Some analysis:
AM vs PM
It's worth noting a distinct pattern, particularly noticeable in Bronze routes, where the PM peak frequency is lower than the AM. I'm not entirely sure why this is -- it may be that the PM peak stretches longer, so you don't have as high a demand at any given moment. But regardless, I did opt to include routes that had high-frequency peak in the AM only, but I marked them with a superscript ª.
Gold Line network
These route fall into three categories: radial, circumferential, and cumulative. The vast majority of the network are radial routes (with a few routes in the "Dorchester lattice" that are somewhat hybrid). Most of the radial corridors are familiar, with many being current or former candidates for rail service of some kind. Nearly all of them are feeder services that hook into a rail line, mostly at Harvard, Kenmore, Ruggles, and Forest Hills.
There are only a couple of circumferential routes: the 1, the 66 and debatably the 22 and 31. I'd say the most notable thing about the circumferential routes is how few of them there are -- more on that below.
Cumulative Corridors
There are about a half-dozen cumulative corridors, depending how you count them. The most well-known of these is probably the Roslindale Village-Forest Hills segment, and then the Nubian-Ruggles zigzag. Then you have three little odd segments to the north: a 1-mile stretch running into Lechmere, a Union-Sullivan segment, and then a Wellington-Everrett segment. These are all pretty clearly "accidental" corridors that arise naturally out of major bus hubs. Finally, you have a stretch from Kenmore to Nubian that could/should/may have consistently high frequency service all day; this segment is tricky to map, however, because no route actually runs all the way through from Kenmore to Nubian via Roxbury Crossing: the 8 and 19 come close, but they travel via Melnea Cass rather than Tremont + Malcolm X.
No Gold In These Here Hills
Now, one thing that is notable about the Gold Line network are the places where it
doesn't exist. There's a very clear diagonal axis running roughly from Davis to Andrew: north of this axis, there are almost no Gold Line routes, except for three "accidental" cumulative corridors, and then two corridors serving Chelsea.
No single route out of Sullivan, Wellington, Malden, Lechmere, Wonderland, and only two out of Maverick, reach Gold status. I think I was most surprised to see the absence in Somerville and Everett, both communities that have made several moves in recent years to become more actively pro-transit. I was also very surprised that none of the North Shore routes made the cut, even in cumulative form -- more on that below.
I'm not saying that this is a bad thing necessarily -- all-day high-frequencies may not be warranted in those areas. But it was still surprising.
Notably High Frequencies
There are five Gold routes that I marked with an asterisk to indicate notably high frequencies -- all-day better-than-10-min, or 6-min-or-better at any one time: the 15, 23, 31, 57/57A, and 73. The 15 and 23 were unsurprising, and both hit 6-min during the AM peak. The 57/57A combo was also not particularly surprising, given that it's one of the few corridors where the T actively schedules two routes on top of each other.
The 31 was interesting, though -- from what I can see, it is the most consistently high frequency service on the entire network, advertised at 8-min headways all day. The 31 is also unusual among Gold routes in that it is not designated as a Key Bus Route.
And, for all the talk of Belmont not being friendly to transit, it's worth noting that Waverly enjoys
the highest frequency Gold route, and one of the highest peak frequency routes in
the entire system: the 73 operates at 6-min AM peak, 15-min-midday, and
5-min PM peak. (Yes, 15-min is a bit high for a Gold route, but my standards are lower in the suburbs.) And though it travels through Watertown and Cambridge as well, the
73's Better Bus Profile reveals consistent ridership across the route, if anything skewed slightly toward Belmont.
The Pandemic
It's also worth highlighting three routes whose Gold status has shifted during the pandemic.
The 39 previously operated at 7-min/12-min/9-min headways, akin to its bustitution sister the 57. Currently, however, its midday frequency has dropped to 15-min. Strictly speaking, that should have knocked it out of Gold using the standards I imposed for that area (which cap mid-day frequency at 13-min). However, given the historical precedent, and given that 7/15/9 isn't
that far off from the 8.5/14/8.5 of the Red Line branches, I opted to keep it Gold.
The 93 previously operated at 8-min/16-min/8-min. When I started this project, prior to the pandemic, I tentatively categorized it as "barely Gold" -- those peak headways are good, and like the current 39, the off-peak isn't too far off from the Red Line's branches. However, today the 93's midday frequency is 20-min, though its peak frequency of 8-min is maintained. However, I felt that was a bridge too far, and it got shifted to Bronze.
Finally, the 111, which historically has been at better-than-10-min headways all day, now has its midday frequencies reduced to 18 minutes. This seems... odd to me. Given the historical frequencies, I've kept it as Gold.
Bronze Line network
This is the more interesting part of the map, in my opinion. If you switch on the Bronze layer after looking at the map with just the Gold layer, you'll notice several gaps getting filled in, and it starts to look something like what we'd expect a map of "major" bus routes would look like. These routes fall into a more diverse range of categories, and I'll go through them one by one.
Local "One-Seaters"
These are routes which I suspect often represent the entirety of the typical commuter's journey. These include the aforementioned Southie network (which offers a northern route to downtown via the Seaport, a middle route to Copley, and a southern route to downtown), the 93, and -- debatably -- the 65, which strikes me as mainly being useful for commuting to Longwood from Brighton and Brookline.
Radial Feeders
These are routes whose primary purpose appears to be bringing local passengers to rail hubs to continue their journey into Boston. This map reveals about half-a-dozen such hubs -- and again, it's surprising what makes the list:
Quincy Center
One of the visually tidiest parts of the map, Quincy Center has high(ish) frequency from the 225, high AM but not PM frequency on the 214 and 216 (although theoretically those two could be scheduled to provide all-day high-service on their shared segment), and then cumulatively high frequency peak service to Bicknell Square in Weymouth on the 220 + 222, which do appear to be timetabled together to form such service.
Forest Hills
Alongside the four Gold corridors, the 34/34E combination creates another borderline case. In theory, the dual 30-min headways of the two routes during midday
should result in 15-min headways or better all day, which would mark this as a Gold route along the shared segment. However, the midday spacing is uneven and has some pretty long gaps, so I didn't feel it quite cleared the bar. It is notable, however, that the 34 is advertised as having 10 or 11-min headways during the peak, which on its own would merit inclusion as a Bronze Line; the addition of the 20-min 34E at peak is an interesting supplement. (Also, the printed timetable for this route is
terrible at highlighting the frequencies along the shared stretch.)
Davis
A dubious contender on this list, Davis has no individual radial Bronze routes feeding into it. (I'd argue that the 89 is more of a circumferential route.) However, College Ave up to Winthrop Street shares the 94 and the 96, which theoretically could accumulate to 10-min headways in the AM peak. There's a really interesting topology of other routes that overlap this and neighboring corridors, including the 80, 89 and the 95, which is an example of a theme that's repeated elsewhere -- some areas have lots of routes, but because they need to cover so many permutations, it's much harder to treat their overlap as cumulative. And obviously, the opening of GLX will see a compete rework of this quadrant of the network.
Sullivan
An interesting array here. The aforementioned 93 boards some 20% of its inbound riders here -- the
Better Bus Profile notes that these are individuals returning to their residences along Bunker Hill Street, so at this end it behaves more like a radial feeder than a local one-seater. The 89 is a bit of a hybrid of radial feeder and circumferential. The combo of the 104 + 109 to Everett is well-known at this point, thanks to Everett's bus lane efforts. But the one that surprised me was the 101, which runs a triangular route between Sullivan and Malden via Medford at 12-min peak headways. That's not a route that's on my radar much, though I can definitely see its usefulness.
(If memory serves, bus lanes on Broadway in Somerville are coming, which would be great since both the 101 and 89 run at 10-12 min headways at peak. Off-peak, they both drop to 30-min; in theory, these could coordinate to provide all-day 15-min-or-better service along Broadway, but if I recall correctly their current schedules produce too many gaps in the midday to reach Gold status.)
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