A39 "Deviation" Parracombe Bypass

[Isleworth1961]

It is said that the opening of the bypass sounded the death knell for the Lynton & Barnstaple Railway, which was struggling in the face of road competition (it struggled even before, when there was mostly horse-powered competition). Buses now had an easier route to take, and the journey time was even shorter for all traffic between the two towns, and the villages in between.

[Chris5156]

I don't think that the road numbers were used very much for navigation at the time, but purely for identification and maintenance and so rerouting the A39 onto the bypass would not have been seen as that urgent.

Until at least the mid-1930s it was standard practice to leave road numbers on their existing course when a bypass opened, and give the bypass a new number. It wouldn't have been unusual for the Parracombe Bypass to have been given a four-digit A-road number of its own when it opened, though it looks like that wasn't actually the case.

[WHBM]

This wasn't the first bypass of a 1 in 4 hill on the A39 along the Bristol Channel coast. At Porlock the "Toll Road" was built in 1840 to avoid Porlock Hill. The issue with the steep gradients was as much the inability of horse-drawn vehicles to manage them, both up and down, as it was for motors. Again, seen as much as an unemployment relief as a vehicle scheme. The end of Napoleon by the 1830s had seen major reductions in Army and Navy, which had traditionally absorbed much surplus labour in the area.

[vlad]

Until at least the mid-1930s it was standard practice to leave road numbers on their existing course when a bypass opened, and give the bypass a new number.

Not necessarily. As counter-examples, the ex-A1 through Colsterworth became the B6403, the ex-A6 through Garstang became the B6430, and the ex-A38 past a farm in Gloucestershire became the B4025.

I think it was standard practice to give the old route its own number if the original number moved onto the bypass. I assume there were reasons as to when the original number stayed where it was or moved onto the bypass - perhaps it was just purely administrative.