Road closing.
Why do they feel the need to close a whole road rather than stick traffic lights up and close one side? Road damage repair this morning, no fucking advance (previous day) warning. The damaged bit was only on one side of the road. My diversion took me along a mile of single lane track, you can imagine what that was like with all the fuckwits just piling through.
Pretty sure the answer will be worker safety - unfortunately enough people drive like absolute cunts past workmen that it's not worth taking the risk in most cases.