Savings on route above expectations

Press, 16 July 1983, Page 9

Savings on route above expectations

An early assessment of the Southern Arterial route’s likely benefits had been “extremely conservative,” according to a Christchurch City Council report to the National Roads Board’s road research unit. The southern route from Barrington Street to Blenheim Road, which was opened in 1981, had produced a net annual benefit of about $1.4 million. That saving was mainly in travel time and vehicle running costs. A survey of the area’s road network in 1979 was compared with the 1981 survey to produce those findings.

City Council traffic engineers produced the report with assistance from University of Canterbury researchers. After the arterial route

was opened as a link in the southern ring road system, the area road network experienced a 12 per cent increase in traffic flow. Of that, 5.4 per cent could be accounted for by a general traffic increase over the entire urban area. The remaining 6.6 per cent came either from traffic generated in the area’s network, or from traffic which diverted from outside routes. Drivers of heavy commercial vehicles were more likely to have diverted to the speedier arterial route than car drivers. Vehicle running costs for the survey network decreased about $2.7 million — or 12.4 per cent — because of the arterial’s opening. Such factors as road maintenance and capital costs were subtracted

from that figure to produce the net benefit. The Southern Arterial route cost $lO million to build. > The 1981 survey showed that Blenheim Road traffic had decreased from 15,900 to 14,200 vehicles a day after the arterial opening. Riccarton Road traffic remained static at about 18,000 vehicles a day. Less traffic was using it for long and medium distance trips. Traffic in Waimairi Road, north of its curve into the Peer Street road link had increased from 8300 to 10,200 vehicles a day. The report said that economic evaluations made during planning for the Southern Arterial had suggested much lower savings than were measured a few months after the route was opened.