RMS' QuickChange Moveable Barrier has been featured in the latest issue of Safety & Security for Road Infrastructure Magazine. Below is the article in full:
SAFER SEPARATION: Zipper stitches up time savings on Sydney bus corridor - Mark Bowmer reports.
The debut on the Australian roads of an innovative lane management system is already paying dividends on one of Sydney's busiest roads. Bus commuters using the new Inner West Busway on Victoria Road are enjoying travel time savings of up to 15 minutes in the morning peak, thanks in part to the commissioning of the QuickChange Moveable Barrier System.
Nicknamed "The Zipper", the barrier system is an integral lane management tool on the Busway, which is designed to provide dedicated bus lanes in peak periods between Gladesville and the Sydney CBD on one of the city's most important public transport corridors. As part of the Busway project, a new three-lane bridge has also been constructed alongside the existing Iron Cove Bridge at Drummoyne.
The Zipper changes the lane configuration along a 1.4km length of the road corridor in the AM peak to provide a dedicated city-bound bus lane, while retaining three lanes for city-bound general traffic. By 10am the lane barrier is returned to the centre of the road, ready for the afternoon rush out of the city.
The Zipper system uses a series of concrete barriers that are picked up by a conveyor system and moved through a specially designed barrier transfer machine in an elongated S curve configuration. The system then moves the concrete barriers across one lane to create a new lane configuration.
The transfer machine used on Victoria Road has been custom designed, with fully enclosed operator cabins at either end to avoid having to turn the machine around on the roadway. Both The Zipper and the roadway are managed and operated by the NSW Roads and Traffic Authority (RTA).
Steven Issa, Manager of Planned Network Operations at the Transport Management Centre, said that The Zipper was chosen for the job on the basis of both safety and efficiency of operation. "It reduces the likelihood of a head-on crash by providing a physical separation between the carriageways, and it encourages pedestrians to cross Victoria Road at traffic signal controlled locations," he said. "And because the barrier system is fully operated from within the transfer vehicle, workers are not on the road and exposed to traffic. In fact, during transfer the vehicle is physically protected and separated from traffic in both directions by the concrete barrier. It effectively travels in a 'bubble' with traffic travelling either side."
Issa said that the moveable barrier system has already proved its worth since it came into operation in January. "We are aware of at least one instance where the barrier physically prevented a vehicle crossing onto the wrong side of the road and potentially colliding with another vehicle," he said.
In terms of efficiency, the lane transfer process takes only 15 minutes and requires only a single lane of traffic to be closed during that period. Another important performance measure that drove the selection of The Zipper was the actual operation and reliability of the lane management system itself.
Issa said that on such a busy road, it is critical that the lane transfer arrangements can be implemented each weekday without incident or system failure. The Victoria Road barrier system cannot be moved without the use of the purpose-built barrier transfer machine, but as an important safeguard, the machine can be towed to complete the lane transfer should there be a mechanical problem. To date, it has operated faultlessly.
Putting safety and operational issues to one side, the real success of the new lane management system is being measured in its contribution to the reliability and efficiency of bus operations on the Inner West Busway.
Since the Busway opened, the RTA says city-bound bus passengers travelling through Drummoyne and Rozelle are saving up to 15 minutes during the morning peak rush hour period. And although the commissioning of the Busway is primarily about improving public transport performance on the corridor, the RTA is also keenly watching to see what impact it has on general traffic flow.
The RTA says average travel times for city-bound general traffic on the corridor are still being assessed, but preliminary findings suggest they are similar or slightly improved since the Busway opened. The same applies to traffic flowing in the opposite direction.
Despite its initial success, the RTA says it has no plans to commission The Zipper system elsewhere on the Sydney network. Nevertheless, as an Australian-first application of this lane management system technology, it is certain that the RTA and other road authorities across the country will be closely watching how it performs, and what longer term impact it has on congestion management.