In message , David of Broadway
writes

http://www.tfl.gov.uk/tfl/pdfdocs/cen_bus.pdf

That's more along the lines of what I'm looking for, although I'd like
to see a proper map, superimposed on a street map.

While I agree in principle, it would simply not be possible in central
London where there can be as many 15 routes (plus night buses) passing
along one street. Either the map would have to be enormous, or there
would have to be considerable topographical distortion to fit in the
number of differently coloured lines. The alternative is the style of
the quadrant maps which you say (and I agree) are not all that clear.

Good point -- the bus route network is much denser in London than in
NYC. I wonder why that is.

Partly historic reasons - London's early adoption of railways and tubes
resulted in an infrastructure that is difficult and expensive to adapt
to modern needs, so buses were an important adjunct to the transport
system from the late 19th-century onwards (in fact, many of the more
tortuous routes still follow the lines of 19th-century horse-bus
routes).

Partly demographic reasons - In 1880 NYC's population was only just over
1.2m whereas London's was already three times that size. With little
room for new roads or new railways, buses and trams were the only
solution.

Partly social reasons - traditionally, buses provided a cheap form of
transport and the network was taken under state control at an early
stage. Today, it is still a highly regulated network and (as Paul C
rightly states in this group) benefits from a "virtuous circle" in which
high frequencies make it popular, and so generate more and more traffic.

Partly environmental reasons - only today the London Congestion Zone has
been expanded, making it prohibitively expensive (when combined with car
parking charges) for most of us to drive into Central London. Thus there
is a strong demand for public transport, of which buses form an
important part.

(I'm a car owner, living 8 miles from the centre of London - but I would
almost always go into that centre by railway or bus + tube: taking the
car usually makes no economic sense.)
--
Paul Terry