On Thu, 6 Feb 2003, at around 10:38:38 local time, Dave Massey
<105671.471@compuserve.com> wrote:
>Message text written by Michael Hargreave Mawson
>>Milton Keynes is a "new city" designed from the ground up to be served
>by a grid-pattern of dual carriageways (not sure whether these are what
>Americans call "four-lane highways" or "two-lane highways"<
>
>Your "dual carriage ways with the centeral reservation" is what we call
>"four lane divided highway."
Ah - thank you for that.
> "Limited access" means there are no cross
>street intersections and all roads cross either over or under bridges and
>entrances and exits are via merging and diverging ramps which allow cars to
>enter and exit the traffic stream at or near traffic speed. (although this
>fact seems to escape some drivers) All of our "Interstate" routes meet
>these qualifications. Equivilent to your "M" routes and "A" routes.
"M" and "A" roads are a bit more complicated than that...
An "M" road is a "motorway". It usually has three lanes in each
direction, separated by a central reservation, and with merging and
diverging ramps as you describe (we call these ramps "slip roads").
However, some motorways have only two lanes in each direction, and many
come to an abrupt end at a roundabout, or peter out into a two-lane
highway.
An "A" road can be many things. The A1(M), for example, is
indistinguishable from a motorway. The A1 (same road, a bit further
north) is a four-lane highway (divided for most of its length) with cars
entering and leaving the road both from side roads and via roundabouts
(it is great fun trying to turn across the traffic onto a side road when
there is a constant stream of traffic in both directions, averaging over
70 mph). "A" roads with one, two or three numbers after the letter A
are "trunk roads" - i.e., they are considered to be arterial highways.
Some single-digit A-roads are two-lane undivided highways for much of
their length, with occasional four-lane-divided stretches. Many (most)
of the two- and three-digit "A" roads are two-lane undivided highways.
All four-digit "A" roads are two-lane undivided highways, and are not
considered to be trunk roads. Many "B" roads are wider and more suited
to heavy traffic than some "A" roads!
I believe that it must have taken someone with the peculiar genius of a
Lewis Carroll to come up with the designations for British roads.
> Some
>road ways not designated as "Interstates" also meet these qualifications,
>but not many.
>
>Also, most urban interstates have more than two lanes of traffic in each
>direction. The whole business has mushroomed to utter confusion to the
>outside observer.
>
>(Mind the gap)
Will do! <g>
ATB
--
Mike
Ellie - 1963 White Herald 1200 Convertible GA125624 CV
Connie - 1968 Conifer Herald 1200 Saloon GA237511 DL
Carly - 1977 Inca Yellow Spitfire 1500 FH105671
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