Since it launched on 30 November last year, Dart Charge has already helped to speed up journeys by removing the need to stop at a barrier to pay the Dartford Crossing charge. But to get the most benefit from the changes, there needs to be a new way of identifying and managing overheight vehicles and dangerous loads before they enter the tunnel – a job until now that was carried out at the payment barriers. This is part of the wider changes which include signage on the approach to the Crossing, to give HGV drivers enough warning to get in the correct lane.
All major tunnels have rules about what substances can be taken through them and the Dartford tunnels are no exception. Vehicles carrying some of these substances may require an escort though the tunnels; some others may be prohibited altogether and need to find an alternative route. In addition, the two tunnels at the Dartford Crossing are slightly different sizes, having been opened almost 20 years apart. Vehicles more than 4.8 metres high can only use the eastern tunnel, and vehicles more than 5 metres high cannot use the tunnels at all.
The new safety system will use various detectors to identify the vehicles, signs to encourage drivers to get into the correct lane in good time, and barriers and traffic signals to control them - bringing them to a safe stop and turning them around if necessary. Lanes at the side of the main carriageway will enable this to be done quickly and efficiently, minimising delays for other drivers.
The system has been extensively tested over the last six months at a disused airfield using vehicles from a local haulage company.
Highways Agency Project Director Nigel Gray said:
> With Dart Charge, drivers no longer stop at a barrier to pay the crossing charge, speeding up journeys and reducing congestion. But the barriers are also the point at which we have identified and managed dangerous loads and oversized vehicles – so now we need a new approach. This system has been extensively tested and will be able to do the job effectively, and without requiring every driver to stop. It is a big part of fully realising the benefits that Dart Charge is already bringing.
Construction of the new system of traffic signals and barriers on the northbound carriageway will begin in late January and is due to be completed by early April.
While the new system is installed we will continue to use the re-configured booths and barriers to manage northbound over-sized and dangerous goods vehicles. Journey time improvements following the introduction of Dart Charge will be improved further once the old barriers are fully removed and the new system in place, however there has still been an improvement (averaging around four minute quicker journeys northbound compared to nine minutes southbound).
Connect Plus, the Highways Agency’s main service provider for the whole M25, are carrying out construction work associated with the project.
Erwan Huerre, Transition Director for Connect Plus, said:
Our construction work will be ongoing whilst we build the new tunnel safety system, consisting of new signals and barriers. It is important to remember that these barriers will be in the ‘open’ position most of the time, and will only need to be used when a non-compliant vehicle is detected. To maximize the effectiveness of the new system, drivers – in particular HGV drivers – are encouraged to familiarize themselves with the future layout.
To date, over-sized and dangerous goods vehicles have been managed by the barriers at the old payment booths. However, with the introduction of Dart Charge and the ongoing removal of the payment booths a new method of stopping these vehicles from entering the tunnels is needed.
The new system will detect whether a vehicle is too tall, wide or long to enter the tunnels or whether it is carrying hazardous goods that mean it cannot enter the tunnels or needs to be escorted. These will trigger a system of traffic signals and barriers that will stop the vehicle.
The new system has been designed to ensure that when a vehicle needs to be diverted away from the tunnels it is done in a way that causes the minimum disruption and delay to all drivers using the northbound carriageway.
Turning back any vehicle will cause some delay to other road users but is essential for the safety of all road users. The Highways Agency wants to ensure this happens as rarely as possible and is working with partners such as the Freight Transport Association, Road Haulage Association and other organisations, including those representing overseas haulage companies, to promote the tunnel height and other restrictions at Dartford to ensure drivers comply with them.
The Highways Agency has published guidance for these drivers, and this can be found on their website.
Advice to drivers of tall vehicles
If you are driving a tall vehicle, you need to ensure you get in the correct lane as soon as possible after junction 2 to avoid being in the wrong lane. New signs will inform you which lane you should choose.
The northbound carriageway now divides just after the junction 1a exit slip road, with the two inside lanes (left-hand lanes) dedicated to the west tunnel and two outside lanes (right-hand lanes) dedicated to the east tunnel. Vehicles joining at junction 1a can only access the two inside lanes and use the west tunnel.
Tunnel height restrictions are 4.8m for the west tunnel and 5.0m for the east tunnel. Vehicles joining at junction 1a can only access the two inside lanes and use the west tunnel, and therefore vehicles over 4.8m in height are prohibited from using the slip road and should, if under 5m, use junction 1b.
Drivers who fail to use the correct lanes will be in violation of traffic regulations and could face enforcement action from the DVSA – potentially a fine and points on their licence.
Advice to drivers carrying hazardous materials
Arrangements for drivers with hazardous loads are essentially unchanged – drivers should continue to exit at junction 1a and follow signage to the vehicle marshalling area where they can be checked and escorted through the Crossing. The safety system will identify, stop and turn around drivers who fail to do this.
Members of the public should contact the Highways Agency Information Line on 0300 123 5000.
Journalists should contact the Highways Agency press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.