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Hogs Back

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Hogs Back
Location Map ( geo)
Cameraicon.png View gallery (4)
From:  Guildford (SU992494)
To:  Farnham (Runfold) (SU875476)
Old route now:  A31
Highway Authorities


Traditional Counties


Route outline (key)
The Mount Guildford - A3
A31 A3 - Hog's Back Hotel
A31 Hog's Back Hotel - Runfold

The Hogs Back is the road between Guildford and Farnham in Surrey, that runs along the top of a ridge 154m high connecting the two towns. It was part of the A31 on classification, and partly still is, though the western end of the modern road runs on a different route, while the eastern end has never been a classified road.


The Hogs Back in 1895, where the junction with the A3 now is. The parallel road to the north is the A31 Farnham Road.
Approaching the junction with White Lane, which requires crossing a lane of high-speed dual carriageway traffic

There has been evidence of a road running along the hilltop since Roman times, and it has been known as the Hogs Back since at least the early 19th century. The original route was via what is now The Mount from the western end of Guildford High Street, though the modern Farnham Road, taking a gentler ascent up the hill to the north, was established as the major route by the mid-19th century and ultimately became the A31. It was an important coaching route during the century between Guildford and Farnham, particularly since it was more direct than the railway which ran via Ash Vale. Despite this, it has never been a trunk road.

The eastern section of the Hogs Back was upgraded to dual carriageway in 1966 from the A3 to the Hog's Back Hotel, about halfway between Seale and Runfold, simply by putting down an eastbound lane to the north and keeping the original westbound. Though this was indented to make the road safer by preventing head-on collisions by fast overtaking traffic, it remained a notorious accident blackspot as vehicles now had to turn right onto a 70 mph road in a number of places. Since around 1990, there has been a 60 mph speed limit applied to the road. The junction with the B3000 is grade separated, while the junction with White Lane has had right turns banned, through it is still possible to exit the A31 onto the road and cross a lane of traffic.

The western end of the Hogs Back has never been dualled and was bypassed on a completely new alignment to the north in 1994. The Hogs Back Hotel is now accessible away from the mainline of the A31.


Looking at the Hogs Back junction from the A3 towards the A31 running overhead
The original junction, containing a single link road between the A3 and A31

The Hogs Back Junction is a free flowing interchange completed in 1934 when the A3 bypass was constructed. It is cut into the extremely steep Hogs Back, with the A31 going along the top and the A3 cutting through it.

1991 proposal for a replacement junction

Originally there was a single link road to the north that connected the two roads, both then single carriageway. The westbound sliproad was originally built in the late 1970s, following dualling of the Guildford Bypass. The A31 used to use an old alignment to the east of here and go along the Mount, which is a bit tricky because of the hill at the end. The older slip road continued to be two-way, allowing traffic to go from A3 north - A31 west, but this increasingly became an accident blackspot as it required crossing one lane of high speed traffic and merging with another, and so the movement was closed in 1989. The bridge on the 1970s western sliproad was discovered to be unsafe in the mid 1990s and closed for some time pending improvements.

The modern junction contains a grand total of three sliproads - A3 Southbound to A31 Westbound, A31 Eastbound to A3 Northbound and A31 Westbound to A3 Southbound. The B3000 provides the missing movements between the two roads further South and West, which fills in most of the other routes you need to try. Indeed, this link is signposted "B3000 (A3)" and "B3000 (A31)", implying it is a de facto part of the major road network.

Despite that, usually, a restricted junction between two dual carriageway A-Roads is usually a nightmare, this usually isn't too bad, except at rush hour.

In 1991 a new outer bypass was planned to replace the 1930s bypass which by now was showing its age in terms of geometry, especially the blind summit and sharp curve at Hogs Back which is well below current standards. The entire junction would have been demolished and replaced by a roundabout interchange allowing all turning movements to be made. This would eliminate the lengthy detour via the B3000 for traffic from the south wanting to use the A31 into Guildford. These proposals were abandoned.


Route To Notes


Portsmouth, Petersfield, Godalming (A3100)


(M25), London, Esher, Dorking {A25)


Farnham, Aldershot (A331)




Hogs Back
Related Pictures
View gallery (4)
A3 - A31 interchange at the Hog's Back - Geograph - 704305.jpgA31, Hogs Back - Geograph - 3539013.jpgHogs Back 1991 proposal.pngHogs Back Guildford 1973.jpg
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Junctions on the A31
Hogs Back • Shepherd and Flock • Hickley's Corner • Coxbridge Roundabout • Chawton Roundabout • Spitfire Roundabout • Bar End • Cadnam  • Rufus Stone • Stoney Cross • Picket Post • Forest Corner • Salisbury Road Junction • Verwood Interchange • Ashley Heath Roundabout • Woolsbridge  Roundabout • Azalea Roundabout • Palmersford Roundabout • Ameysford Roundabout • Canford Bottom Roundabout • Merley Roundabout • Lake Gates Roundabout • Corfe Mullen  • Roundhouse Roundabout • Red Post • Bere Regis Roundabout

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