Commuting trends: transit vs driving vs ...

[ijmorlan]

I assume you mean rebuilding narrower, as opposed to rebuilding unchanged? I can’t imagine that you would ever rebuild just to lose a tiny bit of width — you would adjust the design when rebuilding anyway.

It seems obvious that rebuilding narrowed should in most cases cost less, so there is no up-front cost, just a small immediate savings, and then small ongoing savings over the years, combined with a small safety increase. The cost is that drivers have to actually watch what their doing and drive at a more reasonable (or less unreasonable) speed.

Correct, at the time of rebuilding.

But is it really less expensive? There is less paving, yes. But it requires new curbs, boulevard repairs, driveway repairs and traffic sign relocations. How much do those cost, as compared to the savings in pavement?

I’m assuming that we’re talking about a reasonably comprehensive rebuild that includes the curbs and sidewalks, not just a repaving of the road itself.

I agree that if the alternative is leaving the existing curbs in place, then it could add expense to move them (out or in).

In a lot of cases though what should be dropped is not a few tens of centimetres but entire lanes that are utterly unneeded. There are many roads around the region that have four lanes with no turn lanes. In almost all cases they would be better as two-lane roads with turn lanes where needed. I’m thinking about Union, Belmont, and streets like that where we are paying for four-lane capacity but not getting the benefits of four-lane capacity (and in any case if the road actually had four-lane-capacity traffic, it would be all jammed up due to the absence of appropriate turn lanes). There are probably even cases where the intersections should actually be bigger than they are (ought to have all possible turn lanes) connected to streets that are excessively wide.