Images of a new safety system that will help to keep the Dartford Crossing operating safely following the removal of payment barriers have been published today by the Highways Agency.
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.
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.
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.