KEY POINTS:
Trucks crawling up Grafton Gully to the Southern Motorway will get priority in the next phase of Transit NZ's $70 million traffic-signalling scheme.
The agency intends switching on signal lights and vehicle-sensing equipment at five motorway on-ramps in the next fortnight in a bid to improve traffic flows and safety.
That's as well as similar "ramp signals" started up late last year at peak traffic times at five other motorway entry points.
The scheme will ultimately cover Transit's entire Auckland network north of Drury.
New signals will start regulating traffic flows next Monday at on-ramps to the Southern Motorway from Khyber Pass Rd and from St Marks Rd in Newmarket, and the week after next from Grafton Rd, Symonds St and Hobson St on Spaghetti Junction.
But the Grafton ramp will be the first to include a trucks-only inside priority lane, in which heavy vehicles from the waterfront will be allowed to bypass other traffic without having to stop at the lights.
That follows warnings from road carriers that trucks would cause serious disruption to other traffic if they had to halt at the top of a hill then go again from a standing start.
Transit intends allowing buses and vehicles with three or more occupants to share priority lanes yet to be installed on at least 10 more on-ramps, among 75 which will eventually be equipped with signal lights on its four Auckland motorways.
Transit estimates peak-period motorway speeds are about 12 per cent faster around the five sites where signals have operated since December - northbound ramps at Spaghetti Junction, Wellington St and Curran St and southbound at Takanini and Papakura.
It acknowledges that was at the cost of an average delay of about 2 1/2 minutes for traffic joining the motorway.
