Among the many casualties of the Great Recession are charitable groups. Last year, for example, donations dropped 11 percent, the largest drop in 20 years, according to the Chronicle of Philanthropy.

But as in other areas, this adversity presents an opportunity to create new, more innovative and better ways to encourage sustained giving to charitable causes. I propose a new idea that appears untested: "angel lanes."

The idea is simple: Commuters who ride the subway or travel along toll roads with electronic payment systems (like the East Coast EZ Pass) would be given the opportunity to have a donation to a designated charity automatically added to the commuting charge. Commuters passing through a subway terminal would be able to donate, say, 5 cents at the same time as they pay the normal fare. The subway authority would merely have to tally the number of swipes and adjust the total charge up by a nickel. Drivers could have a set amount added to their trip and donated to the American Red Cross, for instance, as they whiz through the toll booth.

This isn't an entirely new concept. For example, 16 cities across America have installed "parking meters" dedicated to charity collection next to real meters. Online, PayPal has instituted a virtual equivalent, so that with a click of the mouse customers can donate $1 to a designated charity, paid at the same time as the purchase.

But the "angel lanes" idea could have several advantages.

First, it would make charitable giving a public act. Other commuters would see your good deed. Such programs also would make donating an "owned" act, instead of a response to a solicitation. (How many of us don't give to panhandlers simply because the request, to put it bluntly, feels intrusive?) And finally, designated lanes or turnstiles could serve as important daily reminders of those in need.

But one of the biggest advantages of such a program is that it could help establish long-term habits of charitable giving. That's because commutes are ritually repetitive, performed almost automatically. By one estimate, 95 percent of human decisions are causally linked to automatic system processes, with only 5 percent caused by the reflective system. This striking division of labor reflects both how useful our "autopilots" are and how precious the capacity for reflective thought is. In fact, psychologists have described conscious self-control as a depletable resource.

Commuting is an automatic behavior for those who do it every day, so making "angel lane" donations would not only require almost zero cognitive effort, it could easily become habitual.

How much money could this kind of program potentially raise? In 2009, the Washington Metropolitan Area Transit Authority saw nearly 300 million Metrorail trips. If commuters in just 10 percent of those trips gave just a nickel, a local charity or city program could raise about $1.5 million a year. In New York, that same calculation would yield roughly $8 million a year.

Overcoming practical hurdles, like potential bottlenecks, would take time, as would determining the optimal amount of the donation. But tested and enacted carefully, they could establish valuable philanthropic habits and raise money for worthy causes like public schools. All without making you late for that 9 a.m. meeting.