Although the northern end of the 'true' pass begins near the point where Stake Beck reaches the valley of Langstrath, it is pretty obvious that the route itself was actually intended to link Borrowdale and Langdale rather than Langstrath and Langdale. With the route offering the nearest thing to a direct line from Borrowdale to the south east of the county it stands to reason that this would have been a comparatively busy thoroughfare in the past. It removes the need to travel via Keswick and Dunmail Raise, and although rising to a height of almost 1600ft asl the pass is quite easy going.
Having walked both sides of the pass many times over the years, I don't understand why it was never upgraded to be suitable for motorised traffic. I should add that I'm thankful that it wasn't.