The businessman at the front of the early boarding line for your last cross-country flight may have gotten there without enduring 100,000 miles sardined into Row 34. Quite possibly, his privileged frequent-flier status was a credit card perk — or even bought outright.
Lately, that concept of putting a price on convenience has been adapted as a way to manage traffic congestion. Going beyond the existing model of rewarding commuters who fill the empty seats in their cars, these programs offer access to lanes once reserved for high-occupancy vehicles.
A version of this article appeared in print on February 26, 2012, on page AU1 of the New York edition with the headline: The Car Pool Lane Can Be Yours, for a Price.