Victoria’s Latrobe City Council has successfully pioneered the Australian development and use of a testing procedure for assessing road signs and their retroflectivity.
Council’s Senior Manager Infrastructure Operations, Stephen Howe, said road signs are an essential part of a community’s transport infrastructure.
“They guide, inform, warn and control road and pedestrian traffic, helping to maximise safety,” he said.
“Unless they are correctly maintained, signs can fade to the point where they cease to serve their purpose.”
The night time luminance of a sign is measured by a scientific property of the sign sheeting known as retroflectivity. This can diminish and the sign can become virtually invisible at night, even though it looks perfectly functional by day.
In Australia, only the initial manufacture and installation of road signs is covered by industry standards, with no guides as to when signs in service should be replaced.
Stephen Howe said in the past, Latrobe Council would only assess a sign’s day time suitability, against factors such as traffic accident damage, rust, grime or graffiti.
The few documented approaches to night time testing were simplistic and subjective.
“This was odd, as sophisticated and scientific methods existed in Australia for testing road pavement markers and edge delineators, but not for signs,” Stephen Howe said. “We therefore set out to find and implement a practical way of assessing road signs for their night time performance during the day.”
Council is now using a portable retroflectometer, along with a GPS data logger and a laser range finder to conduct scientific testing in daylight.
“The mobile GPS unit allows us to record where signs are and log data against each sign,” he said.
“The laser range finder enables officers to measure the distance between themselves and a sign without having to get out of the car and physically measure it.
“This information is then used to compare results against appropriate visibility and legibility standards so signs are replaced only when needed.”
The system was implemented during the 2005/2006 summer.
It builds on the latest complex research and testing from around the world, as well as established methods used by Australian traffic engineers.
“As a result of this technology, Council is improving the safety of its road network, particularly for older drivers, who have been shown from research to need an average of three to four times as much reflected light as other drivers in order to drive safely,” Stephen Howe said.
For further information contact Stephen Howe on (03) 5128 5470.
