I was surprised that London's outer loop was so much bigger than Beltway 8, probably about the size of the Grand Parkway (not beltway) Someone who knows, how dense is London inside that big M 25 loop? I was a Land Planner for the firm that coordinated the effort for the Grand Parkway in the 80's. A lot of very wealthy folks were buying suburban land within the conceptual plan and filing plats dedicating R.O.W. for the GP. The plat designation was always Grand Parkway, the State had not yet adopted the plan to designate it TX. HWY. 99.
Educated guess says London is much more dense. London- 9.5 million pop / 1650 sq miles Houston- 5.4 mil / 4600 sq miles Numbers may've fluctuated since these stats, but not that damn much. New York is kinda irregularly shaped.. a Houston-type Loop system isn't as feasible. Ditto LA and CHI. Their CBD's are too close to the coast.. their "beltways" would be more what Swoly was describing.. open skirts.
