King County Metro’s Route 48, running from Mount Baker to Loyal Heights via the U-District is the highest-ridership route in the county; it’s also one of the longest routes in Metro’s network that exists entirely within the densely urbanized and heavily-trafficked urban core of Seattle. Both the north and south segments could stand alone as high-performing frequent-service routes: they would be the 8th and 16th highest-ridership routes in the county respectively. It is also, anecdotally, one of the most pathologically unreliable routes in Metro’s network, earning the sobriquet “forty-late” from its riders.
Talk of splitting the 48 in the U-District probably began when the route was created, and has yet to stop. In general, there tends to be much more transit ridership from residential areas to urban centers, or between urban centers, rather than between residential areas. While reasonably good bidirectional demand exists throughout the route, much of the 48’s ridership is going to or from the U-District, and in that circumstance, splitting the route there has the potential to improve reliability for all riders, while forcing only a minority to make a transfer.
There’s a another good reason to split the 48: the south section already runs under trolleybus wire (used by the 4 and 43) for much of its length. Were this bus split, only about 1.5 miles of trolleybus wire would be required, between John and Cherry, and Dearborn and Plum. At the current cost of $3 million per mile for trolleybus wire, electrifying this route would probably cost less than $5 million with minimal construction risk or environmental process entailed. Along with the roughly $12 million project to move the 3/4 wire from James to Yesler, this project would be perfect for the $20 million earmarked for trolleybus expansion in the city’s $60 VLF proposal.
There are two main problems with splitting the 48. In general, splitting a route often increases the number of service hours required to achieve the same amount of service, as the tails of the two routes need to overlap somewhat at the ends, especially in a place like the U-District, where busy stops are spread out over an area with high traffic congestion. The other issue is layover space. Curb space could be obtained in the north end of the U-District fairly easily for the 48S, but nothing is available near Montlake for the 48N. What we really need to make this happen is a suitable through-route partner for the 48N.
It turns out, we have one; or to be more exact, we will likely have one once the 520 is tolled. Currently, the 520 is grossly unreliable for much of the day; dynamic tolling to ensure free-flowing traffic — now expected to start by the end of the year — should fix this problem (not to mention boost transit ridership). The 48N and 271 (as far as Bellevue Transit Center) have comparable service levels and demand, making them an excellent match for a budget-neutral change in through-route. The 271 needs only a few more trips to match the 48’s daytime frequency. On evenings and Sundays, when their schedules do not align so well, layover space in Montlake is less constrained due to the through-route of the 43 and 44.
There’s more to this change than just swapping one set of possible one-seat rides for another: it dramatically improves connectivity between north Seattle and Bellevue, a corridor for which Link will not do much. Riders on the two main routes to north Seattle, the 5 and 358 (future RapidRide E) will have two-seat frequent service rides to Bellevue. As University and North Link build out, the importance of through-trips enabled by the current configuration will diminish. Riders currently using the 48S for long-haul trips to the Rainier Valley will have the much more convenient option of transferring to Central Link.
One change to the Eastside network might be required: either the Bellevue to Issaquah section of the 271 will need to be split off or assigned to another route, or it may be necessary to schedule a five minute hold at Bellevue TC in order to maintain reliability on those trips that extend to Issaquah. This is already done for some midday 271 trips.