Configuration
The tunnel is a single tube that is subdivided with a concrete wall, each side containing two traffic lanes. The typical traffic flow has two northbound lanes in the east tube and two southbound lanes in the west tube. In 1989 a counterflow system was introduced to meet increasing traffic demand in the tunnel.
At peak rush traffic periods, a reversible lane system is used, with a series of swing gates deployed reducing traffic in one direction to a single lane, while increasing the other direction to three lanes. Morning rush has three lanes northbound (inbound to Vancouver) and evening rush has three southbound lanes (outbound from Vancouver).
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