Aidan wrote:Melbourne's A8 keeps its number despite being bypassed by the M8.
No it doesn't. The former route of A8 through Deer Park is now 'Metropolitan Route 8' - completely different to A8. But illogical in itself because Victoria has this hybrid of alpha-numerics and the old shielded routes.
A better example would be Sydney - National Route 1 moved onto the F3, old alignment becomes State Route 83. National Route 31 moved onto the the route of the Hume Hwy, old alignment becomes State Route 89 and so on.
Thirdly, do you also object to it keeping the name Main North Road?
No. However, I think the Northern Expressway should be named and signed as an extension of Sturt Highway.
Nathan wrote:Is there anyone that actually chooses how to get from A to B by the route number of the road?
Regardless of what you think of route numbering, the whole point of having the system is to help stranger drivers navigate. It makes much more sense to end the A32 and encourage use of the M20 to reach Adelaide, rather than imply that Main North Road is actually the major road into Adelaide, which it isn't.
The actual number given to Main North Road does not matter, as long as it is different to the section north of Gawler to reflect the different roles of the two sections.
DM8 wrote:The Northern Connector would make things more interesting (when, or rather *if*, it gets built). Would M20 continue on that also? In that case (and a tad off topic, sorry), I wonder what happens when it hits the South Road Superway?
My preferred option:
- M20 terminates at Port Wakefield Road
- A13 extended along Nothern Connector to Port Wakefield road
- Salsbury Highway renumbered to either A9 or something else.
Rationale:
- Direct connections from M20 and A13 to A1
- Northern Connector is not part of Adelaide-Sydney route, it is moreso part of the South Road corridor and the route numbering shoudl reflect that
- Salisbury Highway is no longer relevant to the majority of A13 traffic to/from the south so it should have its own number
- A9 is a convenient solution but I would be equally happy with a new number as Salisbury Hwy and PRE are two very different routes
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Route marking is quite an undervalued concept - it is an important tool to aid navigation. Furthermore, if it is going to exist at all it should be done properly otherwise the investment is completely wasted.
SA has a reasonable system set up from scratch, however, it takes dedication to maintain the logic in that system. Renumberings like this are often left till the last minute or not budgeted for at all and don't get done - then the system starts to lose its logic.
Great example from Tasmania - when the Guildford-Hampshire line was built c1990 to provide a higher quality route from Burnie to the lower West Coast, it should have been numbered A10 because it is now the main West Coast to Burnie link. Unfortunately - due to opposition from businesses along the 'old' A10 and also budgetary constraints - this wasn't done. Now you have the illogical situation driving up the A10 where the main route actually has a different number and the A10 requires two turns to stay on the route and then takes you along the old low-standard route via the Hellyer Gorge.