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Shouldering the burden

Highways - This month marked a watershed in UK highways when motorists in the West Midlands became the first to sample hard shoulder running. Is this the future? Mark Hansford reports.

Motorists in the West Midlands have the distinction of being the first in Britain to be able to drive on the hard shoulder during busy periods to cut congestion.

The scheme, launched on a 17km section of the M42 in September, is part of a $190M Highways Agency scheme called Active Traffic Management (ATM).

It aims to help keep the traffic moving by making the best possible use of the space on our existing motorways, rather than building more new roads. It could be a model for the future.

'It is a fifth the cost of widening this section of road, it is environmentally better as we have taken no land, and was much quicker to get up and running, ' says David Grant, head of the M42 ATM project.

The ATM stretch between junction 3A with the M40, and junction 7 with the M6, carries 140,000 vehicles per day.

Drivers using this stretch can now be directed onto the hard shoulder at times of peak congestion by electronic signs above the carriageway.

These make a 50mph speed limit sign appear above the hard shoulder. When this comes on , a maximum 50mph speed limit is applied to all lanes on the carriageway including the hard shoulder. Two weeks in, the trial is working a treat. 'We are absolutely delighted with the way the whole project is working so far, ' says Grant.

'There was an immediate effect. I was stood on a bridge on the first morning with the BBC, and they could see it.

Traffic began to slow down. It got down to 40mph and we switched on the signs. And within one or two minutes it was back up to 50mph, ' he says.

'Immediate results.' Even better ? initially at least ? it appears that fears raised over safety and particularly access for emergency services are proving unfounded.

'It appears a fairly simple operation to open a hard shoulder but years of concentrated thought and the most extensive hazard and risk assessment ever done has got us to where we are today, ' says Grant.

Safety is crucial and was designed in from the start, he adds.

'If you look at design, we looked not only at operation but maintenance as well. For example, gantries are lightweight so they can span the whole width of the road eliminating the need to work in the central reservation.

Corus provided the gantries, and they have been developed to be maintenance free for 30 years ? again eliminating the need for maintenance crews in dangerous locations. Emergency refuge areas are generally designed to be adjacent to gantries to give maintenance crews somewhere to park safely.

'And from an accident perspective we looked at our Dutch colleagues who have already done it with a 35km stretch near Arnhem. There, the experience is that the number of accidents is down 13% and the number of casualties down 19%.

And more to the point, adds Grant, 'around 5,000km of dual carriageway in the UK has no hard shoulder and people just accept that. And speeds are likely to be lower on the motorway as we will only operate hard shoulder running with a 50mph limit.

'And you ask how the emergency services get to accidents? The same way as on that 5,000km of dual carriageway. But here we can get information to drivers very quickly and can close the relevant lane to give emergency services access all the way through.' And do all motorists obey the signs? 'We have got a very good uptake and good lane discipline, ' says Grant. 'People are following signs and signals.'

This also relates to speed limits.

'Compliance with the speed limit is around 95%, which means that enforcement is not an issue for us, ' he says.

Making sure motorists obey the variable speed limits is critical to the scheme's success ? it is not all about gaining an extra lane. Slower speeds mean smoother ow, which in turn reduces congestion.

'We're very happy, ' says Grant. 'In the first week we had three breakdowns which didn't reach the refuges. All three were dealt with swiftly and in the way envisaged, ' he says, explaining that any breakdown should be picked up by 192 new xed CCTV cameras installed to enable the regional control centre to carefully monitor the scheme.

All of which means that even at this early stage, Grant is tentatively looking to the future.

'This is a pilot and we are learning lessons from it. We will be monitoring it until the end of 2008. We have very extensive 'before' data and will do very extensive 'after' data. It takes quite a while to establish a business case.

'But, it is in operation now and until our needs change, it will operate. Elements of it may even be rolled out before the end of the trial.

'ATM is a toolbox of different operational regimes. It may be that we don't employ them all at every location.

'It might be that loop detectors don't need to be at 100m intervals. It may be they could be at 200m.' The idea of expanding the pilot to include the rest of the Birmingham box has already been mooted, and Grant is quietly condent.

'It is going to be more difcult because there are some elevated sections. There are obviously funding constraints.

But it is something we are keen to look at.

'And conventionally widening those elevated sections would be extremely difcult.'

How it works

When the early signs of congestion are detected on the M42 Active Trafc Management scheme, the control centre operator and automatic system will change the signs and signals to alert road users to the conditions ahead.

The system automatically calculates the best speed to keep the traffic flowing and then this is displayed on the speed limit signals overhead.

The control centre can also open the hard shoulder as an extra running lane to reduce the impact of congestion by providing extra space for the traffic. This will help to keep the trafc owing and minimise delays.

'Theoretically a three-lane motorway reaches capacity at around 5,400 vehicles per hour, ' says Grant. Very roughly speaking, when we get to 5,000 vehicles per hour a light comes on in the control centre saying we are getting near to capacity. The variable speed limit signs are automatic, the hard shoulder is manual.' Before the hard shoulder is opened, a series of safety checks are performed. 'We do a debris sweep of the hard shoulder with a trafc ofcer and carry out visual checks. We also have sensors in the hard shoulder every 100m that detect the presence of vehicles. All of that takes place before we open it, ' says Grant.

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