A heretical transport planning idea

The Freeway south from Perth (the "Kwinana Freeway") currently ends somewhere south-east of Kwinana and north-east of Baldivis. This freeway is part of the highway that runs from Perth south to the boom areas of the WA South West (Bunbury, Busselton, Margaret River etc.) , gets very congested at peak times and is going to be extended in the near future (the "Peel Deviation").

Hugging the freeway all the way down are a number of current and potential urban development areas, including Baldivis, Amarillo and Ravenswood. Obviously, this makes them prime contenders for 'car dependent' suburbs as it will be quick to drive and PT will have a hard time competing (the new Mandurah rail line is too far west of these suburbs).

Here is my 'heretical' idea. It is a given that the freeway will be extended, but how about it be built as a genuine long distance highway? In other words, it should be designed in such a way that it bypasses the urban areas without interchanges. The people of Baldivis and Amarillo would have access to much the same road network as at present (ie be no worse off) but public transport would be given a big fillip by continuing to be time competitive. It would have to be carefully designed so that interchanges could not be retrofitted at some time in the future.

This would require some work to sell, but nothing a good politician shouln't be able to handle!