Yesterday, I was on the 87 from Oldbury to Birmingham. High Street is closed from the Trinity Motors end up to Stony Lane. So, routes 80 / 87 are missing out the High Street section from Galton Bridge to Trinity Motors. Misses all the congestion and must be saving several minutes.
About a month back when Swan village (just off the Birmingham New Road by Roseville) was having Road works done, the 81 was diverted straight up Birmingham New Road which cut out a good 5-7 mins making the service more reliable as well.