Remove, Replace or Retrofit the Massey Tunnel?

The Netherlands are retrofitting a similar tunnel to modern standards.

The George Massey Tunnel was modeled on the Maastunnel in the Netherlands which was built 20 years earlier. Instead of replacing their tunnel with a bridge, the government of the Netherlands is currently upgrading their tunnel at a cost of $262 million Euros – about $420 million Canadian dollars.  In comparison, a new bridge over the Fraser River is expected to cost at least $3.5 Billion dollars.

Is a new bridge over the Fraser River the best place to spend our limited public infrastructure dollars?  Can we upgrade the Massey Tunnel instead and spend the money saved on other projects, like public transit?