If you're a mid-sized metro area whose only form of public transportation is the bus, you might increase transit ridership just by tweaking the system. Lose a stop here, add one there, draw a few new maps. That worked for Broward County, Florida, which recently grew its passenger base by shifting its focus on job centers rather than downtown districts, but what if you're a big city with a major rail system? It's a bit harder for a conductor to steer the subway into another neighborhood.
Big cities that want to increase ridership have a few larger policy options to consider. They might subsidize fares (that is, cover operating expenses that exceed the system's revenue). They might regulate automobile use (say, through congestion pricing or tolling). Or they might expand the rail system that's already in place. These aren't exactly simple efforts—the politics will be tough, the implementation expensive, the outcomes scrutinized—so you better choose wisely.
In an upcoming issue of Transport Policy, a group of Chilean researchers led by Louis de Grange of Diego Portales University investigated these three ideas to see which emerged as most effective. Using data from 41 major cities around the world, de Grange and company ran a total of 16 econometric models comparing these methods. After controlling for key demographics the researchers found a consistent pattern: System expansion increases transit ridership a little. Car regulation increases it a lot. And fare subsidies have no effect at all.
On an average, a 10% extension of a city rail network generates an increase in transit use of almost 3% and a decrease in automobile use of more than 2%.
We further concluded that regulation of automobile use and possession via policies such as road pricing and taxes on car acquisition also have a positive impact on transit patronage. In cities that have implemented effective regulation of this type, the use of cars has dropped by an average of 20–30% while transit use has risen in similar proportions.
Lastly, we found no evidence that fare subsidies encourage the use of transit as an alternative to private cars, corroborating previously published research on the issue.
And here's some of the data the researchers used, which also shows which cities were studied (I believe that first should be Seoul):
It's rare for policies like these to be directly compared, but the results nonetheless square with the specialized lines of study. A 2003 report [PDF] found that a 10 percent rail expansion reduced automobile use by about 4 percent—"the largest effect on driving" of all the variables in that study. Meanwhile older data on toll rings, and more recent data on congestion pricing policies, speak to the ability of those programs to influence mode choice.
Studies about the effectiveness of fare subsidies, meanwhile, have been less conclusive. Some older work cited by De Grange and colleagues found that as transit subsidies increase, productivity declines and costs rise [PDF], and later work concluded that even free public transit wouldn't substantially reduce vehicle use [PDF] in Stockholm.
At the same time, the researchers overlook more recent work: some showing the detrimental effect of fare increases on ridership (which could occur if subsidies are removed), and the positive effect of free passes on rider satisfaction (which could lead to increased ridership over the long run).
Despite the poor showing of fare subsidies, De Grange and colleagues don't mean to imply they should be eliminated. Rather, the numbers just suggest that subsidizing transit is the wrong policy to implement if a major city's main goal is increased transit ridership or decreased car use. In these cases, the money might be better spent funding a more reliable approach — like digging a rail extension so subway conductors can reach that new neighborhood after all.