I suppose if they give you the official diversion in advance, you can plan to avoid it and take a different route. They have closed a major road near me for 6 weeks, to lay a new sewer (having only newly surfaced it last September!!! Well done Council. Good planning) and the official diversion uses the only other major road going in the same direction. Thankfully I leave too early and get back from work too late, to be bothered by any traffic on the diversion. However there are two alternative unpublicised routes that are free from traffic and save between 10 and 15 minutes of queuing for an extra half mile travelled.