Plans to install traffic lights on some Perth freeway on-ramps as part of a trial to ease peak-hour congestion have become bogged down in a stoush over national transport regulations.
The introduction of ramp signals - or managed motorways, as they are known in some countries - is part of a $128.5 million project that was to be funded jointly by the Federal and State governments.
But Federal Infrastructure and Transport Minister Anthony Albanese says the funding is conditional on WA signing up to the establishment of single national jurisdictions for heavy vehicles, interstate rail operations and maritime regulations.
WA Transport Minister Troy Buswell says the money should be released because freeway management "has absolutely nothing to do with national transport regulation".
Ramp signals, widely used in North America, Europe and Japan, are activated during peak periods to control the flow of traffic entering a freeway.
They are installed well down from the ramp entrance to allow the ramps to be used as "temporary storage" for excess vehicles. Vehicles are released - perhaps as few as one or two at a time - as freeway conditions allow.
Supporters believe delays on the ramps are outweighed by gains on the freeway. When introduced in Auckland, ramp signals improved freeway car speeds by 15 per cent.
The ramp signals plan is one of four projects linked by the Commonwealth to an agreement with the States over national regulations. The others are in Sydney, Melbourne and Brisbane.
Mr Buswell said that WA had signed the rail and maritime agreements but was still in negotiation over the heavy vehicle regulations because of local industry concern.
But a spokeswoman for Mr Albanese said the changes were designed to ensure a "nationally consistent approach to transport regulation" to improve safety, productivity and simplify compliance.
She said the move would reduce transport regulators operating across Australia from 23 to three.
The national heavy vehicle regulator will begin operating on January 21 for all vehicles over 4.5 tonnes.
Based in Brisbane, it will initially administer the national heavy vehicle accreditation scheme and performance-based standards.Once all States have agreed, it will eventually administer one set of national laws for heavy vehicles.