Finance and Economics；Noise pollution: Shhh!

Why quiet carriages don't work, and how they might be made to

Quiet carriages on trains are a nice idea: travellers voluntarily switch phones to silent, turn stereos off and keep chatter to a minimum. In reality, there is usually at least one inane babbler to break the silence.

A couple of problems prevent peaceful trips. First, there is a sorting problem: some passengers end up in the quiet carriage by accident and are not aware of the rules. Second, there is a commitment problem: noise is sometimes made by travellers who choose the quiet carriage but find an important call hard to ignore.

The train operators are trying to find answers. Trains in Queensland, Australia, are having permanent signs added to show exactly what is expected; a British operator has invested in signal-jamming technology to prevent phone calls. Microeconomics suggests another approach: putting a price on noise.

Fining people for making a din would surely dissuade the polluter and is a neat solution in theory, but it requires costly monitoring and enforcement. Another tack would be to use prices to separate quiet and noisy passengers—in effect, creating a market for silence. A simple idea would be to sell access to the quiet carriage as an optional extra when the ticket is bought. Making the quiet coach both an active choice and a costly one would dissuade many of those who do not value a peaceful ride.

Charging may also solve the commitment problem. This is particularly tricky, as attitudes to noise can change during the journey. Some passengers would pay the quiet premium but still chatter away when some vital news arrives. Schemes that reward the silent—a ratings system among fellow passengers, for example—could help. The idea is that losing your hard-won reputation offsets the short-term gain from using the phone. But such a system also fails the simplicity test.

A 2010 book by George Akerlof and Rachel Kranton argues that “norms”—feelings about how everyone should behave—also play a role in decision-making. Charging a price, even if just a token amount, means the quiet carriage becomes a service that fellow passengers have bought, not just a preference they have expressed. Perhaps different norms would come into play, encouraging calm. If not, a personal bubble is always an option: noise-cancelling headphones start at around $50.