From high-speed rail to the Olympics, why do big projects go wrong?

Lots of countries have big construction projects that become a byword for ineptitude. In America the “Big Dig”, a highway project that snarled up the centre of Boston for years, came in five times over its initial budget. The stadium built for the Montreal Olympics in 1976 was unaffectionately known as the “Big Owe” after costs overran massively; the debts from the games were paid off only 30 years later. Even the Germans get…