The standard width of a hard shoulder is 3.3m, for a regular lane it is 3.65m. Additionally there is a hard strip adjacent to lane 1 on an ALR, which there obviously isn't adjacent to a HS, so ALR provides considerably more space.Ruperts Trooper wrote: ↑Wed Dec 22, 2021 11:13Is that true? My recollection of the original motorways is that the hard shoulder had to be redone with deeper foundations to allow contra-flow when the first round of resurfacing was needed.
ALR works include slight widening of the carriageway to accommodate this, either into the verge or by shifting the lanes slightly right and narrowing the central reservation (concrete barriers are often installed at the same time).