Car heads down subway stairs

By Rob Beschizza at 8:04 am Tuesday, Apr 24 • Comments • Share

A driver tried to drive into the Chaussee d'Antin La Fayette Metro station in Paris on Tuesday, reportedly having mistaken it for a subterranean parking garage. The driver, who gave his name as Johan, told AFP: "There's a sign saying 'Haussmann Parking' right in front (of the Metro entrance), and ... I made a mistake."

Parisian drives car down Metro stairs [AFP. Photo: REUTERS/Jacky Naegelen]

Using math to get out of a traffic ticket

By Maggie Koerth-Baker at 2:05 pm Tuesday, Apr 17 • Comments • Share

We've talked about arXiv here before. It's a pre-print server for scientific papers in the fields of physics, mathematics, and computer sciences. Basically, what that means is that scientists can post papers to the site without first putting that research through the process of peer review. And that's not a bad thing. ArXiv is a great way for scientists and mathematicians to critique each other's work and do a little bit of vetting before submitting the paper to peer review. That's why the faster-than-light neutrino reports were published on arXiv—the results looked so crazy that the researchers wanted their colleagues to figure out what had gone wrong before a prestigious journal got involved. It's a way of collaborating.

The other nice thing about arXiv: It's a great home for interesting data that doesn't necessarily have a place in a formal, peer-reviewed journal.

Case in point: "The Proof of Innocence", a paper in which physicist Dmitri Krioukov uses math to explain why the cop who stopped him for running a stop sign was clearly seeing things. Physics Central summarizes the first step in this defense:

When Krioukov drove toward the stop sign the police officer was approximating Krioukov's angular velocity instead of his linear velocity. This happens when we try to estimate the speed of a passing object, and the effect is more pronounced for faster objects.

Trains, for instance, appear to be moving very slowly when they are far away, but they speed past when they finally reach us. Despite these two different observations at different distances, the train maintains a roughly constant velocity throughout its trip.

In Krioukov's case, the police cruiser was situated about 100 feet away from a perpendicular intersection with a stop sign. Consequently, a car approaching the intersection with constant linear velocity will rapidly increase in angular velocity from the police officer's perspective.

Krioukov's basic argument: The officer thought he saw Krioukov speed right through the sign. But he was wrong. Instead, Krioukov stopped at the sign, but stopped very quickly and sped up quickly, both of which happened out of the cop's direct line of sight.

It's worth noting that this argument was good enough to get Krioukov out of a $400 fine.

Read Krioukov's paper.

Read the summary on Physics Central.

Image: Stop, a Creative Commons Attribution (2.0) image from misteraitch's photostream

How traffic jams are born

By Maggie Koerth-Baker at 11:00 am Tuesday, Jan 17 • Comments • Share

A couple of years ago, Cory posted a really interesting story about the mathematics behind seemingly cause-less traffic jams. It's pretty interesting. Shorter version: The researchers think jams like this are caused by one person braking, and the response to that slow down moves through dense traffic in a way that is mathematically very similar to the shock wave from an explosion. Once you have enough density of cars on a road, jams are inevitable.

Cory's post included a simulation, showing what the mathematics might look like in the real world. Basically, a computer algorithm figured out how drivers would behave if the mathematical theory were correct and turned that behavior into a little cartoon of cars moving around a track.

But here's the really cool thing. This effect has actually been demonstrated in meatspace. Yesterday, a friend sent me a video from 2008, showing real life drivers behaving in almost the exact same way as the simulation video from Cory's post. That's what you see posted above. Now, these are not exactly real-world conditions. A flat circular track may, or may not, be a good representative for what happens on the highway—I, for one, would be interested in seeing how on/off ramps, hills, and curves change the patterns. Also, the drivers in this case were other students and faculty from the Nakanihon Automotive College, and the study doesn't say whether they knew why they were driving in circles. Again, these details could affect the outcome.

I've not been able to find any studies that test this mathematical model by documenting real-world traffic flows. But if you've got links, I'd love to see them! The idea behind this theory certainly makes sense and it would be interesting to know whether it matches up with the reality you and I experience.

Video Link

Thanks, Andrew Balfour!

DeLorean buffed to mirror-finish

By Rob Beschizza at 3:25 pm Thursday, Jan 5 • Comments • Share

On the Autopia forums, AkamaiDetailing recently unveiled his brushed-steel DeLorean, polished and buffed to a mirror finish: "This took an insane amount of time, but it was so worth it. Has anyone else done this before?" They have indeed.

Footage from test runs of Google driverless cars

By Maggie Koerth-Baker at 7:50 pm Wednesday, Oct 19 • Comments • Share

Google has been testing out its self-driving cars on real roads. This is still a long way from being available for you to purchase, but it's clear that it's working surprisingly well on a technological level.

You can watch some footage, recorded in the driverless cars during their test runs, in the video above. IEEE Spectrum's Erico Guizzo (who, incidentally, says he's a lot less skeptical of Google's goals after seeing this video) explains what makes the system work.

Two things seem particularly interesting about Google's approach. First, it relies on very detailed maps of the roads and terrain, something that Urmson said is essential to determine accurately where the car is. Using GPS-based techniques alone, he said, the location could be off by several meters.

The second thing is that, before sending the self-driving car on a road test, Google engineers drive along the route one or more times to gather data about the environment. When it's the autonomous vehicle's turn to drive itself, it compares the data it is acquiring to the previously recorded data, an approach that is useful to differentiate pedestrians from stationary objects like poles and mailboxes.

The video above shows the results. At one point you can see the car stopping at an intersection. After the light turns green, the car starts a left turn, but there are pedestrians crossing. No problem: It yields to the pedestrians, and even to a guy who decides to cross at the last minute.

Video Link

Via Bryan Walsh

Teen driving restrictions don't have as big an impact as expected

By Maggie Koerth-Baker at 7:39 am Thursday, Sep 15 • Comments • Share

My friend Jim captured this excellent moment in science reporting this morning. Thankfully, as I check Google News now, the headlines are drifting more towards the real story, which is fairly interesting. Turns out, deadly car accidents aren't so much a function of driver age as they are a function of driver experience.

Basically, over the past few decades, several states have placed stringent limits on teenage drivers—usually when they can drive, and who they can drive with. The idea was to separate first-time drivers from risky driving situations, and a lot of people assumed these measures were saving lives. Instead, we now know, the rules merely shifted when the deadly accidents happened. Some lives were saved. But, in general, the results were pretty much a wash.

The researchers found that states with the most restrictive graduated licensing programs — such as those that required supervised driving time as well as having night-driving restrictions and passenger limitations — saw a 26% reduction in the rate of fatal crashes involving 16-year-old drivers compared with states without any restrictions.

But the rate of fatal crashes among 18-year-old drivers in those states jumped 12% compared with the states without restrictions.

A similar trend was seen when comparing drivers in states with strong graduated licensing programs with those in states with weak programs: The rate of fatal crashes among 16-year-old drivers was 16% lower but was 10% higher among 18-year-old drivers.

Overall, since the first program was enacted in 1996, graduated programs were linked to 1,348 fewer fatal crashes involving 16-year-old drivers and 1,086 more fatal crashes involving 18-year-old drivers.

The speculative response: You can place restrictions on new drivers that limit their exposure to situations where mistakes are likely to happen. But, eventually, they'll have to navigate those situations on their own. And when they do, the mistakes creep back in. So maybe we need to look for a better way to mitigate the mistakes than simply instituting age-dependent restrictions. Personally, I wonder what the results would be if driving education included time to practice driving (either virtually or on a test course) with the distractions they're likely to encounter in real life. I know I learned how to drive and talk at the same time, and how to know when to shut everybody up, by experience. Maybe there's a way to do that in a safer environment.

Hitting 52.5 mpg won't require major tech advancement

By Maggie Koerth-Baker at 9:48 am Tuesday, Aug 23 • Comments • Share

By 2025, US automakers will have to have an average fleet fuel economy of 52.5 miles per gallon. That standard is 27.3 mpg today, so it sounds like a great, big, scary leap. But not really, say vehicle technology experts. In fact, there's enough room for improvement in things like auto-body design, that we can meet the new goal without needing any major technological breakthroughs.

3 things you need to know about biofuels

By Maggie Koerth-Baker at 8:30 am Friday, Aug 5 • Comments • Share

Why care about liquid fuel?

There’s a reason we use different forms of energy to do different jobs, and it’s not because we’re all just that fickle. Instead, we’ve made these decisions based on some combination of what has (historically, anyway) given us the best results, what is safest, what is most efficient, and what costs us the least money.

In a nutshell, that’s why liquid fuel is so valuable. So far, it’s the clear winner when we need energy for transportation—especially air transportation and heavy, long-distance shipping—because it allows you to stuff a lot of energy into relatively small amount of storage space, and easily refill on the go. There are other options, of course, like electricity. And that can work quite well, depending on what you’re trying to do. Eventually, we may find ourselves in a world where liquid fuel is no longer the best option. But we aren’t there yet. And for those forms of transport that take us into the air or move our belongings very long distances, we aren't likely to get there for a good long time.

That's why I care about liquid fuel, and why I'm interested in the future of biofuels. Yes, biofuels do have a future. But what that future will be depends on whether we can control for some very messy variables. Here, in three points, are the big things you need to know about biofuel.

1. Corn ethanol really is flawed. But maybe not as much as you think.

Biofuel is a nice, round word encompassing a lot of tricky, little, oddly shaped dots. You can make biofuel from lots of different things, in lots of different ways. Corn ethanol, cellulosic ethanol, bio-oil, bio-diesel, algae oil—they all have some benefits and some detriments, which means they all have some big backers and some big haters. Right now, any biofuel produced at a big, commercially useful scale is bound to be ethanol, and in the United Sates, that means corn ethanol. But, from what I see, the evidence favors using options that aren’t dependent on a dedicated corn crop. That’s not to say that corn ethanol is the devil—its bad reputation comes, at least in part, from backlash against some pretty heinous overselling—but it does have some big drawbacks and we might have an easier time making truly Green biofuels another way.

Read the rest

NASCAR prayer (video)

By Xeni Jardin at 10:43 am Monday, Jul 25 • Comments • Share

[Video Link] A pre-race prayer at the NASCAR Nationwide series race in Nashville Tennessee, on July 23, 2011. "We want to thank you, Lord, for these mighty machines.... Lord I want to thank you for my smokin' hot wife.... Boogity Boogity Boogity. Amen." (via Tabitha Hale on Google+)