(cover photo credit @sg5921y who also came up with this debunk-able line today)
A post I decided to write on a whim, and consider this an introductory post to a subsequent one about total travel times.
With Tower Transit gradually taking over the Sembawang-Yishun Package (a.k.a. SYBP or MDDEP) in tranches (i.e. sections of the bus package that TTS receives one at a time, again to space out the transition), there have been mixed feelings and a fair bit of controversy regarding the SYBP transition, probably because (1) the large number of “popular” routes involved in this package (e.g. 858, 969), and (2) the community had pretty much understood what BCM was about, after being familiarised of the process in the previous 4 packages (Bulim, Loyang, Seletar, Ulu Pandan), and for the first time we witness supporters and detractors of the outgoing and incoming operators (SMRT and TTS respectively) launching rather heated debate defending their own sides. (Of course, you guys know which side I’m on: The side of good bus service. Am leaving this to your own intepretation.)
So anyways, a common feature of those debates would be to find evidence to support their preferred operator, and while most of that is just superficial fluff unrelated to bus operations (I’m quite disappointed in the bus community nowadays, who mostly support or hate operators based on things entirely unrelated to bus operations, do they not know what the main purpose of bus operators are?), some actually cut to the heart of the matter, one of which I’ll feature below.
On to today’s showpiece…
Side Tower Transit, the floor is open, please.
[edited into full, proper statements, from whatsapp debating]
Tower Transit has quickened runtime on Service 965 by 8 minutes from the original SMRT scheduling of the service.
SG5921Y
Of course, he left no conclusion to that statement (should have gotten him disqualified in a normal debate, but in the bus comm and on Whatsapp, rules of cordiality and decorum don’t apply), but from the statement the logical conclusion should be dead obvious: that Tower Transit’s arrival in Mandai brought about a service improvement. Seems fine, right?
Not so fast!
Yes, the schedule has been improved by 8 minutes. What wasn’t specified, though, was that the shortening of travel time by 8 minutes, was for the full trip (as usually is the claim that TTS supporters make when they advertise supposed speed improvements under SYBP). For service 965 specifically mentioned here, that would mean a full trip from Woodlands to Sengkang, and then back to Woodlands again (tidbit: some trunk and long feeder routes loop at the non-anchor interchange, so the BC doesn’t have to alight and risk getting infected by COVID.) In the context of such a long journey, 8 minutes… seems rather trivial. (Admittedly I don’t know whether by full trip the claimant meant one-way to Sengkang only or both ways back due to the complexity introduced by the loop, but I’ll give benefit of doubt and assume that indeed there was an 8 minute improvement for the one-way trip, or 16 mins shaved for the entire journey to Sengkang and back.)
Thus, for you to enjoy this full 8 minute reduction in travel time viscerally you’d have to be a regular commuter on the full trip of Service 965, from Woodlands all the way to Sengkang! Otherwise, your travel time improvement will only be the fraction of line length you travel times this supposed eight minute benefit! (eg if you only ride a quarter the line length, your travel time reduction is only 1/4 x 8 min = 2 minutes, assuming uniform travel time reduction across the line)
Take our 965, for instance. The main flaw in the line of logic that was perpetuated above, is that hardly anyone in their right state of mind would be riding the full length of 965 (spoiler: no one does) and thus there will not be a single person to experience this theoretical “8 minute reduction” in travel time!
For 965, most of the “longer” trips (i.e. we discount the types that only ride two or so stops) fall into two categories: between Woodlands East/Yishun North and Yishun MRT, and between Yishun MRT/Yishun South to Sengkang (and in the opposite direction too). At this point it’s getting rather obvious where this is going: one is a minority section of service 965’s route (length-wise), and one, while more than half the route length, isn’t more than half by much either.
Woodlands East – Yishun: 5.85km (27.59% please casually ignore my inability to do sf)
Yishun – Sengkang: 13.9km (65.57%)
Therefore for the large majority who ride 965 at these sections only, their actual time savings (based off 8 min travel time reduction for full journey) would be:
Woodlands East – Yishun: 2 min 12 sec
Yishun – Sengkang: 5 min 15 sec
For those who ride only a few stops in a row, the IVTT reduction would be negligible! Really don’t see why there is so much fuss kicked up over this, and the “8 min” statement is very, very misleading!
And of course for the above calculations I have made the gross statistical error (that will send practical mathematicians flying into the stratosphere in their fit of rage) of assuming uniform travel time improvements across the entire route, which of course isn’t the case. Actual travel time improvements thus may be wildly different from what I calculated too, wow! (ew)
When you couple the (now insignificant) travel time improvements with a guttered frequency (what, you expected altruism when they upgraded the fleet to DD?), your net travel time may… be worse off than before! (surprise surprise shock shock!) Yes, you have your 2 min travel time reduction. And then, voila, TTS proceeds to lengthen the bus interval by 5-10 minutes on the grounds that “a full DD fleet will do the trick”. (angery face)
A 2 min trip time reduction, and then a 5 minute increase in waiting time, well, there’s still a net increase in overall trip time, thus leaving you worse off than before!
The next time someone comes up with the claim that TTS (or any operator) improved bus service by “improving runtime” by a certain number of minutes, remember: they are always talking about full-journey improvements, not improvements for partial trips!
Tower Transit’s entry into Mandai was not an improvement to bus service in northern Singapore. I rest my case.
Myth busted: Shorter runtime =!= shorter overall trip time
Liked this article? Sub, like and share this post, to spread the love around! E:3
SG Transport Critic 
4 thoughts on “Mythbusters – “runtime improvement”?”