In reality initially is this going to cause that much of an issue actually on Derby Rd? The only part affected is the bottom of St Augustines whilst they make it wider for longer so you cant come down the hill to the lights so people doing that will be affected by it, traffic on Derby Rd can still travel along it both directions without being affected and, initially, you can still turn up St Augustines. Its going to be a pain for folk wanting to come down to Derby Rd from Whitecotes way but along with the actual diversion there are a number of other ways of getting to there.
I generally dont need to go down that way in a morning but looking on Google Maps traffic flow currently its showing as Green so no issues all in that area.