I can't speak for Colin, but my take on this is that most roads (and pretty well all roads built post-WWII) were designed and built for cars. Whether they should have been designed and built for cars is another matter. And that doesn't mean other road users are not entitled to use them. But I don't see how you can dispute the notion that they were designed and built with cars in mind. And because bicycle lanes were not in the original design, adding them is retrofitting, by definition.
Sorry I haven't been able to respond to this thread sooner and may well be off topic, again.
My view remains the same. That roads are for people. They are not specifically for any form of transport. My view is that the roads have been built to 'accommodate' motor vehicles, NOT 'designed' for (there's a big difference), and as you have have said, NOT to the exclusion of other forms of road transport. Why do we need bike lanes I ask you? Painted lines on the roads protect you do they? Like I said, it's the piss poor attitude of motorists that drive such measures. And then they whinge about reduced road space because of bike lanes. Many of which are entirely unsuitable for their intended use and sometimes downright dangerous to use or ironically full of parked MOTOR VEHICLES! There's NO reason why we can't all share the roads without the need for bike lanes.Except the piss poor attitude of motorists. Segregated infrastructure only serves to reinforce and justify the piss poor attitude of motorists. Some of whom have already written to the media and expressed their 'opinion' that cyclists shouldn't be allowed to ride on ANY road without bike lanes. Well, how about the opposite? Motorists shouldn't be allowed to use any road without bike lanes? But no, all of a sudden I'm the evil one who is being unreasonable! Funny how things only work one way and people don't like it when their own ideas are applied to themselves.
And what exactly do the motoring lobbyists means by 'designed' for motor vehicles anyway? Your little Madza 3 or massive 4x4s? Motorists seem to think the roads are 'designed' for whatever vehicle they choose to drive at the time, no matter how big or stupidly unsuitable for the road it happens to be. I was almost hit by a Winnebago while riding between Emerald and Monbulk in The Dandenongs a while back. Narrow, winding mountain roads. Hardly 'designed' for such a vehicle. What about the caravans? The grey nomads who like to complain about cyclists on their caravan forums whilst they tow around caravans that don't even fit into their lane on the roads and expect others to make allowances for them.