High-speed rail would revolutionise interstate travel and would also be an economic game-changer for dozens of regional communities along its path.

Thanks to the Interstate Highway System, it is now possible to travel across the country from coast to coast without seeing anything.

What we see today is an American economy that has boomed because of policies and developments of the 1950s and '60s: the interstate-highway system, massive funding for science and technology, a public-education system that was the envy of the world and generous immigration policies.

The logic is often far-fetched - how does medical marijuana affect interstate commerce? - and some conservatives would like judges to start throwing out federal laws wholesale on commerce clause grounds. The court once again said no thanks.

Some infrastructure projects clearly require massive, coordinated investment - interstate highways or a new trans-Hudson tunnel, for instance. Others don't have to. We should be unafraid of pilot projects and learning.

Thanks to the Interstate Highway System it is now possible to travel across the country from coast to coast without seeing anything.

What we see today is an American economy that has boomed because of policies and developments of the 1950s and '60s: the interstate-highway system massive funding for science and technology a public-education system that was the envy of the world and generous immigration policies.

The logic is often far-fetched - how does medical marijuana affect interstate commerce? - and some conservatives would like judges to start throwing out federal laws wholesale on commerce clause grounds. The court once again said no thanks.

Discount air fares a car in every parking space and the interstate highway system have made every place accessible - and every place alike.