Reading design guidelines for bus routes reminds me of how different surface transit is from rapid transit. Buses need to follow straight, wide, two-way roads. Subway trains do not: those roads make construction easier, but it’s normal for train lines to detour and turn, even in rigidly gridded cities like New York. The upshot is that sometimes the optimal route for a bus is different from that of a subway, and this limits the usefulness of preexisting bus routes for subway planning.
For a relatively simple example of this, consider the plans for a subway under Wilshire Boulevard in Los Angeles. The buses follow Wilshire all the way from Downtown to Santa Monica. The trains were never intended to: there’s a short stretch where Wilshire isn’t as important while somewhat off the street lies Century City, and all alignments studied for the Wilshire subway have involved some deviation. The chosen alignment is the one that deviates more than the other, to serve Century City more centrally.
This is relevant specifically to the example of Tel Aviv. When I criticized the Tel Aviv subway route choice for being politically motivated to avoid certain neighborhoods, Alan of Tel Aviv Bus Mappa said,
To minimise cost, the planners looked at what works today (the existing high-demand bus routes) and decided that connecting Petah Tikva and Bat Yam to Tel Aviv was the highest demand corridor. They also looked at what was wide (boulevards and arterials), as their aim was to maximise segregated on-street running. This is also the reason that the plan makes use of the ‘Turkish line’ alignment connecting Jaffa and Allenby rather than the more direct, but narrow, Derech Yafo and Eilat Street.
Central Bus Station would have been a huge diversion for the route and is not a particularly in-demand destination. However, the planned Green line will serve that location.
The problem with this line of thought is that subways are not buses. Subways can use the more direct but narrower alignments if they need to: it may be somewhat more expensive to construct, but there’s no disutility to passengers. A bus running on a narrow street is slowed down, especially if the street is twisty. A subway that can go under private property is not.
Even in New York there are some twists – for examples, the route of the L through Brooklyn, and the route of the 2/3 from the Upper West Side to Harlem. But those twists are not critical, and the city doesn’t really need them. The Wilshire deviation in Los Angeles is also in this category.
It’s ungridded cities where the ability of trains to cut under the street network becomes critical to providing service to major destinations, which may not be anywhere near the wide streets. A look at the inner network of the London Underground will confirm that the lines bear little relationship to the street network, which was built incrementally over the centuries and would not be good at serving the major destinations in the desired directions. In Paris the older lines were built subsurface and do follow streets (which at any case are more rationalized than in London due to heavyhanded central planning), but the newer ones were built deeper and do not.
In Tel Aviv, the problem is that many of the neighborhoods that need public transportation service the most do not have wide streets for buses, or have wide streets configured in the wrong directions. The oldest parts of the city, the Old City of Jaffa and Ajami, have very narrow streets since they predate modern boulevard design by a few centuries. The next oldest – the Jewish neighborhoods of Jaffa, South Tel Aviv, the western parts of Central Tel Aviv, and the Old North – do have wide streets, but often pointing in the wrong direction, for examples nothing serves the Port or the Basel Heights compound, and the east-west streets going through the Old North are very narrow. They have no reason to form a coherent rapid transit network, since they were built as interurban streets or as neighborhood main streets, not as subway alignments. They barely even form a coherent bus network, but the hacks made over the decades to create bus trunk lines are different from the optimal route a subway would follow.
In fact, the recently-reelected Huldai administration has plans to upzone around the central parts of the route to build a new CBD. The area in question, around Begin Road, is unwalkable and almost unfixable to be made pedestrian-friendly, the road is so wide and fast. This is not service to an existing destination that follows a linear corridor as in New York and other strongly gridded cities.
In a city like Tel Aviv – or any other city without a strong grid that influences development – subway planning should start from a list of major destinations and dense residential neighborhoods and their locations on a map. The subway routes should form somewhat straight lines connecting them, with the first line chosen in a way that connects to the most and the most important ones. It’s fine to have somewhat kinked routes – nobody likes riding a C-shaped route, but it’s okay to have small deviations such as the ones proposed for Wilshire or even larger ones such as the one Shanghai’s Line 1 takes to reach People’s Square. The junctions should be the most important destinations, or the ones with the most potential for CBD formation; in Tel Aviv those are generally to the west of the planned CBD, because of the potential for waterfront upzoning and the preexisting density in the neighborhoods south of the Yarkon and west of the Ayalon Freeway.
Buses are of course not planned like this. A city that wants a vigorous bus network needs to do what Los Angeles and Vancouver have done: put the buses on a grid as much as possible, and have them go straight along major roads, with as few deviations as possible. Vancouver’s north-south buses deviate a little bit to serve Downtown, and even those deviations are sometimes questionable since people transfer from the buses to SkyTrain before the buses reach Downtown. The grid allows for an efficient network of transfers, with the transfer penalty reduced by high frequency on the trunk lines. It’s nothing like subway lines, which form a tight bus-like mesh in about one city in the world (Mexico City) and everywhere else have a mesh-like core surrounded by what is an essentially hub-and-spoke system.
Even when the busiest bus routes do indicate something about subway demand, there are exceptions. In New York, the busiest bus lines today are the M15, on First and Second Avenues, and the B46, on Utica Avenue: they are almost even in ridership and have traded places for first place citywide recently. But nobody expects a Utica subway to get the ridership of Second Avenue Subway, even people like myself who believe such a subway is underrated and should be considered in medium-term transit planning. The third busiest route in New York is the Bx12, on Fordham, and I do not know a single transit activist who believes it should be railstituted, even ones who believe other routes with somewhat lower ridership should be railstituted (such as Nostrand, whose bus, the B44, ranks fifth). The issue here is that First and Second are in Manhattan, where bus speeds are so low that ridership is suppressed, as people walk longer distances to the parallel subway or don’t take the trip; if both Second and Utica get subways, the lower amount of congestion in outer Brooklyn is irrelevant and the trains will travel at the same speed, whereas today there are factors working against Second that make the rail bias there higher than on Utica.
Something similar is the case in Tel Aviv. The widest boulevards have the largest concentrations of bus trunk lines, but that’s because they are the only streets on which buses are even remotely feasible as modes of transportation. In Jaffa, Jerusalem Boulevard is wide enough for fast surface transit but Yefet Street is not. Based on Jerusalem’s width, the planners chose to keep trains at-grade on Jerusalem, which they could not do on Yefet. But if trains were underground, Jerusalem’s current advantage would evaporate, leaving Yefet with the advantages of proximity to the Old City and the Flea Market and of higher density.
It is wrong to plan buses as if they were subways or early-20th century streetcars, where frequent twists were not a problem since there were few cars on the road, and where the dominance of the traditional downtown favored a hub-and-spoke network. Recent bus successes in North America have involved discarding those ideas and planning buses based on modern travel needs and modern traffic levels. By the same token, it is wrong to plan subways as if they were buses when they are capable of following alignments that buses cannot.