HAMPSHIRE drivers waiting for the big switch-on of a trail-blazing motorway traffic light experiment shouldn't hold their breath.

It's unlikely to get a green light before Easter. The Transport Research Laboratory one-year "ramp metering" trial has seen traffic lights, gantries, electronic control boxes and cameras mushroom along the M27 from Southampton to Fareham and up the M3 to Winchester.

But instead of starting by the end of the year, as announced in advance publicity, it has been put back until April. A key delay factor is the roadworks about to start on the M27 at Southampton and its M3 western link roads as we reported in the Daily Echo yesterday.

One consolation for those who fear a "lights, cameras, TOLLS!" scenario, is that the Highways Agency insists this is a totally separate experiment.

Chris Gould, the agency's project manager for tactical network control and traffic modelling, said: "Tolling is a separate issue and ramp metering has no part in that at the moment.

"Although I can't guarantee that there won't be some link in the future, at the moment we have no intention of linking the two."

The new scheme covers eight major junctions affecting tens of thousands of drivers every day, but only six will have lights - the other two are for control purposes in the experiment.

The "active" junctions will involve southbound traffic joining the M3 at junction 11, Winchester; eastbound traffic joining the M27 at junction 2 (Nursling), junction 10 (A32 Fareham), and junction 11 (Fareham and Gosport), and westbound traffic joining at junction 5 (Southampton airport) and junction 7 (Hedge End).

The switch-on will be phased from April to September next year. Mr Gould said that apart from the fact that the M27 repairs will entail replacing some sensors already buried in the road for the ramp metering, it was preferred to wait until after the anticipated roadworks congestion had cleared.

Another factor has been the late contract letting for some equipment by the Department of Transport.

As a pilot scheme for the whole country, ramp metering will operate at peak periods to stop traffic joining the motorway at key junctions until the main traffic flow is considered light enough for small groups of vehicles to join the on-slip filter lane.

Even then, drivers will have to bide their time as the main flow traffic will still have priority. The cost - certain to run into millions - has not been disclosed but is being met from central funds because of its national importance.

Phil Cragg, the resident engineer for consulting engineers Owen Williams who is overseeing the scheme, said that the aim was to make the most of existing roadspace, and to improve the traffic flow rather than hold it up.

He said: "There is no way it is going to be easy. That is why we are phasing it in, incorporating what we learn as we go." He pledged: "If it ends in tears it will be switched off. It will not be another M4 bus lane - if the results are bad then we'll go away."

And he said the installation of 16 new video cameras - linked to the new police headquarters nearing completion at Netley - were for observation not more motorist persecution.

"None of the equipment will be available for court cases. It is to see how drivers behave in reacting to the system. There will not be speed cameras or traffic light cameras, although if we find drivers are jumping red lights those can be added," he said.

Mr Cragg said there were various failsafes. "If the sliproad traffic looks like tailing back on to the interchange roundabout then we can either turn the lights to green or switch them off, while the police with full video overview can override in emergencies. But we're fairly optimistic that it will help people on their journeys, and that overall journey times will decrease."

Converted for the new archive on 25 January 2001. Some images and formatting may have been lost in the conversion.