170Built systems, built areas, and whole regions
LondonBerlin+Rome+Bucharest+Stockholm+Barcelona+NantesChicago+San Diego/Tijuana+Philadelphia+Ottawa- Edmonton
PortlandAtlanta- Mexico City
SantiagoBrasilia+TegucigalpaIquitos- Cairo
*
Nairobi+Bamako+East LondonAbecheBeijing*
MoscowSeoul*
Te h r a n*
Sapporo+UlaanbaatarErzurumKagoshimaBangkokKuala Lumpur+CuttackSamarindaCanberraRahimyar Khan•
Europe North
AmericaLatin
AmericaAfrica West-East
AsiaSouth Asia-
AustraliaAverageNumber and type of primary radial roadsextending outward beyond metro areaGeographic area, with cities from large to small population0
1
3
5
7
9
11
13
= Two laned pave (sealed)= MultilaneFigure 7.3Radial roads extending outward from a metropolitan area relative to
geography and city size. Radial roads extend≥20 km beyond the metro area border.
See Figure 7.2 caption.green wedges between the radials and extending into metropolitan areas are
likely to be present. Connected greenspace in wedges facilitates the movement
of species inward and nature recreationists outward from the city. Breaks in
thestrip development for stream/river corridors and wildlife movement are
important.
[S2]In Europe, ring highways are widespread and extend an average 56 % of a complete
ring outside the metro area, whereas elsewhere all ring roads are <50 %, and the average
is 25 %(Figure7. 2).
An effect of geography is evident for this pattern. Europe, which combines
adense population with high vehicle use, has mainly chosen the outer-ring-
highway design. Europe’s cities tend to spread concentrically, or dispersed towns
and villages become nuclei for urbanization which later threatens to coalesce.