Metro in Washington DC is considering fare surcharges for using the busiest downtown stations during the peak commute period. This is proposed as an alternative to a generalized 50-cent surcharge during the busiest part of the peak. The transit advocates at Greater Greater Washington are on board. The Transport Politic's Yonah Freemark objects:
But more fundamentally, one should ask whether it makes sense for a transit system to charge extra for exactly the service it is supposed to provide best: journeys to and from the downtown core at peak hours. Should the District of Columbia push for years to increase the number of office jobs downtown if it decides to reverse the game later on and disincentivize the use of the region’s primary transit service to get there? Why penalize the people who are using the system in exactly the way that the system was designed to work?
There's a pretty clear businessman's answer to that rhetorical question, but it's not something that most people want to hear: Transit ridership is determined by choices people make from among their available options. If transit is already much more attractive than the other available options (as is usually the case for commutes into a major CBD where motorists would face huge congestion and parking costs) the cruel facts of supply and demand argue that the fare for transit service in those situations can probably rise without much loss of ridership.
Of course, since we're talking about a government product, you won't win the argument using such cold calculus. Your argument has to be about fairness. Here, the case for peak surcharges is that they help people notice, and take account of, the very high cost of providing additional transit capacity during the peak period.
Service added to a network to handle peak-only overloading is very expensive service to operate. For example, drivers usually must be paid four-hour minimums for shifts that are actually as little as two hours, and the peak determines the number of vehicles that must be owned and maintained. Peak demand that flows in only one direction, as in the classic American single-centred city, also generates the huge inefficiency of moving all those vehicles, entirely or mostly empty, back in the reverse-peak direction. Sometimes, peak ridership is so much higher than midday that the fare revenue makes up for all these inefficiencies, but not often. In fact, my experience with American bus operators is that few of them have really counted the cost of their peak-only services.
To insist that peak service be priced equally to midday or weekend service is to argue that the riders of those off-peak services should subsidize the peak.
There's also an argument for peak surcharging that connects with urbanist goals for transit. People who have the option of travelling off-peak should be encouraged to do so, because off-peak capacity is usually abundant, while peak capacity is naturally scarce and costly for the transit agency. This strategy helps build off-peak patronage, which supports more all-day service, which leads directly to transit that is more relevant to the entire life of the city rather than just the commute. All-day frequent service is the only type of service that can support transit-oriented development and thus change the shape of the city in more sustainable ways. From an urbanist perspective, then, a gentle but persistent effort to shift demand away from the peak makes sense.
I have trouble even seeing a social justice argument against peak surcharges, as the average peak-period traveller usually has a higher income than an average midday traveller (because lower-paying jobs, mostly in service industries, are less likely to start and end on the usual peak). So insisting on flat fares all day could actually be seen as regressive.
In cases where (a) peak-only service adds hugely to system costs but (b) doesn't generate the farebox return to cover that impact, I can see only one credible reason not to surcharge the peak (or discount the midday, which is the same thing.) But it's a good reason: surcharges/discounts are an added layer of complexity in the fare system, and complexity in fares is a serious barrier to patronage, and especially to the informal, spontaneous use that lets people experience transit as essential community infrastructure. That’s the reason I usually use, but it only takes you so far in a network that’s groaning under peak pressure and desperately needs to encourage people to travel off-peak if they have the option.
My only comment about the specific Washington debate is that any surcharge should really be tied to the direction of demand where capacity is costly, namely into the city in the morning and out in the afternoon. A generalised surcharge on all peak travel will hit some people who make circumferential or reverse-peak trips where capacity is abundant and the incremental cost of peak service is zero. Thus, if the surcharge is tied to certain CBD stations, it should ideally apply only to station exits in the morning and entries in the afternoon. Again, though, the cost in system complexity -- "how long does it take to explain this?" -- has to be counted, and that often counts for quite a bit.
This posted is expanded from my comment on the Transport Politic post on this subject. See also the comment thread there.
UPDATE: In response to questions in the comments, let me clarify that I am talking only about situations -- likely to arise only in major cities -- where the differential cost of peak service is substantially higher than the differential in ridership, such that midday riders are effectively cross-subsidising peak riders. Any proposal for peak surcharges should rest on a thorough accounting of all the costs of peak-only service, including (a) minimum pay hours that exceed work hours, (b) deadhead time [time running empty to/from the garage or to return from a one-way peak run], and (c) all procurement, maintenance and storage costs for fleet used only during the peak.