Fun fact. It's intended in the long term to abolish Melbourne's 'shield' road route numbering system and replace it with the statewide alphanumerical system.

You can already see this partially underway in the outer western and south-eastern suburbs where alphanumeric routes have been implemented on new/rebuilt roads rather the shield system being extended.

There isn't a funded program to replace the routes en masse, but I understand they've pretty much all been mapped.

In the meantime, when new direction signs are made, they're typically printed with the new alphanumeric route number which is then covered by a plate printed with the pre-existing shield number. These plates can be removed when the new routes are formally rolled out.

I'm not sure if it's been corrected yet, but there's a new sign on Wurundjeri Way directing drivers to Dynon Road with the route number C444, which has not been formally implemented. Dynon Road retains the shield route 50 for now.

The new alphanumerical system will not be a direct replacement for the shield system. Some shield routes are on local council roads and will probably be removed entirely rather than replaced (eg. Somerville Road east of Geelong Road).

Vice versa, some government arterials don't have a pre-existing route number but may get one with the new system.