ROTARY TRAFFIC ISLAND

Press, Volume XCII, Issue 27750, 30 August 1955, Page 8

ROTARY TRAFFIC ISLAND

“ Riccarton Scheme Warranted ”

VIEWS OF TRANSPORT COMMISSIONER

The Riccarton Borough Council’s proposal for a rotary traffic island at the intersection of Deans avenue and Riccarton road, which is not favoured by the Christchurch City Council, has been commended by the Commissioner of Transport (Mr H. B. Smith). Advice was received at a meeting of the borough council last evening that the City Council’s traffic committee did not favour the proposal, and that its view had been endorsed by the council.

A roundabout was warranted, said Mr Smith in his report, because of the delays and accident record at the intersection. It would be the most efficient means of handling the traffic movements at the intersection, and he had designed a roundabout that would cope with future estimated traffic flow.

Mr Smith said he considered that at the intersection, where turning traffic was fairly heavy and pedestrian traffic small, a rotary island was the best treatment practicable. The area of the intersection was large, and that would make the construction of the island simple. “It would be possible to handle this heavy traffic with traffic signals, but the cycle traffic from Hagley Park, the turning movements, and the large intersection area would combine to make the required installation complicated and expensive,” Mr Smith said. "The traffic light cycle would have to be very long, and this would result in long delays to motorists. English research has shown that there is more fuel wastage and wear and tear on vehicles at traffic signals than at rotary islands in similar situations.

Disadvantages of Stop Signs Another alternative, the use of stop signs as now in force, had disadvantages. They were at present causing long delays at peak hours, delays that would become greater as traffic increased. The additional right-turning traffic from Blenheim road would make the position degenerate rapidly and require a pointsman at peak hours The stop signs did not affect cycle traffic from Hagley Park, and there had been a number of serious accidents between cyclists and motorvehicles at the intersection in the last two or three years.

Mr Smith said the island he had designed would handle more than 2000 vehicles an hour, including cyclists, without difficulty. The present traffic peak was about 1300 vehicles an hour. The speed of traffic going round the centre island would normally be about 12 miles an hour, but when not slowed down by traffic turning the right from Riccarton avenue to Riccarton road it would negotiate the islands at an average speed of about 22 miles an hour, and the reverse flow would travel at 18 miles an hour.

Well-laid-out islands with well-kept lawns or flower plots were more attractive than a big intersection area, all sealed, said Mr Smith. That must be set against the loss of a very small corner of Hagley Park, including one of the bordering trees. It would be necessary to move three power poles, realign the fence of the park without moving the gates, instal new kerbing round the islands and on three corners of the intersection, and reform the road surface outside the park gates. “This cost must be balanced against the cost of installing traffic signals, employing a pointsman at peak times, or suffering a succession of long delays and injury accidents,” said Mr Smith.