Signs of the times designed to calm city streets

Slow up: Motorists have a week to get used to Ponsonby Rd's new 40km/h limit. Photo / Richard Robinson.

Signs telling drivers of a reduced speed limit along Ponsonby Rd are being erected this week as others announcing roundabouts in Pt England are disappearing.

Both measures are being discussed at a conference of more than 200 traffic experts in Auckland as ways of improving the safety of roads for a wider range of users.

Auckland City is changing its signs along Ponsonby Rd after approval by the Transport Agency, as well as residents and businesses, for a speed limit reduction from 50km/h to 40km/h.

Network performance manager Karen Hay said yesterday that police would allow a phase-in period before the new limit was enforced next week, issuing warnings rather than infringement notices in the meantime.

Pt England is pioneering a different method of calming traffic speed by adding features such as new verges and planting trees in about 10km of streets to slow traffic without the help of signs.

A total of $2.6 million has been spent on the project.

In a bid to turn these into "self-explaining roads", along which drivers are given strong visual clues to what speeds are appropriate, the council has even gained the agency's approval to remove signs announcing approaches to four roundabouts on two quiet residential thoroughfares, Tippett St and Anderson Ave.

Ms Hay said the council first had to satisfy the agency, which intends introducing the concept nationally in a new roading standard for subdivisions, that the median speed on those streets had fallen to no more than 30km/h.

A Waikato University road safety psychologist involved in the Pt England trial, Associate Professor Sam Charlton, told the Local Authority Traffic Institute conference in Auckland that the median speed along Anderson St had fallen from 46km/h to 30km/h since the completion of engineering modifications in June.

He reported similar reductions in other local streets, although median speeds along the busy "collector" routes of Pt England Rd and Tripoli Rd had fallen only about 2km/h to 53km/h and 48km/h hour respectively.

Dr Charlton said that was the intended result of improving delineation between roads serving different functions.

Before the trial drivers had few visual clues to help them tell the difference between local and collector roads, and which speeds were appropriate.

As most drivers tended to spend 90 per cent of their time on "autopilot", a major aim of the trial was to produce visual obstacles in local streets, such as to interrupt their line of sight, forcing them to slow down.

Varying verge sizes also require drivers to weave around them.

Auckland City approved the trial after councillors were alarmed to learn that crash rates in the Tamaki suburbs were more than twice those of their seven other wards.

Ms Hay said there had been no road injuries in the trial streets since the new measures were introduced.