Blackwall Tunnel height.
As we were introducing a better height limit warning and diversion sign
regime to the tunnel approach roads, we took the opportunity of checking
the internal measurements of the tunnel to ensure the height limit
displayed was correct. This exercise proved that the height limit of 4.0
metres was correct and did not need to change. However, as we were
introducing new signs on the approaches to the tunnel, the new signs had
to be in accordance with the current legislation; thus, the imperial
figure of 13’ 4” had to be amended to 13’ 0” to comply with guidance
contained in Chapters 3 and 4 of the Traffic Signs Manual.Therefore, early in 2010, we introduced new signs on the A102 and A2
showing 4.0m/13’0” height limit (instead of the 4.0m/13’3”) and at the
same time amended all the existing height limit signs to ensure
consistency.