The A766 (renumbered from the B706 in the early 1930s) runs from the A701 near the centre of Penicuik to the A702 near Nine Mile Burn in Midlothian.
Route
Braidwood
The eastern terminus of the A766 is at a T-junction with the A701 / A703multiplex a little to the north of the town centre in Penicuik. From this point the road heads in a westerly, then south westerly direction along Carlops Road, with housing on the right and sports fields to the left. The B6372 turns off to the left in the middle of the sports fields, doubling back to the town centre. After approximately ½ mile, the A766 leaves Penicuik and passes through a band of woodland. A few gentle bends carry the route around the wooded grounds of Penicuik House before a long straight climbs a little across farmland, with further patches of woodland. Halfway along the straight, the route crosses the Braidwood Burn at Dean Bridge. The burn is at the bottom of a steep gulley, producing a very sharp dip in the road, which remains almost dead straight. After passing Braidwood Farm, the route kinks a little to the left onto another long straight, which climbs gently to the routes summit at around 280m.
The summit is also the western terminus of this short route, an unsignalized, acute-angled T-junction with the A702 set at the foot of the Pentland Hills. There are turning lanes for traffic turning into the A766, but traffic turning right onto the A702 has no such benefit, although it is admittedly not a common movement.. A fine view of the Pentland Hills is available from this point. The small settlement of Nine Mile Burn is nearby to the southwest, further along the A702. To the south and east of the junction is bleak moorland, but there are fine views of the Pentland Hills on the final approach.
History
The B706 survived until at least 1928
As noted above, the route was originally numbered as the B706 in 1922. The revised MOT map of 1928 still shows this route number, but by the Ten Mile Map of 1932 the route had been renumbered as the A766, which it remains. The only suggestion that the route has seen any realignments is a meandering pavement at the junction with Rullion Road in Penicuik. However, old maps suggest that this is not the case, and that the pavement was built to serve the properties, which are set back behind grass, rather than indicating a junction improvement.