The speedy deliveries from Jeff Bezos’ online shopping giant come with a web of invisible social costs. You’re running a half-marathon in two months and need new sneakers, so you’re roaming the online frontier of the promised land, aka Amazon, and notice your favorite author’s latest book listed along the side during checkout. So you add that to your cart, cursing the data gods, and a satisfying click confirms your order will arrive in two days. But wait, you’ve been looking for a new lamp too, so now it’s time to start on order No. 2. Amazon Prime has saved many frantic consumers, delivering forgotten presents or last-minute Halloween costumes, and its convenience keeps expanding: Members can also get same-day and one-day delivery options. But touch-of-the-button convenience adds to traffic congestion, carbon emissions and car accidents — “social costs” that consumers and companies don’t directly pay for, according to Miguel Jaller, an assistant professor of engineering at the University of California, Davis, who specializes in freight and sustainable transportation. So, Mr. Bezos, I propose the following: Help save the planet by telling Prime customers that they’re allowed one order a month. | 