One of the arguments used by proponents of the Silvertown road tunnel is that it will allow new bus routes to be established across the Thames. However British Pathé film coverage of the opening of the second Blackwall tunnel by Desmond Plummer in 1967 prominently shows double decker buses running through the Blackwall tunnel. What are the actual restrictions that currently prevent far more bus routes operating across the current Blackwall tunnels?
The current issues of severe congestion, poor reliability and a lack of resilience at the Blackwall Tunnel are the fundamental restriction on running new/improved bus routes across the Thames in east London. This means the current single decker 108 bus service is the least reliable service in Newham and Greenwich. The Silvertown Tunnel, with associated user charging and new cross river bus connections, is the best solution to these issues.
Further, the Blackwall tunnel has inherent design limitations which restrict the types of vehicles that can use it. When the second Blackwall Tunnel opened in 1967, it operated a contraflow which allowed traffic in both directions. This meant that double decker buses could operate. While this might have been the case in 1967, the removal of the contraflow, along with height restrictions, width restrictions, tight highway alignments, modern vehicle designs and tunnel safety standards mean it is no longer possible to safely operate double-decker buses through the Blackwall tunnels.