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jackal wrote: ↑Thu Jun 24, 2021 06:48
Besides, there's not really much arguing that 25k AADT isn't possible when it is the actual observed volume!
There is because you're not addressing how that much traffic can cope coming to a halt at a single lane but not be able to cope with a single lane free flowing? The Ilminster bypass has a higher AADT and it's S2+1.
S2+1 isn't WS2, and the Ilminster Bypass is a blackspot in line for upgrade anyway. Hardly the model for the M49 that you suggest. As Bryn said, there's nothing wrong with having a road that can (shock!) handle its volume of traffic.
I already said the M49 northern terminus is inadequate. The optimum situation would be a freeflow junction there but with the road otherwise as built. I really don't see why you're objecting to this.
jackal wrote: ↑Thu Jun 24, 2021 06:48
Besides, there's not really much arguing that 25k AADT isn't possible when it is the actual observed volume!
There is because you're not addressing how that much traffic can cope coming to a halt at a single lane but not be able to cope with a single lane free flowing? The Ilminster bypass has a higher AADT and it's S2+1.
I think if the M49 had been built as a single carriageway road we'd all now be complaining that it was a slow crawl at 56mph behind a line of trucks, with oncoming traffic mostly too heavy to permit overtaking, and asking why its designers had been too stingy to provide a dual carriageway. We'd also be unhappy about the fact that the new junction for Avonmouth had been built as a flat roundabout, interrupting the road, because a GSJ would never have been provided on an existing single carriageway.
jackal wrote: ↑Thu Jun 24, 2021 06:48
Besides, there's not really much arguing that 25k AADT isn't possible when it is the actual observed volume!
There is because you're not addressing how that much traffic can cope coming to a halt at a single lane but not be able to cope with a single lane free flowing? The Ilminster bypass has a higher AADT and it's S2+1.
I think if the M49 had been built as a single carriageway road we'd all now be complaining that it was a slow crawl at 56mph behind a line of trucks, with oncoming traffic mostly too heavy to permit overtaking, and asking why its designers had been too stingy to provide a dual carriageway. We'd also be unhappy about the fact that the new junction for Avonmouth had been built as a flat roundabout, interrupting the road, because a GSJ would never have been provided on an existing single carriageway.
As well as the fact it would inevitably be 50 mph with average speed cameras as well...
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
jackal wrote: ↑Fri Jun 25, 2021 07:21I already said the M49 northern terminus is inadequate. The optimum situation would be a freeflow junction there but with the road otherwise as built. I really don't see why you're objecting to this.
IIRC it was built as a full roundabout to allow traffic on M4 to turn around before the toll booths if they didn't have the money for the toll. It also provides a degree of redundancy for when M5 is jammed past Cribbs.
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jackal wrote: ↑Fri Jun 25, 2021 07:21I already said the M49 northern terminus is inadequate. The optimum situation would be a freeflow junction there but with the road otherwise as built. I really don't see why you're objecting to this.
IIRC it was built as a full roundabout to allow traffic on M4 to turn around before the toll booths if they didn't have the money for the toll. It also provides a degree of redundancy for when M5 is jammed past Cribbs.
All of that could be provided with a semi-freeflow teardop like M4 J19 (well, M4 traffic couldn't turn around but it could avoid the booths via the M49). The real reason I suspect is the depot access, which is really a crap reason for connecting two motorways with a roundabout.
Last edited by jackal on Fri Jun 25, 2021 13:27, edited 1 time in total.
jackal wrote: ↑Fri Jun 25, 2021 07:21I already said the M49 northern terminus is inadequate. The optimum situation would be a freeflow junction there but with the road otherwise as built. I really don't see why you're objecting to this.
IIRC it was built as a full roundabout to allow traffic on M4 to turn around before the toll booths if they didn't have the money for the toll. It also provides a degree of redundancy for when M5 is jammed past Cribbs.
All of that could be provided with a semi-freeflow teardop like M4 J19 (well, M4 traffic couldn't turn around but it could avoid the booths via the M49). The real reason I suspect is the depot access, which is really a crap reason for connecting two roundabouts with a motorway.
Oh, no, depot access is all that matters... see M3 J9's proposals!
Bryn Terminally cynical, unimpressed, and nearly Middle Age already. She said life was like a motorway; dull, grey, and long.
