The City of Boston this week is rolling out a new program that’s whimsically known as “Prescribe-a-Bike.” Part medicine, part welfare, the initiative allows doctors at Boston Medical Center to write “prescriptions” for low-income patients to get yearlong memberships to Hubway, the city’s bike-share system, for only $5.

These are not prescriptions in the legal sense. Rather, they are a kind of physician’s letter, says Alan Meyers, a pediatrician at Boston Medical Center. “A clinician working with a patient or family could generate this form and then a hospital parking office which is right on the campus could enroll the person in the program,” he explains. The hope is that signing low-income patients up for bike shares will help combat obesity, which disproportionately affects that community.

The $5 prescription rate Boston Medical Center is offering is significantly cheaper than Hubway’s $85 annual membership fee, and even beats the $6 24-hour-access pass often purchased by visitors. Boston has also waived credit qualifications for low-income patients, which have proved too much of a roadblock in the past, and is putting its own funds up to insure against potential losses or damages.

Perhaps the oddest thing about Prescribe-a-Bike is that it starts at the doctor’s office, yet its aims and functions are not strictly medical. Any low-income patient is eligible to receive a $5 membership from a physician, so long as the person doesn’t have a medical condition like a seizure disorder that could make biking dangerous. The program’s costs are being borne by the city, rather than any health insurance provider.

Meyers admits the setup is odd but says it’s not the first of its kind. Primary care providers at Boston Medical Center already write similar “prescriptions” that give low-income patients with nutritional needs access to the hospital’s own food pantry. The pantry itself is staffed by hospital personnel but funded by private charities.

The difference between the pantry and Prescribe-a-Bike, however, is that access to the first depends in part on medical need while the second is solely based on income. So why should a $5 membership require a doctor’s note?

The answer is probably that it shouldn’t. Meyers says the role of the physician goes as far as ensuring that the bike share is “safe” for the patient but ends there. It seems unnecessary to require doctors for that assessment – it’s not like every driver’s license needs to be approved by an M.D. Unless, of course, “prescribing” the memberships has less to do with medicine, and more to do with finding the right outreach point.

Consider the driver’s license once more. When you apply to get or renew a license in many states, the Department of Motor Vehicles attendant will ask you a question unrelated to your driving abilities – do you want to be an organ donor? Strictly speaking, there is no reason that organ donor sign-ups need to be conducted at the DMV. But the recruiting method turns out to be unparalleled in its effectiveness. NPR’s Planet Money did a great episode, “How to Bore Someone Into Donating an Organ,” explaining why this is in February. The basic idea is that the DMV acts as a point of contact – tons of people pass through the branches every day, and all they want is to get in and out. Plenty of them are happy to check an organ donor box as they go.

The doctor’s office is to Prescribe-a-Bike as the DMV is to organ donor sign-ups. Boston Medical Center is located in Boston’s South End, bordering on low-income neighborhoods like Roxbury and Dorchester. Hundreds of thousands of low-income adults and 25,000 low-income children funnel through the hospital’s facilities every year. Each of those people is a potential sign-up, especially if recommending the program to low-income patients becomes routine. “It’s really a point of convenience, and we hope that coming from a physician it may give people more of a stimulus to actually buy it,” Meyers says.

If you can bore people into donating an organ, maybe you can bore them into hopping on a bike, too.