Autoflush traffic lights.... what about bus priority?

[dwb]

http://www.brisbanetimes.com.au/queensland/autoflush-for-brisbane-traffic-20110406-1d3vr.html

Autoflush for Brisbane traffic
Tony Moore
April 6, 2011
Until today, Brisbane City Council traffic staff have had to hold down a button and "flush" traffic through congested intersection about 1500 times a month.

Lord Mayor-in waiting Graham Quirk said that was the main reason Brisbane City Council decided to change its traffic lights system, a story broken on brisbanetimes.com.au in August 2009.

It will take about 18 months and cost around $3 million to roll out the new traffic light system.

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Some month-long trials on a section of Moggill Road, one of Brisbane's most notoriously congested roads, showed travel time savings of 17 per cent.

However, Cr Quirk said he would not expect time savings of up to 20 per cent when the scheme was totally rolled out.

Traffic lights in the CBD and Fortitude Valley will be the last of the council's 850 traffic light sets to be upgraded.

What is it?

Brisbane's "new" scheme is an old, established scheme that is already used in 142 other cities in the world - including every other Australian capital city.

Currently, Brisbane traffic lights under council control use a system called BLISS - Brisbane Linked Signal System.

From today, those lights will use SCATS - the Sydney Co-ordinated Adaptive Traffic System.

An attempt to introduce a separate system (STREAMS) with the Queensland Government has been rejected because it was taking too long, with talks lasting for at least six years.

"Delays mean it would not be in place until 2014. That is just too long for us to wait," Cr Quirk said.

How does it work?

New signal control boxes - not the traffic lights themselves - will be installed at the 850 sets of traffic light intersections throughout Brisbane.

"This system will actually count cars at traffic lights. It means it will actually change the timing of the traffic lights by itself, without human intervention," Cr Quirk said.

Traffic centre staff currently had to manually hold down a button for traffic lights to 'go green' to allow waiting traffic to "flush through" congested intersections, Cr Quirk said.

"Currently we're having to flush excess traffic intersections about 1500 times a month," he said.

Cr Quirk said the council also held green lights for emergency vehicles around 500 times a month.

The system works by adjusting the lights by measuring traffic counts against a base allocation of time for traffic travelling in different directions.

"If there is a build-up of cars in one direction, it will automatically 'flush' those cars through," Cr Quirk said.

"That's the beauty of this system. It eases the congestion. It doesn't have to wait for someone to come along and humanly intervene in those signals to 'flush' the traffic."

Maintenance is cheaper, no job losses: Quirk

Cr Quirk said the cost to maintain the new system would be about $100,000, compared to $1 million with the current 20-year-old BLISS system.

"So there are cost savings for ratepayers and less frustration for motorists in Brisbane," he said.

Cr Quirk said there would be no interruption while the new scheme was rolled out.

"Most of the work will be technical work, it will be the replacement of the signal boxes," he said.

Some road works work will be done outside peak periods to replace the "computerised loops" which allow traffic counts at traffic lights.

Cr Quirk said there would not be job losses at the Traffic Congestion Unit at the Traffic Management Centre in George Street, with software replacing the manual operation of traffic signals.

Does anyone know if SCATS is able to provide bus priority such as extended greens??

[Jonno]

Ahha! The truth is revealed. They are just replacing BLISS because our roads are anything but bliss to be on!!

[#Metro]

BLISS to CRAPS 

[Golliwog]

I don't know anything specific, but here's my two cents. It depends on what hardware they have out there. If theres a bus turning lane (eg: Coopers Camp Rd) then that should be easy enough to sort out as its still just a standard loop detector. For mixed traffic I would assume you would need an extra sensor to detect something from the bus.

[longboi]

Buses had/have transponders which work with BLISS, not sure if they will work with SCATS though 

[somebody]

Buses had/have transponders which work with BLISS, not sure if they will work with SCATS though 

My emphasis.

Do they really work?

[longboi]

Buses had/have transponders which work with BLISS, not sure if they will work with SCATS though 

My emphasis.

Do they really work?

My guess is that they do work, but probably require human intervention (ala the 'flushing' mechanism) and are not a high priority for control room operators.