Streetcars and buses both operate on city streets, in similar ways. So why go to the trouble and expense of building streetcars? Because there are, in fact, inherent differences that make one or the other better, depending on circumstances.
First, what’s not an inherent difference: The running way. Both streetcars and buses can, should, and do operate in both dedicated lanes and in mixed traffic with cars. When and where they do so can make a huge difference to a line’s effectiveness, but that decision is not dependent on the vehicle. The point of this list is to compare the modes when all other things are equal.
- Streetcars have greater capacity than buses. Streetcars are bigger, longer, and can be combined into multi-car trains. They can carry many more passengers than any bus, even accordion buses. For corridors with ridership too high for buses to handle comfortably but not high enough to justify a subway, streetcars can be a good solution.
- Streetcars can be more affordable than buses over the long term. While it’s true that streetcars cost more to build up front, that cost can be offset by operational savings year-to year, if the line carries enough passengers. Streetcars’ higher capacity means if there are lots of riders on a route, you can move them with fewer vehicles. Fewer vehicles means more efficient use of fuel and fewer (unionized and pensioned) drivers to pay. Streetcar vehicles themselves are also sturdier than buses, and last decades longer. In the long term, streetcars can be more affordable on very high ridership routes.
- Streetcar tracks reassure riders they’re on the right route. In any big city, buses are confusing. There are so many crisscrossing routes that buses are intimidating and difficult to understand. For example, DC’S 16th Street has no fewer than 5 different routes, with two of them labelled identically as the S2 despite different destinations. New users are turned off because they don’t want to accidentally get on the wrong bus and end up far from their real destination. Since streetcars have to stay on their tracks, streetcars reassure riders their vehicle will go where they want it to go.
- Streetcars stand out. The fact that streetcars are expensive to build means cities can’t realistically put them on every route. The size of any streetcar system is therefore inherently limited to only the more important routes (though how a city defines “important” may vary). This provides a convenient proxy for people to know where the best transit routes are, since most people don’t memorize their entire region’s incomprehensible jumble of bus routes. Instead of that jumble, streetcars provide a simple system map that’s easy to memorize. Meanwhile, trains are also civic icons. Tourists visit them, photograph them, and send postcards featuring them, all of which enhances a city’s brand. It’s true that frequent route networks and unique branding can bring some of these same benefits to buses, but streetcars are more powerful and noticeable symbols.
- Streetcars are more comfortable to ride than buses. Any vehicle running on large tires over asphalt will sometimes be a bumpy ride, especially if the pavement is in less than perfect condition. Gliding along a rail is inherently smoother, making for a vastly more comfortable ride. This issue isn’t often discussed in newspaper articles, and rail opponents like to pretend it’s not a big deal, but it matters. And it’s not strictly a luxury issue, there’s a practical benefit: A smoother ride means passengers are more willing to stand, allowing for more open railcar interiors that maximize capacity.
- Streetcars are economic development magnets. The presence of rail transit nearby is one of the best incentives for economic development in the world. Metro stations radically remade large swaths of the DC area, and streetcars can do the same (have done the same, in places like Portland and Toronto). Developers rarely base decisions around bus lines, but routinely follow rail investments with real estate ones. In fact, the additional taxes generated by rail-oriented development is often used to repay the initial capital investment of rail lines.
- Streetcars are quieter and cleaner than buses. Because they run on electricity, streetcars are very quiet and emit no vehicle exhaust. While it’s true that electric trolleybuses exist, they are almost never used in the US because of BRT creep, and no new US city has introduced them in generations. This isn’t a truly inherent difference, and it may disappear as wireless electric buses proliferate. But for the time being it’s a legitimate difference.
- Streetcars are sometimes faster than buses. Most streetcars have at least 3 doors, and many models have 4 or more. That means passengers at stations can load and unload faster, meaning streetcars can spend more time actually moving, and less time dwelling at stations waiting for passengers. Thus, when streetcars are not held up by other traffic, they’re faster than buses.
- Streetcars attract more riders than buses. For all these reasons, people who would never consider riding a bus will ride a streetcar. Operational details trump all else, but when every other detail is equal, rail attracts more riders.
Of course, buses are useful tools too, and are the right choice in many (in fact most) situations. Buses must be a major part of every city’s transit network, including both local and rapid bus routes. But buses are demonstrably different than streetcars. They have different characteristics, accomplish different goals, and are more appropriate in different places.
- Buses are usually cheaper. Buses don’t require the huge initial construction cost of streetcars, and except on the highest-ridership routes buses are generally cheaper to operate. This fact alone means buses are the right choice for most routes.
- Buses can put more service in more places. Since buses are generally cheaper, a city can provide good transit service on several routes, going to several destinations, for the same cost as comparably-frequent service on one streetcar line. This is why every city in America uses buses instead of streetcars for most of its routes, and only introduces streetcars at special locations.
- Buses are more flexible. Streetcars must run on rails, which sets their routes in stone. That’s both a blessing a curse. While it means riders will always know where a route goes, it also means branching routes are impractical, which limits how broad an area transit can cover. Buses give transit operators the ability to send some buses that start off on the same route to different locations, such as how DC’s S2 and S4 Metrobuses split near Silver Spring.
- Buses can skip ahead. On any street with more than one traffic lane, buses can pull around obstacles and speed forward. Streetcars must wait for obstacles to clear, meaning buses in mixed traffic with cars are often faster than streetcars in similar mixed traffic. It also means express and limited-stop bus routes can operate on the same streets as routes that make all stops. Technically speaking this isn’t an inherent difference, since a streetcar line could be built with multiple parallel tracks and frequent crossovers, but practically speaking that never happens.