Todd you might also comment that regulated speeds can dramatically increase
road capacity.
The German Transport Miinistry produced Stadtverkher im Wandlung (changing
traffic in towns?) This included an interesting diagram depicting how at reduced
speed drivers require a smaller dynamic envelope for safe vehicle spacing,
and a number of other factors such as lane changing etc show that when speeds
are reduced with good observance of the limit, road capacity increases, and on
multi-lane roads an additional lane can often be added.
The UK has also delivered this in a practical form on the M25 where enforced
variable speed limits have kept traffic moving and improved the flow rates by
geting all vehicles conforming to the same speed profile.
A similar detail can, I believe deliver some interesting potential for bus
services at a regional centre. By terminating local services from the
hinterland at peripheral Park & Ride sites and changing bus (the P&R site provides an
almost instant connection in to town and waiting facilities for the local
service outbound) Then the service pattern of buses travelling along a dedicated
corridor becomes standardised in vehicle type and stopping pattern and low load
factor rural services no longer require road space, and more important bus
stances at the journey's end. We are seriously in need of this type of detail
in Glasgow, where the streets are clogged with half full buses which either
run-in or pass through the centre on 2-4 core streets. Many travellers would
gain from outer cross-river services which simply shuttled between the core
corridors North & South of the river - MVR 1 or 2 vehicles with transfer ticketing
as it is the core soaks up vehicles through the delays in getting through it.
But that is slightly OT uless you note that with a 20mph blanket speed limit,
the traffic might actually flow through the city more freely.
Dave Holladay
Glasgow
|