Martin Underwood wrote:
Paul Terry wrote in
ine:
In message , James
writes
Since the Tower Bridge limit has apparently been there for half a century,
I think it unlikely:
I too thought that until recently (maybe about five years ago) the lowest
*enforceable* speed limit was 30, which was why councils splattered roads
with speed humps and chicanes to try to impose a physical as opposed to
legal restriction.
But I know that 20 limits are now enforceable. The main road from
Beaconsfield to Slough is mainly 30 but has 20 limits for about 50 yards
either side of every traffic light junction over a half-mile stretch - I
think there are four of them. It's tedious driving along a road which is
wide and straight, and has service roads either side so through traffic and
stopping traffic is kept separate, so even 30 is a bit slow and 20 is
painfully slow. I cannot help thinking that traffic which has priority is
being penalised for the sins of pedestrians and othe drivers who fail to
observe the traffic lights - but this seems to be morally acceptible in this
Brave New World.
I'd like to see much more use of repeater signs where slow speed limits
apply: on every single lamp-post and painted on the road - and maybe even as
flashing number-in-a-red-circle signs which light up if you're over the
limit. Hopefully if you're observant you'll see the first sign at the start
of the restriction, but I find I need it drummed into my head constantly to
avoid me speeding up subconsciously to a speed that feels appropriate.
20mph speed limits have always been enforceable but were very rare
until the "20mph zones" started to appear in residential areas in the
early 1990s (until that time speed-limits lower than 30mph needed
special authorisation by the Secretary of State for Transport). The
government guidance (Department for Transport) is that 20mph zones
should be largely self-enforcing through traffic-calming measures or,
in the case of new roads, designing a low-speed carriageway layout.
However, Tower Bridge is not a 20mph zone. This 20mph speed-limit is
there for structural reasons - the bridge may be damaged, or worn out
much faster, by constantly higher speeds. Road-humps presumably can't
be used because lorries going over them would vibrate the bridge and
cause the same damage. Rotherhithe Tunnel is another example of a
20mph speed limit without traffic-calming.
I do not believe there are any speed limits of less than 20mph on
public highways in the UK. I doubt the police can specifically enforce
the lower limits that are often signed on private roads and in car
parks, although they might well be able to arrest you for something
else if they saw your fast driving as dangerous.