(15 Nov 2015, 5:08 pm)Lm2606 wrote To be honest, the X15/X18 is always subject to delays due to just the A1 in general
Hmm, I use those two routes frequently, and any delays I've experienced have never been to do with the A1. In reality the A1 stretches are where time can be made up.
Especially on the X18, you'll find that busy junctions, tight corners, and uncontrollable circumstances (horse riders on twisting roads etc) are usually the factors behind late running.