Originally Posted by corporate-wage-slave

It's neither regular nor irregular - it's not usually more than 1 night a week. The tunnel is known to regulars as HVT, Heathrow Vehicle Tunnel, or sometimes the Heathrow Spur Tunnel, linking the M4 and A4 (Bath Road) to Heathrow terminals 2 and 3. There are separate West and East tunnels for north and southbound traffic. There was a big £85 million refurbishment project that ended earlier this year but every so often they close one tunnel or the other for cleaning and other maintenance, forcing two lanes down to one in the process. There are some big vent devices that need to be checked regularly.

The problem is the corner of the T2 building, where the lane switching means there is a bottleneck at a particular set of traffic lights, it's not usually so bad at the A4 end. It also backs up the bus egress too, much to the frustration of airport staff after a 12 hour shift.

On the nights when this happens, the tunnels are closed at 22:30 hrs and re-opened at 05:30 hrs (sometimes a bit before).