In article , John Rowland
wrote:
"Michael Bell" wrote in message
...

Junction 8 on the M1 was designed "wrong way round"
in Mrs Castle's time to test the idea of designing junctions
so that they could be changed over to right-hand drive,
but the experiment was never repeated.

In what way was it designed the wrong way round? Just wrong gradients and
curvatures?
[snip]

It is a normal "trumpet" interchange where a non-motorway road joins a
motorway. Where any road crosses another, driving on either side of the
road, before the non-motorway road crosses the motorway, there are two slip
roads which can be filled in simply. But when the non-motorway road
has crossed the motorway, its two carriageways are the wrong way round
to join onto the motorway. In a normal British trumpet interchange the
left carriageway turns 270° left and under itself to join onto the motorway
and the lane coming off the motorway turns off the motorway well before
the junction and makes a wide sweep round. In the case of this interchange,
when you come off the motorway, you first pass under the bridge and then make
a sharp turn left. It's a route I do about once a month, and it is easy to
see you might try to get round too fast.

Michael Bell

Normal British Left-hand layout :-

/--------------\
/ \
/ \
/ /----\ \
/ / \ \
/ | \ |
/ | | |
/ \ | |
/ \ | |
--------------------------------| |-----------------------------------
Motorway Motorway
--------------------------------| |----------------------------------
\ | | /
\ | | /
\ | | /
\ | | /
\ | | /
\ | | /
\ | | /
\ | | /
\ | | /
| | /
| | /
| | /
| |
| |


Far from scale, but I hope you get the idea.

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