Comment 116097

By mdrejhon (registered) - website | Posted January 16, 2016 at 19:35:02 in reply to Comment 116020

I am observing a phenomenon every morning when I'm choosing to drive the car to Aldershot GO (...given the still-limited Hamilton GO train departures centrally...)

When I look on the opposite side of the 403, I see a backup of cars on 403 trying to get onto Main St to head into downtown. That's a long lineup of cars, with the offramp (Southwards 403 onto Main) being almost like a parking lot.

We need to re-engineer that somehow. Main St. has a lot of empty space between huge platoons of cars, so in theory certain re-engineering scenarios might simultaneously slow down cars, narrow Main to 4 lanes, AND increase capacity. But there would need to be more visible/safer merge from 403 onto Main, as that 403-offramp merge before Main-Dundurn is a bottleneck, with many cars cutting diagonally across Main to try to turn right onto Dundurn.

It's a really tough traffic engineering problem that works against making the BIA alive, and impacts safety of 403 given stalled cars on the offramp back up all the way into the slow lane of the 403, with cars speeding (in fast lane) past literally stopped cars (in slow lane). Doesn't look particularly safe. Now, anecdotally, Main isn't that busy so there appears to be a bottleneck (e.g. Dundurn-Main)

But patterns show room for optimization.

I see plenty of room in the far lanes (e.g. leftmost lane and rightmost lane) with most traffic fighting for one of the central lanes. But there's empty capacity here and there, and there's tons of empty space between the synchronized-traffilight-surges of car platoons, which can be used as a capacity-speed tradeoff (in order to empty the 403 offramp faster as well)

One theoretical scenario is a solution comes up to get the cars quickly off 403, but slow them down on Main by filling the empty gaps between platoons (caused by traffic light synchronization). And eliminating a traffic lane by adding bumpouts or other buffer zone away from the telephone poles/etc. You'd still get the usual 3 dense traffic lanes, but prevent scattered cars racing on the far lanes (which is dangerous anyway, and should only be parking/turning lanes). Cars merging back into the central lanes from the far lanes (Because they got blocked by a turning cars) consequently slow down cars behind them.

There are traffic engineering tweaks that could execute a compromise of executing a slight offramp capacity increase in exchange for slowing the cars "consistently" elsewhere (tradeoff of emptying the onramp faster but slowing cars down through Main) while improving conditions that could later bring back a BIA. It will still be very arterial 1-way street, but more consistent flowing with less empty space between platoons, and crossings can be highly zebra-marked crosswalks covering only three or four lanes (the lanes that are actually in dense in practice) instead five lanes, at curb bumpouts on the far side of intersection, keeping parts of the curbside lanes on near side of intersection free for turning lanes). You'd have buffer space for pedestrians and possibly wider sidewalks as parking lanes would need less space, etc.

Maybe not that exact scenario, but it looks like it could be optimized, while improving total car-holding capacity (albiet while reducing car-speed) -- basically consistent flow of slower cars (higher density) rather than platoon-empty-surgey of speeding cars (lower density) as a capacity compromise in achieving the narrowing of Main (3-lane 1-way + 2 parking lanes + bumpouts + widersidewalks + shorter crosswalk distances) and/or making 2-way feasible, etc.

Computer-based traffic simulation of various scenarios will be needed to see what fixes can be done here.

Comment edited by mdrejhon on 2016-01-16 19:43:41

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