(3) - Arriving at the figure of 34 sq. miles. This gets a bit numerical !

Land area of Venice -

Approx. area of Venice - Main city (Rialto islands) = 5.6 sq. km, Giudecca = point 8 km, San Giorgio (Abbey) point.15 km, San Michele (Cemetery) point.15, Murano 1.1 sq. km. Tot = 7.8,
This is only an estimated figure, it includes short stay car parking, bus marshalling area, harbour and rail areas. It excludes the water area within the harbours and excludes the long stay car parks.
(7.8 kilometres ^2 = 3.0115968 miles ^2)

Population of Venice -

Because a tourist destination functions differently from a normal city I have based the population estimate of Venice largely on its 1950 figure, as this predates the rise of mass tourism, in 1950 the resident population was 175 k, Venice’s island resident population today stands at 65k dropping by approx. 1.5k per year, to this needs to be added unregistered students, visiting tourists and those staying in properties held as holiday homes. Venice receives 17/18 million tourist per year, about half of visiting tourist are day stay with an estimated 20 million individual night stays. Peak season holiday visits average about 80k per day and in extreme cases can rise to 150k (these figs are for 2006). this leaves us free to choose any figure between about 90k as a low season night population to 220k as a high season day population. The estimate I have used is based on 150k.

Auto space Houston -

Parking space is estimated for Houston at 30 spaces per vehicle (Asphalt Nation, page 64, Jane Holtz Kay, 1998, isbn 0-520-24620-2.
(An extreme example but perhaps not heavily out of line with the purest forms of the automobile city).

Parking space estimated at about 300 sq. foot (approx. 200 for vehicle & 100 for access)

Car ownership per 1000 estimated at about 650

(1 mile = 5,280 feet = 1.609 344 kilometres)

150,000 x 65% = 97,500 x 30 x 300 = 877,500,000 sq. foot -/- by 27,878,400 sq. ft = 31.47 sq. miles

Road space Houston -

(US Bureau of census, Lane miles per 100 households, LA 1.64, Houston 3.5, Chicago 2, New York.74 -
http://photos1.blogger.com/blogger/7751/2272/1600/tab1.1.jpg - Accessed Nov 07

3.5 miles of lane per 100 household = 185 ft per household. Average population per household 3.3, therefore lane per person 56 ft, average lane approx. 12 ft wide, roadspace per person 56 x 12 = 672 sq. ft

The overall figure of 34 Sq. miles is consistent with a city of 150k at a density of 2500 per sq. mile allocating approx. 60% of land area to auto infrastructure.