With a price difference of A$20 million the decision to build a two-lane tunnel was criticised in some circles as short-sighted.

NZTA's traffic modelling indicates the capacity of the two-lane tunnels would be reached within 10 years of operation.

This cost included $5 million for a two-lane tunnel to connect Dawes to Standard.

As traffic levels increased, bottlenecks at the two-lane tunnels on the Pennsylvania Turnpike became a major issue.

Originally, a two-lane tunnel was considered, but the costs for a four-lane bridge were found to be equivalent; thus the bridge was the choice.

The Holland Tunnel consists of two one-way two-lane tunnels.

This road is a two-lane highway that includes a pair of two-lane tunnels that go right through the top of the mountain.

An upgrade of the two-lane tunnels was proposed but has not been carried out.

While there has been planning work done to expand tunnel capacities as well, the facility currently continues to utilize only the original two-lane tunnels.

The two-lane tunnel is expected to reduce downtown bus traffic 25 percent by next fall and 40 percent by the end of the decade.