Each time I walk to a Flexcar in my neighborhood, I pass scores of parked private cars. I sometimes fantasize about strolling up to one of them, swiping my Flexcard over the dash, and driving away. I'd be debited automatically; my neighbor would be credited, less a slice for Flexcar. And I'd have a vastly larger pool of vehicles at my disposal.

This fantasy is less fantastical than it may seem.

Advances in information technology and the growth of car-sharing could converge with trends such as high fuel prices, urban densification, and caps on carbon emissions to create a thriving market for private cars' idle hours—for people to pimp their rides.

The benefits for consumers and society would be colossal, and the obstacles to such a market emerging do not seem insurmountable. But I'm getting ahead of myself.

The starting point for this line of reasoning is the fact that cars and trucks are everywhere. From wherever you're sitting right now, I bet you can either see or hear at least one. The Pacific Northwest has substantially more motor vehicles than licensed drivers. There are enough cars around that everyone in the region could climb into a vehicle and no one would have to sit in the backseat. In fact, most of us would be alone.

What's more, most of the time—23 hours a day on average—our vehicles are parked.

The degrading effects of this massive vehicle population on our climate, our communities, and our health are gargantuan, but forget all that for the moment. Just think like an MBA.

"Rent Me"

More than 12 million motor vehicles, each of them idle 23 hours a day—that's a mind-boggling stock of underutilized capital, Aside from our homes, most of us Cascadians have more money tied up in our cars than in any other physical assets. And they’re just sitting there in the driveway depreciating, their resale value diminishing with every passing hour. (It’s true! Cars depreciate even when they aren’t being driven.)

Anytime there’s such over-capacity in the economy, there’s also a profit opportunity for whoever can figure out a way to put the over-supply to productive use. So how might northwesterners reap rewards for their unused cars? Well, they could rent them out. Imagine parking at the office, flipping the "rent me" button on your dash, and earning a few extra dollars an hour until quitting time. Imagine leaving town for a week and coming back to learn that your vehicle had earned you $300 on the rental market? On the flip side, imagine that your car-sharing membership card gave you access, on a moment’s notice, to tens of thousands of private cars and trucks sprinkled around your city. You might shed one or more of your household’s own vehicles if you knew there were a hundred at your disposal within a ten minute walk.

Driving Toward Scale

Why hasn’t such a market for vehicles’ off-duty hours already developed? What are the practical or legal obstacles?

The practical obstacles are what economists call transaction costs, most of them having to do with information. How can potential buyers and sellers find each other? How can they conveniently ensure payment? How can they tend to liability and insurance?

Car-sharing companies such as Flexcar and ZipCar are hard at work reducing these obstacles. They’ve developed elaborate and expensive transaction and marketing infrastructure—smart cards, onboard computers and GPS trackers, online reservation and billing systems, refueling and car washing systems, advertising and member recruitment. The business challenge for them is to get adequate scale. You need a huge number of billable trips to amortize all that transaction overhead. To add trips, you need more cars, which are very expensive. The idea of creating a market for off-duty vehicles is a natural extension of the car-sharing business model. It’s also an idea that both Flexcar and ZipCar have toyed with.

From a car-sharing business perspective, what could be better than to extend your transaction infrastructure across not only the fleets of vehicles you own but also to private vehicles that might be plugged into your system? Even getting one private vehicle in a thousand plugged in would represent several orders of magnitude of growth in the car-sharing fleet. That's vastly more billable trips but no additional capital locked up in buying your own vehicle fleet.