Building the road in a cutting would cost up to £10-5 million per kilometre.

In 2001 its population was 272 - c. 6 people per square kilometre within an area of 45 km2.

The population density of the city is 1,233.6 people per square kilometre.

As at March 2001, there were an estimated 4.3 people per square kilometre.

This is a population density of 87 people per square kilometre.

It has more cars per square kilometre than anywhere else in the world.

In addition, tunnel will cost close to one billion dollars per kilometre to build.

The average time to build was four years and the construction cost worked out at about a fifth that of main lines per kilometre.

The density of population was estimated at 1,157 people per square kilometre.

I would add that the objective for 2020 is 80 grams per kilometre.