From Roader's Digest: The SABRE Wiki
The A68 can be split into three main sections: the first forming part of an Edinburgh-Newcastle primary route through the Scottish Borders, offering a safe (if not particularly fast) alternative to the appallingly underdeveloped A1, the second follows the "Dere Street" Roman road, south to the Tyne at Corbridge, and the last section passes through County Durham to the A1(M) and Darlington. So the A68 is really another Newcastle bypass.
Section 1: Edinburgh - Otterburn
The A68 starts at a grade separated junction on the A720 Edinburgh City Bypass, running around Dalkeith to the north. The road runs on a new high quality alignment, until it reaches Pathhead. The A68 continues to climb towards the Lammermuir hills, and at Soutra Hill becomes 3-lane with crawler lanes for several miles over the top of the hill. There are snowgates here, which are surprisingly often used, and also a very large wind farm with some pretty hypnotic windmills either side of the road.
Descending into Lauderdale, the first main junction is now a roundabout at Carfraemill where the A697 heads left (SE). The A697 primary is an alternative to Newcastle, less prone to snow, but no longer signposted to Newcastle here. The A68 is good here, largely realigned, and fast (hence plenty of cameras) passing through Lauder and Earlston, and crossing the Tweed at Leaderfoot by a 70s concrete bridge (the old one still exists, single track with refuges for pedestrians). Near here at a roundabout the new A6091 heads west to Galashiels, connecting with the A7 and forming the trunk road to Carlisle.
Newtown St Boswells, 'capital' of the Scottish Borders is bypassed to the east, and at St Boswells, the A699 crosses from Selkirk to Kelso. Here, the A68 follows Dere Street for the first time, albeit briefly: a straight switchback section of the road leading to the A698 turnoffs (west to Hawick, east to Kelso) and then to Jedburgh (nice abbey). South of Jedburgh, the A68 begins to climb again, eventually a set of gentle hairpin bends taking the road up to Carter Bar, fantastic views and the Scotland-England border. The border is marked with a viewpoint and a border signpost which includes the probably redundant reminder that in both England and Scotland we drive on the left (in half a dozen languages). The A68 loses its trunk status at the border and becomes locally-maintained.
Now the A68 descends into Redesdale and thick forest for much of this bit, and remains a mixture of bends and reasonable straight bits, past the Otterburn army training ground and the Brigantium exhibition, which includes a reconstruction of a section of Roman Road.
Section 2: Otterburn - Corbridge
After crossing the River Rede, the A68 joins the Roman Dere Street which has taken its own route across the Cheviots via Chew Green (part of which is still in use by the military to this day). This section is very straight and very hilly, with particularly steep gradients at West Woodburn. Because the landscape is not heavily vegetated, it is possible at several places to see the road carving a path over several ridges ahead, dead straight. However, the blind summits make this a trap for the unwary, who are tempted to overtake at inopportune moments, and dire warning signs are provided to make this point. The switchback A68 passes through crossroads with the B6320 Otterburn/Bellingham, A6079 Hexham/B6342 Rothbury. We now come to a roundabout, which marks the junction with the B6318: a more recent military road, built in Georgian times to assist in troop movements during the Jacobite uprisings. This section of the Military Road used Hadrian's Wall as its foundations, so there is little of the Wall itself to see here.
Another steep descent takes the A68 to Corbridge and the A69 bypass, where we part company with the Roman Road.
Section 3: Corbridge - Darlington
Originally the A68 met the A69 in Corbridge, and then multiplexed with it across the River Tyne on a seven-arched bridge which has single alternate lane traffic before heading east to Riding Mill before turning south again. Now the A68 and A69 multiplex for a few miles past Corbridge before parting company at a roundabout, which looks like it should be a GSJ but isn't. After this the A68 heads south across the Tyne, up the hill out of the valley across the A695 and back onto its original line south of Broomhaugh, crossing the line of Dere Street on the way.
Although some of the next section is very straight, Dere Street itself is some miles to the east, following the B6309. The A68 now keeps to the high ground above the Derwent Valley, until descending steeply to cross the Derwent at Allensford and entering County Durham. At Castleside the A692 leaves for Consett, and the A68 continues over the moors towards Wolsingham. It winds its way through Tow Law, and crosses the A689 at a roundabout. The River Wear is crossed by a modern bridge at Witton-le-Wear, one of the few off-line upgrades the A68 has, but at High Etherley at has to suffer the indignity of giving way to a B road where it meets the B6282 in a TOTSO junction.
On to West Auckland where it used to cross the A688 in a short multiplex on the green. The other road now bypasses the village but things have not changed, so the A68 turns left at a mini-roundabout then TOTSOs right on an unclassified road. The A68's exit (via another mini-roundabout) looks initially unpromising, but soon opens out again. After a roundabout and the current line of the A688, Dere Street is crossed again, becoming the B6275 on the right hand side which joins the A1(M) at [Barton Interchange|junction 56]], about nine miles away. We, however, are going to Darlington, so continue on the A68 until it is joined by the A6072. Now comes the first dual carriageway section of the A68, (except for the A69 multiplex), so it is a bit of a let-down to see it signposted with a white (non-primary) signpost. This short dual-carriageway section leads to the A1(M) junction 58. Beyond here the A68 continues, now really non-primary, to end in the centre of Darlington. The very last section is another dual carriageway, part of the inner ring road, meeting up with the A167.
Original Author(s): A835(T) and T1(M)