Why a Streetlight Is Hard to Sell One Person at a Time
A streetlight has two economic traits that make ordinary selling difficult. It is hard to exclude people from its benefit: once the lamp illuminates a sidewalk, a passerby can use that light whether or not they contributed. And it is largely nonrival: one person walking beneath it does not use up the light or leave less for someone else.
Those traits create a free-rider problem. If neighbors are asked to chip in, each may hope others will pay while they still enjoy the safer, brighter street. A private seller may struggle to collect enough voluntary payments to cover installation and upkeep, even when residents collectively value the service. The result can be too few lights, not because nobody wants them, but because willingness to pay is hard to turn into revenue.
Paying Collectively Changes the Incentive
A town can address the problem by funding streetlights through taxes or another shared contribution. Instead of trying to charge every person who walks past a lamp, it pools payments from the community and hires someone to provide the service. The payment is not tied to each resident’s individual use, which is precisely what makes broad provision possible.
This does not mean every service with shared benefits must be publicly run. Communities can also rely on voluntary groups, donations, or arrangements that make some users easier to charge. But when excluding nonpayers is difficult, those approaches may leave a service underfunded. The streetlight’s practical lesson is that who benefits and who can be billed are not always the same group—and that gap can determine whether a useful service gets built at all.
