|Location Map ( geo)|
|To:||Central Way, Cumbernauld (NS753738)|
|Via:||Stirling Road, Jane's Brae|
|Distance:||2.7 miles (4.3 km)|
|Meets:||A73, B8054, A8011|
|Route outline (key)|
The southernmost point of the B8039 is a restricted junction with the A73 at Riggend, giving access from the B8039 to the A73 in the southbound direction only. The Blackbog Road flyover of the A73, 500m to the north, provides access to the B8039 from the northbound A73 and there is also a slip from the southbound A73 here, but there is no access to the northbound A73 at this end of the route. These sliproads form a spur of the route. The B8039 then heads north, following the old line of the A73 along Stirling Road. At one time it passed between the houses at Luggiebank, but in the early 1980s a new road was built to improve access to Blairlinn Industrial Estate, by-passing the village. The old road now terminates at the old bridge over the Luggie Water and becomes a footpath.
The industrial estate is accessed from a roundabout, after which the B8039 reverts to a northerly direction. The new alignment ends just before it meets the B8054 Lenziemill Road at a half-built dumbbell junction, where the flyover was never constructed, leaving just the two roundabouts at the end of what would have been the sliproads. Although the B8054 terminates here, a road continues west to meet the A73 at a roundabout, providing the missing movement from the southern junction. Beyond the junction, the road is dualled, and just as the two carriageways come together, sliproads leave for the next junction. This is a complete GSJ, albeit with the unclassified South Carbrain Road. Continuing as the dual-carriageway Jane's Brae, the B8039 runs north and meets a pair of south-facing slips with the unclassified North Carbrain Road immediately before reaching its terminus at a final grade-separated junction, the Langlands - Seafar Interchange. This is a squished Trumpet design, with the A8011 in central Cumbernauld; the junction merges into the adjacent roundabout GSJ so is more complicated than it appears.
Being a route through a New Town, the history of the B8039 is short but complicated. The first parts of what is now the B8039 were built in the mid-late 1960s, with the section from the Langlands - Seafar Interchange south to the Janes Brae Interchange shown on mapping from c1967. However, at this time this southern junction was part built and the road beyond not yet constructed, with the A73 still weaving its way through Cumbernauld. The 1971 OS Quarter Inch map shows an interesting (although possibly inaccurate) situation, with the A73 re-routed onto its current alignment, and the B8054 following its older route. There is no mention of the B8039, not even as an un-numbered B road, nor is there any suggestion of the junctions noted above which are depicted on older, larger scale maps. However, the One Inch sheet from the same year does show the B8039, but the B8054 still continues through to meet the A73.
The 1974 OS One Inch sheet almost shows the finished route, with the B8039 now starting and finishing as it does today, and specifically labelled at each end. However, the junction with the B8054 is unfinished, with the dual carriageway shown as being forked for the proposed dumbbell, but the route then has to turn left and follow Lenziemill Road (now the B8054) north east for a short distance to find the old A73 route, which is now just a footpath. Although it seems unlikely, it is possible that this slightly convoluted layout remained in place until the Luggiebank Bypass was built around a decade later.