In theory, Sidecar is about sharing. Here’s how it’s supposed to work: You're headed downtown in your car, but before you leave you check your Sidecar app. A user a few blocks down is looking for a ride in the same direction. You swing by, pick her up, and drop her off. Everyone wins by sharing -- she gets to her destination, and you get to feel good that the gas you just burned went towards transporting more than one human being. (Plus, Sidecar suggests that she “donate” a little cash to you for your trouble.)

In practice, Sidecar seems to work something like a taxi. There's no meter, and in beta trials, the suggested donation for longer trips beat actual car services -- but it's not clear that the people giving rides are just average Joes who happen to be going someplace. Instead, this might be their side business. Sidecar screens all the drivers, and the one example of a driver that Wired offers is a laid-off bank employee who uses the service to supplement his income.

If you lived at the Watergate, this is how long your commute would be around the city by car. Good news is that should you be heading to, say, the White House, you can get there in about 10 minutes. (Probably faster under cover of darkness.)

Should you choose instead to travel by public transit, the trip takes slightly longer, but it's easier to blend in with crowds.

These images were generated by Trulia's awkwardly named "Visual analysis of local data" tool, henceforth known as the Commute-o-matic.™ It's less complicated than it seems. The tool looks at known public transit routes (bus stops, train stations) and the travel times between them. What makes it look magical is the speed with which it makes the calculations.

In most cities, you can almost always get more places in less time by car. That revelation won't shock you, though the extent of the problem might. Compare San Jose with San Francisco. Huge difference in what public transit allows.

Taizhou lies 190 miles south of Shanghai and has 6 million people, putting its size at “somewhere in between Los Angeles and New York City” on a U.S. scale and “just some town” on a Chinese one. One day recently, though, the streets were filled not with cars, scooters, or pedestrians, but with ducks. Thousands upon thousands of ducks:

Photo by Trevor Stoddart.

Obviously, everyone loves a nice strip mall. The parking lot, the low-slung, cheap-looking buildings, the pedestrian walkways that no drivers pay attention to.

And big-box stores! The lots! The long walks down busy parking lanes! The Brutalism-meets-Brady-Bunch aesthetic! What's not to like?

So it pains me, truly,  to be the bearer of this bad news. There's a slight (actually, not-so-slight) correlation between strip malls and big-box stores and increased deaths among the elderly.

A recently released report [PDF] from the Texas Transportation Institute at Texas A&M is the bearer of this bad news. Anticipating that some 10 percent of the population would be 75 or older by 2050, they set out to study how the design of traffic flow within a community related to accidents involving pedestrians and drivers at that advanced age.

Photo by twicepix on Flickr.

In a report released yesterday, the World Health Organization (WHO) declared exhaust from diesel engines to be a carcinogen [PDF] -- the same status as secondhand smoke. In 1989, the fumes were deemed a "probable carcinogen." The suspected culprit? Particulate matter expelled during diesel fuel combustion. Gasoline exhaust, with a different chemical makeup, remains a possible carcinogen.

As reported by CBS News, the WHO study looked at a population of 12,000 miners over the course of the past 60 years. Those regularly exposed to diesel exhaust had three times the rate of lung cancer deaths as their peers.

Nature abhors a vacuum, but transit nerds and people eager to see a science fiction future LOVE IT. That's because a vacuum is the secret ingredient for this (theoretical, but plausible) superfast train, which could speed under the ocean to get you from New York to London in one hour, or New York to Beijing in two.

Image by Zoli Erdos.

Okay, everyone. Take a deep breath. The new Apple operating system didn't kill walking and public transit directions, as some have feared.

Feeling better? Good. Here are the details.

I happen to be a registered Apple developer. I'd like to pretend that it's because I'm constantly creating new, lucrative iPhone apps, but it's actually because I accidentally screwed up my phone last year and had to register as a developer in order to unbreak it. The plus side: I get to download beta versions of the Apple iPhone software, iOS. In order to test the validity of claims that Apple was planning to ship without walking or public transit directions, I downloaded iOS 6.

Here's what I found.

This is Nummy. From "Life With Roozle."

Casey Carey-Brown, a Boston woman who blogs about her daughter "Roozle," has chronicled a harrowing story about childhood trauma narrowly averted by big-hearted transit workers. It concerns Roozle's toy bunny Nummy, pictured above. (Roozle is the human child, Nummy is the bunny. I just don't want you getting confused and thinking this was almost way worse than it almost was.)

Here's the setup:

Today, Nummy had a great day at school and just before the train arrived to pick us up at Stony Brook, Roozle told us that Nummy was a little scared of the train and she needed to tell her it was okay, trains aren’t scary.

We got off the train at the very next stop, at Green Street. Just as we were getting off the train, somehow Nummy jumped out of Roozle’s stroller and out of her grasp and fell between the platform and the train, right onto the tracks. The entire train gasped. Nummy was gone. Roozle immediately started screaming, “My friend! Nummy! She fell on the tracks and now a train is going to run her over! She will be squished by the train! On the tracks! I NEED MY FRIEND!!!”

A version of this story first appeared on The Dirt.

Photo by Matt Johnson.

It doesn’t matter whether you have a Prius or a Hummer, you have the same environmental impact. So argues MIT landscape architecture and planning professor Eran Ben-Joseph in his fascinating new book, ReThinking a Lot: The Design and Culture of Parking.

Whatever could he mean? Cars, on average, are immobile 95 percent of the time, taking up the same 9-by-18-foot paved rectangle. All of those paved spaces increase runoff into streams and wetlands, create heat islands, increase glare and light pollution, and shape the character of our cities.

To grasp the magnitude of the problem, consider that there are 500 million surface parking lots in the U.S. alone. In some cities, parking lots take up one-third of all land area, “becoming the single most salient landscape feature of our built environment,” Ben-Joseph writes.

But to this day, he says, “parking lots are considered a necessary evil; unsightly, but essential to the market success of most developments.” So the time is definitely ripe to redesign the lot.

Photo by dok1.

Bill Griffin manages a call center in Pittsburgh. He'd planned on expanding his business, adding 150 jobs. He didn't.

The Port Authority of Allegheny County plans to cut 46 of its 102 bus lines in September, while raising fares by about 10% to 15%, to help close a $64 million budget gap. The fare increase and historic service cuts have drawn fire not only from angry commuters but also from business groups, which want the state to help out. Republican Gov. Tom Corbett says the transit agency needs to put its fiscal house in order first.

More than half of DialAmerica's 300 Pittsburgh employees travel to work on a bus line slated for elimination, said Mr. Griffin, a vice president. "When we moved into this complex, the No. 1 consideration was to be near a public-transportation line," he said.

Public transport plays a central role in local economies, but tight budgets and hefty pension obligations are pressuring transit systems, just as the economic recession and sluggish recovery have depressed the state sales-tax receipts that fund many transit systems around the country.

Without bus lines, even existing employees couldn't get to work. Expansion, then, was out of the question.