Variable speed limit
Speed sign trial for M4
By ANTHONY PETERSON
MOTORISTS on the M4 will today be part of an innovative trial aimed at improving the flow of peak hour traffic and enhancing fuel efficiency.
Utilising a computerised system, speed limits will automatically change based on the volume of traffic.
The speed limit at any one location generally will change by 10km at a time and the maximum increment is 20km.
The Roads and Traffic Authority said a reduction from 90km to 60km, which is the minimum, would not happen in one step.
It is hoped by altering the speed limit the number of rear-end accidents will be reduced and millions of dollars saved in fuel consumption.
RTA communications director Paul Willoughby said the computer system is the first of its kind in Australia.
Hundreds of sensors under the road detect the number of cars passing. That information is fed to a computer for assessment of the suitable speed.
Necessary adjustments can be made at three minute intervals.
"If the trial is successful the new system should save motorists money in reduced fuel consumption and accident costs," Mr Willoughby said.
The three month trial will test and fine tune the system's ability to improve traffic flow during peak periods.
The section of M4 being used is between Concord and the tollgates at Silverwater.
Variable speed limit signs were installed in 1999.
The RTA's Transport Management Centre at Eveleigh has manually altered the signs when there a traffic incident occurred.
An estimated 5200 vehicles per hour during peak times travel on the M4. The maximum capacity is 6000 cars an hour over three lanes. The maximum speed limit is 90km.
The new system will respond to any traffic congestion and the signs will flash to alert drivers of impending changes.
If successful the system will be considered for use on other motorways, Mr Willoughby said.
The RTA announcement came as Premier Bob Carr said an extension of the M4 joining the City-West link was a long way from being a done deal.
Reports claimed the government had fielded several private sector offers to complete Sydney's "missing link".
"I haven't seen a detailed proposal from the Minister (Carl Scully). It's going to take a bit more time," Mr Carr said.
You know, somebody actually complimented me on my driving today. They left a little note on the windscreen. It said, 'Parking Fine.'So that was nice.