridge, so I waited at the lights below the bridge. I sat for a long time, watching four cycles of the lights, and never was I given the green light. Eventually I was forced to risk life and limb (mostly mine) to get through the intersection against red lights. Am I supposed to suddenly become a pedestrian when I come to this corner? Do I wait for a car to come along to activate the magnetic detector in the road? These detectors can be adjusted for cyclists. — Yours, etc., A. R. MARSHALL. April 19, 1981.

[Mr P. G. ScOular, Deputy General Manager and City Engineer, replies: “Unfortunately, cycle detection is not always easy to achieve, particularly since the advent of alloy wheels and other alloy parts. Some cycles simply do not contain sufficient magnetic material to activate the detector buried in the roadway. Some detectors can, however, be made sensitive enough to detect most bicycles but at this level of sensitivity the detector tends to pick up traffic travelling in adjacent lanes or in the opposite direction. Some have even been known to respond to electrical appliances or radios being used nearby. This introduces quite serious problems in the efficient and logical operation of the signals. At ColomboMoorhouse considerable time and effort is being put into

experimentation with cycle detection. Part of the problem lies in positioning the detectors so that the narrow cycle comes within the field of influence of the detector positions some 30 metres from the stopline. This is particularly so on the Moorhouse Avenue approaches referred to, as there is separate detection for the left turn lanes and for the combined straight through/right turn lanes. Some cyclists tend to follow the painted line separating these two lanes whes approaching the intersection. Because of the need to distinguish the two movements this is the area of the roadway in which detection is least likely. The chance of detection will be greatly increased if a path along the centre of the lane is adopted. Alternative long-term solutions are currently being investigated. In the meantime the sensitivity of the detectors has been checked with a view to improving the situation described."]