Quote:
Originally Posted by 93JC
Why? Let's just say for the sake of argument that the equivalent road is three times as wide as the transitway. Trenching/tunnelling the road is therefore three times as expensive as trenching/tunnelling the transitway, itself a pretty expensive proposition in the first place. Assuming we buried this hypothetical road in a tunnel then you also have to account for the substantially larger ventilation system required to keep the air in the tunnel breathable. I fail to see how "on balance" that would be "better off".
I understand that it would make the experience for the transit users 'nicer', in that they'd have some scenery to look at and by contrast it shouldn't really matter to the drivers on the road because they should be looking at the road while they drive instead of sightseeing along the way, but you'd be spending an enormous amount of money to make the transit users experience 'prettier'. That's a pretty hard sell to a cash-strapped municipal government. |
I was also thinking in terms of the relative effects on the urban fabric and how it can be crossed. An at-grade 6-lane road doesn't do much for pedestrian, cycling and other local traffic circulation. If it's an expressway, you often end up having to climb up and over; that's bad enough for pedestrians but for cars it means having embankments extending some distance from the expressway. The other option is to go under, which can also be pretty obnoxious.
But if the expressway is sunk in a trench, then the local road network can more-or-less go over it without grade changes. You've got an example of that at Elbow Drive and Glenbow Trail.
In addition, road tolling may well be an easier "sell" for sunken or tunnelled expressways.
In new suburban areas, sinking roads can be accomplished at somewhat less expense. The very nature of modern suburban land development tends to raise grades anyway (basements replace soil, which is piled up around houses, and streets are dug out and filled with gravel and pipes, the soil becoming surplus), so one could split the difference: partly sink major roads, and partly raise local roads over them.
On the other side, with light rail running at grade, it's generally not that difficult to cross (especially if it is in its own RoW) since vehicle movement is generally not so frequent as to make grade crossings problematic and it has a visibility to the public-at-large that sunken systems don't have. Until the vegetation was hacked back recently, the Transitway trench here in Ottawa along Scott Street was largely screened; if it weren't for the ridiculous chainlink fencing it'd be even harder to see. Here's where the vegetation is still in place, and if you know to look you can guess where the Transitway is:
http://maps.google.ca/maps?f=q&hl=en&geo...Jr--wxSQzwCMFSthw&cbp=12,328.46,,0,13.52
But it's not "visible". You won't see rapid transit vehicles going across from up the street to the south. The nearby station itself looks a bit like a bunker and it's not too obvious what its function is:
http://maps.google.ca/maps?f=q&hl=en&geo...aXcbx5s5Kn_gensidUQtgw&cbp=12,22.63,,0,2
You won't see a train stopped in the station nor people waiting for a train as you drive by. It's there, but not really there. It amazes me to this day how few Ottawans are aware of where the Transitway actually runs because we've succeeded in putting it "out of sight, out of mind". That piece of Transitway alignment once was a railway and we should have built a light rail line at grade along it rather than trenching a busway.
So I wasn't really thinking about it in monetary terms, but rather the way it all works with its surroundings. And by that metric, sinking major roads makes more sense than sinking things like light rail lines.
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