Winter ice floes and spring flooding, which made ferry navigation hazardous, prompted the demand for a bridge.

The sections were floated into position by barge and then sunk into a shallow trench that had been dug into the loose sand and silt of the river bed.

This sedimentary layer may liquefy during a major earthquake,[12][13] leaving the tunnel with nothing to rest on, and thus vulnerable to total collapse.

In recent years, as the awareness of the effect of serious seismic activity developed, an engineering assessment and subsequent retrofit project was initiated to increase the survivability of the tunnel in the event of a significant earthquake.

This was the first application of a commercialized earthquake early warning system (EEWS) to protect critical infrastructure in North America.

[18] The bus had space for 9 bicycles and operated between late June until Labour Day on a route connecting Tsawwassen ferry terminal and Bridgeport station.

The replacement bridge, which was to be constructed starting in 2017,[20] would have likely eliminated the current height restrictions for over-height vehicles in the tunnel.

[21][22] On February 16, 2006, it was reported that the provincial government had plans to expand the tunnel's capacity, from four lanes to six, dubbed the "H99" project.

[23] On September 28, 2012, Premier Christy Clark announced plans to replace the aging tunnel within 10 years, addressing the congestion and safety issues currently plaguing the structure.

[20] On December 16, 2015, British Columbia Transportation Minister Todd Stone announced detailed plans to spend $3.5 billion on a bridge and interchange improvements to replace the tunnel.

[28] Preliminary work went out for tender in January 2017 to start the process of improving ground conditions for the future widening of the project area.

[32] Following their victory in the 2017 general election, the NDP Premier John Horgan scrapped the project in favour of a solution with more research and consultation with the Metro Vancouver mayors.

[4] On August 18, 2021, the provincial government announced the go ahead of the new eight-lane tunnel with a pedestrian and bicycle carriageway, subject to Indigenous consultation and environmental approvals.

[33] The provincial government has proposed that the George Massey Tunnel be filled with sand in lieu of full removal after the replacement is completed, or reused for BC Hydro electrical lines.