A3 Hindhead Improvement
Part of our programme of improvements (value >10m)
Where was the project located?
Work took place on the A3 near Hindhead, between Hammer Lane underpass and Thursley.
Why was the scheme needed?
The old A3 Hindhead suffered from heavy congestion, particularly around the A3/A287 traffic signal controlled crossroads. Hindhead city centre was often gridlocked at peak times. The old road also ran through the Devil's Punch Bowl, impacting on an internationally prized area and designated Site of Special Scientific Interest.
*The estimated final cost for this scheme is £369 million. This figure is subject to final account closures and may result in a variation of this figure.
What work was carried out?
We completed the dual carriageway link between London and Portsmouth and created tunnels to carry traffic underneath the Devil's Punch Bowl Site of Special Scientific Interest. The new road is 6.5km (4.0 miles) long, including the 1.83km (1.14 miles) twin bored tunnels under the Devil's Punch Bowl. Construction began in January 2007 and the scheme opened to traffic in July 2011 with the opening of the tunnel.
Diagrams of the new road layouts can be found here:
Questions and Answers about the new double mini roundabout can be found here:
- Questions and Answers about the new double mini roundabout at the Hindhead Crossroads (68.5KB PDF)
- New double mini roundabout diagram (69KB PDF)
How did this benefit road users?
The project has removed a major source of congestion, particularly around the A3/A287 traffic signal controlled crossroads. It has delivered quicker, more reliable journeys on a safer road, and removed much of the previous peak time "rat-running" traffic from unsuitable country roads around Hindhead. The existing A3 around the Devil's Punch Bowl has been closed bringing considerable environmental benefits to an internationally prized area. The centre of Hindhead is freed from the daily gridlock that blighted the area, bringing benefits to road users, local residents and the environment.
Following scheme completion, we undertake a Post Opening Project Evaluation (POPE) to assess whether the scheme has achieved its anticipated outcomes. The evaluation is generally carried out at one and five years after scheme opening. The results of the POPE allow us to learn lessons and improve future scheme delivery.
Learn more about the POPE process
How do I find out more information?
If you have any queries about this project you should contact the Highways Agency Information Line by emailing email@example.com or calling 0300 123 5000.
The tunnel is 1.83km (1.14 miles) long comprising about 1.77km (1.1 miles) of bored tunnel and approximately 30 metres (98 ft) of cut and cover at either end. The maximum depth of tunnel below ground is about 65m (213 ft) at Gibbet Hill, (measured to the top of the tunnel).
The tunnel has two separate bores. Each bore includes a 7.3m (24 ft) wide 2 lane carriageway with 1.2m (3.9 ft) wide verges on each side. The verges are wide enough for emergency use by a disabled person in a wheel chair. Each bore has a maintained headroom of 5.03m (16.5 ft) together with a further clearance of 250mm (9.8 inches) to the underside of any plant suspended above the vehicle gauge as a safeguard against flapping tarpaulins and ropes.
The tunnel bores are approximately parallel and linked by pedestrian cross-passages at approximately every 100m (109 yards) throughout the tunnel. The tunnelling method used by Balfour Beatty was the Sprayed Concrete Lining method (SCL).
The tunnel alignment is in the middle of the Upper Hythe beds at the southern portal. These beds consist of silt sand with rock bands. Further north, it passes through the Upper Hythe beds where the percentage of rock starts to increase and then in the Lower Hythe beds there is rock with minor sand bands.
Questions and Answers on the operation of the tunnel and new access arrangements
Q. What is the speed limit for the tunnel?
A. The speed limit is 70 mph and there are national speed limit signs in the tunnel reminding you of this. If there is an incident in the tunnel such as a breakdown then these signs will change to display a 40 mph speed limit.
Q. Are there speed cameras in the tunnel?
A. No. The system measures your average speed between two fixed points outside the tunnel where the yellow cameras can be seen.
Q. What is the category for dangerous goods?
A. The classification code is A, there are no restrictions for carrying dangerous goods through the tunnel.
Q. How are the cats eyes displayed through the tunnel?
A. During normal operation of the tunnel, alternate LED cats eyes aredisplayed.
If two way working is introduced, all the LED cats eyes are displayed forming a solid line.
Q. Are you allowed to over take in the tunnel?
A. It is legally allowed to overtake in the tunnel, if the driver deems it safe to do so and conditions permit. The line markings comprising a 4m line and 0.5m gap are similar to those used at right turn ghost island. And a similar principle applies you may cross them if it is safe to do so. If a tunnel is in two way operation then the lane control signs ban you from using the right hand carriageway and that message is enforced by all the catseyes being illuminated as opposed to every other one in normal operation.
Q. Do you need to use dipped head lights while travelling through the tunnel?
A. The lighting has been designed so that you do not need to use dipped headlights. However you may find it helpful to turn on your side lights to light up your instrument panel
Q. How do I access the Youth Hostel
A. Leave the A3 at the Thursley Junction, If you are coming from the north then after leaving the A3 turn right at the top of the slip road then take a left after the bridge and then left again onto the Old Portsmouth Road then take the next right into Boundless Road following the sign to Boundless and YHA. If you are coming from the south then take the first left after leaving the A3 again following the sign to Boundless and YHA. At the Boundless Road/Punchbowl Lane junction follow the signs to the YHA along Punchbowl Lane.
Q. How do I access the A3 from the A287?
A. Travel to the Hindhead Crossroads as before and then either turn left from the Haslemere Road or right from the Tilford Road along the old A3, now renamed A333, to the Hazel Grove junction.
Q. I am disabled, are there any special procedures I should aware of if I am required to evacuate the tunnel for an emergency?
A. There are no special procedures since much depends on your disability. The verges of the tunnel are designed to be wide enough for wheelchair access and the kerbs are lowered at each emergency point and cross passage. If you are able to do so then in an emergency you should communicate with the tunnel control room via an emergency phone. If not then be assured you will be under surveillance and if necessary the control room will dispatch a supervisor to assist you. The telephones are equipped with a text service for those hard of hearing.
General Questions about the Scheme
Q. Is there a services tunnel between the two main bores?
A. No, we do not need to provide a separate tunnel to accommodate services.
Q. What happens if the electricity supply fails?
A. The tunnel will receive its power supplies from two power networks, one towards the north and one towards the south. So if one supply fails the other one will take over. There will be back-up power supplies, which will come into use should both supplies fail or should the supply within the tunnel fail for some reason.
Q. What happens if the ventilation fans break down?
A. Under normal weather and operating conditions, the movement of traffic itself would be sufficient to create the draft through each tunnel necessary to ventilate exhaust fumes. The ventilation system is designed to operate only when weather conditions (such as high winds) or traffic congestion means that exhaust fumes start to build up. Additionally the ventilation system is designed to operate successfully even if some of the fans break down.
Q. Will any road users be banned from the tunnel?
A. Yes, in the interest of safety, cyclists, pedestrians, equestrians and motorcycles below 50cc will be banned from the tunnel. Cyclists, pedestrians and equestrians will be provided with an alternative route across Hindhead Common and motocycles below 50cc will be diverted via Thursley and the Tilford Road.
Q. Where have similar road tunnels been built in the UK?
A. Similar tunnels constructed in the UK in recent years are at Roundhill on the A20 and at Southwick on the A27.
Q. How much earth will be excavated from the tunnels and what will you do with it?
A. Around 300,000 cubic metres of spoil gwas enerated was all used to build the highway embankments and earthbunds on the northern side of the tunnel. No spoil was taken away from the site.
Q. Will there be any settlement above the tunnel?
A. Our calculations predict that any settlement is unlikely to be noticeable; however we will monitor this during all tunnelling operations
Q. What safety features are you incorporating into the design?
A. The tunnel has:
- high quality lighting and ventilation
- continuous traffic monitoring and CCTV surveillance
- early automatic detection of vehicle breakdowns, accidents and fires
- quick appropriate information to drivers using automatic variable message signing, radio interrupt systems and loudspeakers
- well equipped emergency points with fire extinguishers, a manual call button and emergency telephones that can be used by disabled persons
- easily identifiable safe escape routes.
In addition have developed plans to:
- ensure emergency vehicles can get to the tunnel quickly
- route traffic away from the tunnel if blocked by an incident
- assess the risks from all credible hazards
- manage incidents.
These plans were developed in association with the Tunnel Design and Safety Consultative Group, which comprises representatives of emergency services, local authorities and the Environment Agency.