Link to link to link

Stephen Rees linked to Eric Doherty who linked to the Campaign for Better Transport in the UK.  And what did they all find?

The claimed benefits of new roads don’t work out in practice and some roads actually create new problems.

Duh.

But in this case, that conclusion is based on “post-opening project evaluations”  done for the Highways Agency itself.

They go back one year and five years after a new road is built, or widened, and look at the impact compared to what was forecast before the project started. In other words, they look at what was forecast to happen and what actually happened.  …

The five year after (5YA) reports found that overall traffic increased substantially once each new road was opened. This was substantially higher than the background level of traffic growth and each report attributed this to new trips generated by road building.

As Stephen notes, when it comes to hgihway projects like Gateway, “the model simply assumes that the same number and length of trips are better distributed on an enlarged network that has greater capacity.  But since induced travel is not factored into the equation, the forecasts are wildly misleading.”