First of all, it really should go without saying that seconds matter when building transit. The entire premise for infrasturuce upgrades is that it'll save commuters a few minutes. Well guess what: seconds quickly turn into minutes. A politician might proclaim that a new subway line will save commuters 5 minutes. But when you consider that headways for this project might be 2 minutes less frequent than what it replaced, then you consider that commuters will have to spend 60 seconds on escalators both when entering and leaving a station, and then consider that they might have to spend another 45 seconds navigating the concourse levels, that 5 minute in savings is now a meagre 15 seconds.
This was one of the many fatal flaws of the SmartTrack plan, for example. Yes, the in-vehicle times were significantly faster. But once waiting times, walking times and burdonsome transfers were considered, the proposed plan was, in many cases, only nominally faster than what existed today.
Seconds matter.
The magnitude of the difference depends on what we're comparing to.
If we're comparing to the LRT plan, we're probably talking a difference around 15 seconds. Which was precisely my point. We're spending somewhere in excess of $3.5 Billion to give people a transfer that is no better than the LRT plan (or perhaps even the existing SRT transfer), while decreasing rapid transit coverage across Scarborough and lengthening commute times due to the loss of several rapid transit stations. This feels like one step forward, two steps back.
If we're comparing Scarborough Centre Station to the "idealized" Toronto transfer - one with a short walk and short vertical elevations - the difference is likely on the order of several minutes.
Here are two free papers on the matter:
https://dspace.mit.edu/bitstream/handle/1721.1/66798/52971233-MIT.pdf?sequence=2
http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.592.1822&rep=rep1&type=pdf
From the second paper:
"Given that travelers tend to consider out-of-vehicle travel time (walking, waiting, transferring, etc.) to be substantially more burdensome than in-vehicle travel time, attracting travelers to public transit in significant numbers requires transit agencies to focus increasingly on improving transit users’ experience outside of their vehicles – walking, waiting, and transferring."
As an example, lets say someone has two possible routes to take to their trip: One takes 15 minutes with no transfer, and the other takes 11 minutes with one transfer. In this case, the person would be more likely to take the 15 minute trip over the 11 minute trip, because they perceive that transfer to take longer than it really is.
"Physical aspects of transfer facilities can also affect walking time to travel between locations where people alight and board vehicles for transferring. Such aspects can also influence travelers’ experiences at facilities, and therefore their perceptions of waiting time, walking time, and transfer penalties. "
This point is particularly problematic for both the Relief Line and Scarborough Subway Extension (and even the Eglinton Crosstown), due to the incredible depths of those lines. Both projects will be at least 20 metres deep. Consider that it takes
73 seconds to travel a vertical elevation of 20 metres. Due to people's perception of time out of vehicle, they'd likely estimate this to take more than a minute and a half. And 73 seconds does not take into account time spent navigating the various concourse levels, time to get from the train to the escalator or time penalties due to rush hour congestion. Furthermore, not everyone is physically healthy, further deterring people from making the trip. This is particularly relevant with our aging population - I know my grandmother would (justifiably) balk at the idea of climbing a vertical elevation of 20 metres.
This is actually even more problematic for the Relief Line than the SSE. If all Relief Line Stations are 20 metres underground, commuters will be spending a whopping 146 seconds on escalators. This'll kill much of the utility of the Relief Line. If you don't believe me, you can look at some of the more recent Relief Line ridership reports. In those reports, you'll see how an added trip time of a minute or two caused usage of the line to drop by something like 20 to 30 percent (again, seconds matter). Assuming there is no safety issues, I'd much rather put these lines shallower; vibrations be damned.