Archive for April, 2009

At a number of schools in Los Angeles, parents are being press-ganged into serving as traffic safety officials to help protect kids from … other parents, driving kids to school.

From January to November 2008, there were 153 traffic-related injuries around schools, which Los Angeles public school officials said was much higher than five years ago, though they could not provide data for prior years…

…Increased traffic around schools has vexed other major cities, too. Nationwide, roughly 21 percent of morning traffic is generated by parents driving children to school, said Raquel Rivas, a spokeswoman for Safe Routes to School, a national organization formed to encourage walking and bicycling to school.

At the California Office of Traffic Safety Summit this afternoon in San Francisco, I was talking to AAA’s Steven Bloch about research the group did recently on compliance with California’s law requiring car drivers to use only hands-free devices while driving. He referred to an interesting finding, referenced in the link above, that came after sifting through the observational data: As might be expected, hand-held phone use while driving had declined, but hands-free use has actually declined as well since the law was passed (at least according to this survey).

No, correlation is not causation, but it’s intriguing nonetheless. Bloch theorizes (unscientifically, he stresses) one of two things is happening: One, the publicity about the law has raised awareness in general about the risks of talking on a phone — hand-held or not — while driving (and this trend shall pass); or two, that people have not fully understood the law, and may be confusing one form of phone with the other (I admit to sometimes taking a moment to comprehend what the ungainly term ‘hand-free phone’ actually signifies). A third possible idea is that people may somehow feel police will be looking more carefully at all drivers on a phone, regardless of whether it’s legal or not. Or perhaps there’s some other unknown factor at work. Or perhaps the sample size is simply not large enough; perhaps more people than ever are driving and talking.

Even so, the idea had me wondering about other cases where a law intended to curb one behavior had, unintentionally or not, also curbed an associated, though legal, behavior. Any thoughts?

My review of Daniel Sperling and Deborah Gordon’s Two Billion Cars is just out, in the new issue of The Wilson Quarterly.

Here’s a taste:

“Efficiency” is a soothing, lovely word that means little on its own: efficient as compared to what? Take the American car (please). As veteran transportation and energy specialists Daniel Sperling and Deborah Gordon write in Two Billion ­Cars—­their authoritatively prescriptive challenge to the “transportation monoculture” that plagues the United States and Europe and looms in China and India—automakers have been making their cars more fuel efficient on the order of two percent annually. And yet the actual “corporate average fuel economy” of cars has made less commendable gains: “The bottom line is that although technologically the modern U.S. car is more efficient than ever before, gaining more work from a gallon of gasoline, those efficiency gains don’t show up as fuel economy gains.”

What happened? All the efficiency gains were consumed, by size and horsepower (not to mention increased driving). In 1976, the Honda Accord, which captured the wallets, if not the hearts, of Americans reeling in the wake of high fuel prices, weighed 2,000 pounds and got a reported 46 miles per gallon in highway driving. “Ten million Accords later, the car had ballooned,” write Sperling and Gordon. “The 2008 model is 78 percent heavier, equipped with an engine nearly four times as powerful and loaded with power options.” It also gets 17 miles per gallon less on the highway than its predecessor. This example is not atypical: “Today’s granny car would have qualified as a performance car 25 years ago.”

The rubber hits the road, via Scotland.

In this Daily News story about a driver blowing a series of traffic lights before causing a fiery crash, I couldn’t help notice the banner for the “World’s First Automated Parking Facility,” from a company called Automotion, in the background of the singed Mercedes.

This was the first I had heard that my humble borough was to be home to such a remarkable contrivance. This bit of text seemed particularly ironic: “Working with a manufacturer that has over 90 automated parking projects worldwide, we have a proven system that delivers cars to their owners within 2 minutes…All without anyone touching the vehicle! No scratches, dings, or accusations of stolen personal items…Because no one ever touches the cars.”

Until they get out on the streets of Brooklyn, that is (and remember kids, it’s the traffic light cameras that we have worry about)…

A California woman who was texting while driving has been sentenced to six years for gross vehicular manslaughter. This is still a relatively evolving area of law so the sentence is noteworthy.

And despite heartfelt claims from Matis-Engle’s friends that she was a caring, loving and gentle person, Beatty said it was clear to her that the woman’s personality changed dramatically when behind the wheel of a vehicle.

She also said that Matis-Engle was well aware of the construction work on Highway 44 because she drove the roadway every day, but ignored eight highway construction warning signs and was concentrating on her cell phone - and not on her driving - when she slammed into Winn’s car near Dersch Road driving at least 66 mph.

These sentences convey an important truth; that most people involved in negligent driving of this sort aren’t “bad people” or homicidal maniacs, and to demonize them in that regard is counter-productive, as it may reinforce the notion among the rest of us that it’s the “other person” we all need to be concerned with, that our own driving is “above average,” etc. What does need to demonized, rather than blithely accepted and tacitly encouraged, is the culture of multi-tasking while driving. There is something else to note here. The incident happened on a road well familiar to the driver, but the circumstances had changed a bit, and the driver, while obviously thinking everything was under control, was actually under a severe attentional deficit — had there been a camera and eye-tracking software in the car we may have even seen the driver looking ahead (but “looking without seeing,” as it goes). A last point to make is that had the driver been intoxicated, the sentence would surely be higher still. As the science comes in on distracted driving, is the distinction between alcohol and texting going to hold?

(thanks Rich)

It’s long been known that SUVs are hardly the safest vehicles on the road, both for their occupants and the occupants of other cars (as well as pedestrians and cyclists).

A recent study published in Injury Prevention, “Non-fatal and fatal crash injury risk for children in minivans compared with children in sport utility vehicles” M.J. Kallan, K. B. Arbogast, M.R. Elliott, and D.R. Durbin, looks specifically at the safety of child occupants of those vehicles, and finds minivans come out on top.

In the New York Times “Wheels” blog, one of the study’s authors, Dennis Durbin, explains the findings:

When it came to crashes that caused injuries but not deaths, Dr. Dennis Durbin of the Center for Injury Research and Prevention said children in minivans were 35 percent less likely to be hurt than children in S.U.V.’s.

Looking at fatal crashes, there was a 24 percent greater chance of a child being killed in an S.U.V. than a minivan, the researchers found. Dr. Durbin said the reason for that was clear: S.U.V.’s had more rollover crashes. The study found that 66 percent of the S.U.V. fatalities involved a rollover, compared with 37 percent for minivans.

Rollovers, to be sure, account for a great deal of the difference. I might also argue that SUVs are driven differently due to the higher seat position of the driver (they feel as if they are moving more slowly than a driver in a lower vehicle).

But while the study wasn’t able look at driver behavior factors, this should not be overlooked. Different sorts of people are drawn to different vehicles, and they drive them differently. One of my favorite examples of this comes from Leonard Evans’ book Traffic Safety and the Driver. As the chart reproduced below shows (the car models are somewhat antiquated at this point), the crash involvement rate for vehicles was higher in the sedan version of the car than in the station wagon version, and it is generally higher in the two-door models than the four-door models. It is not, as Evans argues, that safety is a matter of simply adding a few more doors, or getting rid of the trunk. It is that “vehicle factors” sometimes matter less than human factors. Compounding the problem of course is that there has been a move away from minivans, never depicted as anything but safe and staid, into SUVs, whose marketing messages and vehicle characteristics are more often oriented toward aggressive driving (in fact there is anecdotal chatter about people moving into SUVs because they didn’t want to be branded with the “soccer mom” pejorative, as if SUVs themselves didn’t now have that legacy).

I’m still digesting all the information from a post over at Ian Walker’s blog concerning a reaction to his bicycle overtaking study, but I can’t shake from my mind the old Hank Kissinger saw, ‘academic disputes are so bitter because the stakes are so small.’

I would side with Ian Walker (who of course is featured in Traffic) in his assertion of cross-cultural differences. Nothing in the traffic world (fatalities, laws, norms, etc.) translates easily across borders — not even state borders. The U.K. driving population, the landscape, the safety rate, the regulations, etc., have little to do with U.S. traffic culture. And while I find the Gutierrez work interesting, I can’t also help thinking it comes shrouded in a militantly ‘vehicular cycling’ agenda — I really can’t imagine many civilians out there would even feel comfortable in the first instance riding on that road on which they’re riding (in L.A., where cyclist-car relations have been less than rosy), much less taking up big amounts of road space. Which points to a larger sort of question: Is this what we should be worried about to begin with? Is a cycling culture going to be built on a game of inches from cars overtaking at high speeds? I can’t imagine these are top-of-mind concerns in the Netherlands or Denmark (but I could be wrong).

But like I said, I’m still digesting, only wading into a very deep pool here (Google ‘vehicular cycling’) and primarily wanted to highlight the exchange.

I picked up the immensely pleasurable Schott’s Miscellany 2009 last night and was delighted to find a number of traffic-related nuggets.

A few:

Which state has the most drivers per 1000 pop.? Connecticut, with 800.

The fewest: New York, 577.

The state with the most miles of road is, not surprisingly, Texas; but I was surprised by the third entry: Kansas. Where does everyone go in Kansas?

I also learned that in 1996, 40.6% of 16 year-olds held a driver’s license; by 2006 that figure was 29.8% (not a bad thing, in my mind, as GDL is arguably the only teen driver intervention to show significant results; as someone recently joked to me at a traffic conference, ‘we should lower the drinking age to 16 and raise the driving age to 21′).

Then there’s an item from CNW Research about one’s car color and ‘how they felt about life.’ Weirdly, ’sunny yellow’ drivers were 3.7 below the average. But as Schott notes, “clearly, more robust measures of mental health exist.”

A funny bit in the New Scientist:

A SIGN on an overhead gantry on the M1 motorway near Leeds in the north of England reads “THINK DON’T PHONE”. Rowan Brown is willing to do his best to obey this exhortation to use telepathy, but he is concerned that the effort involved would be even more distracting to his driving than using his phone would. He wants to be sure that the transport authorities who erected the sign are sure that “driving while engaged in telepathy” is safe and not an offence.

By the way, if anyone has a photo of that I’d love to see…

Ted Dewan at euroGel 2006 from Gel Conference on Vimeo.

Great presentation (about 20 minutes) by Ted “Road Witch” Dewan, who we’ve mentioned before, from the 2006 GEL Conference but only recently posted.

Also check out the “Life Begins at 20″ campaign, which look to institute a 20 mph speed limit on the streets of Dewan’s hometown, Oxford (the one in England).

(Thanks Jerry)

A great anecdote from an article in Smithsonian (which quotes Traffic) on risk compensation:

Soon after the first gasoline-powered horseless carriages appeared on English roadways, the secretary of the national Motor Union of Great Britain and Ireland suggested that all those who owned property along the kingdom’s roadways trim their hedges to make it easier for drivers to see. In response, a retired army colonel named Willoughby Verner fired off a letter to the editor of the Times of London, which printed it on July 13, 1908.

“Before any of your readers may be induced to cut their hedges as suggested by the secretary of the Motor Union they may like to know my experience of having done so,” Verner wrote. “Four years ago I cut down the hedges and shrubs to a height of 4ft for 30 yards back from the dangerous crossing in this hamlet. The results were twofold: the following summer my garden was smothered with dust caused by fast-driven cars, and the average pace of the passing cars was considerably increased. This was bad enough, but when the culprits secured by the police pleaded that ‘it was perfectly safe to go fast’ because ‘they could see well at the corner,’ I realised that I had made a mistake.” He added that he had since let his hedges and shrubs grow back.

I couldn’t help also think of a story today about a woman killed by a reckless driver (police think he was racing, and manslaughter charges are a possibility) in San Diego.

“Route 67 between Poway Road and Ramona has been the scene of numerous fatal crashes over the years. Calls to widen the winding route have been made for some time, but transportation and highway patrol officials say the real problem isn’t with the road but with the way people drive on it… Speeding is responsible for most of the crashes, they say.”

It’s amazing how short-sighted (not seeing the forest for the, er, hedgerows) people can be in this respect; widening the road is absolutely the last thing that will reduce what seems to be a speed problem.

The long-elusive silver bullet of traffic safety, if you read this press release, has arrived in the form of the … iPhone!

From the same company that produces a “speed trap” detection application for the iPhone, thus decreasing the safety of the road both in terms of speed and distraction, comes this bold claim:

Njection.com (http://bit.ly/gJjNa) added another layer to their Speed Trap mapping system today by including traffic accidents and fatalities to enhance their data visualization system. This addition will allow drivers to see where accident black spots and problem areas are. An updated Njection Mobile iPhone application [iTunes] (http://bit.ly/4ZFmg) that allows drivers to be alerted to these high accident areas is awaiting approval from Apple.

[uh, quick interjection; a good deal of crash blackspots are at intersections, which are typically controlled by traffic lights, and sometimes, because people don't seem capable of obeying simple traffic signals, red light cameras, which your software will also sniff out — thus potentially increasing the very crash blackspot-ness! How wonderfully intregrated!]

Njection.com has acquired accident data from the National Highway Traffic Safety Administration (NHTSA - http://bit.ly/C5gpV) and global weather conditions from WeatherBug.com (http://bit.ly/uwmK2), and coupled this information with Microsoft Virtual Earth (http://maps.live.com) to produce a unique use of data visualization. This Virtual Earth mash-up not only allows users to view 5 years of accident data collected from the NHTSA based on local weather conditions but to see it in 4-hour blocks updated every hour from the current time. For example, if it is 12PM and a user selects the “4 hour history” radio button, they will be shown a history of accidents that have occurred between 11AM and 3PM based on the local weather conditions.

I realize this is a press release (regurgitated without comment by Fox Business), and not to mention this is still early days for the iPhone — every app is announced with breathtaking excitement, but most will be revealed as useless geegaws, to be marveled at over drinks for fifteen minutes with your friends and then cast into the silicon attic.

But apart from the incredible irony of this company suddenly being concerned with “safety” this is incredibly wrong-headed on several fronts. First, as any number of SatNav crashes have shown, taking drivers eyes and minds off the road, reducing their situational awareness, is not a good idea. Full stop. Rather than scanning some tiny screen to look for time-and-weather coded crash data, one should actually be looking at the actual conditions of the road one is on.

Then, there’s the problem of regression to the mean. A place may be an “accident black spot” for a time, then have no crashes for the next number of years. What are we to do with that information? And, given that the vast majority crashes have driver behavior at their root, not slippery bridge surfaces and the like, presenting crash data as somehow a function of road conditions is disingenuous. And, as always, does highlighting places of greater crash frequency leave one less vigilant at other locations?

The best way the iPhone could contribute to traffic safety in the car — apart from the long-awaited breathalyzer app — is it for it to be turned off.

Faithful readers of Traffic will know of my fascination with the traffic organization of ant colonies. I’ve just been reading a new paper, “Priority rules govern the organization of traffic on foraging trails under crowding conditions in the leaf-cutting ant Atta colombica,” published in a recent issue of The Journal of Experimental Biology, by Audrey Dussutour and colleagues from France’s Université Paul Sabatier.

Dussutour, working with a colony at the University of Illinois, manipulated a bridge on an ant trail so that it was too narrow for two opposing streams of ants to pass abreast. A clear pattern emerged: Ants heading out to the food source always gave way to returning ants that were laden with food (some of which were followed by ants without food). A set of “clusters” emerged, which had its own interesting pattern in same-direction traffic: Even though the ants returning without food were in theory held up by the slower, leaf-carrying ants, those ants still refused to “jostle” past. The results of this strategy were worth noting:

As unladen ants move on average faster than laden ants, these ants were thus forced to decrease their speed. By contrast, this decrease was counterbalanced by the fact that, by staying in a cluster instead of moving in isolation, inbound unladen ants limit the number of head-on encounters with outbound ants. Our analysis shows that the delay induced by these head-on encounters would actually be twice as high as the delay induced by the forced decrease in speed incurred by ants staying in a cluster.

A strategy that appeared to be slower for some individual ants actually benefited the colony as a whole; this is a pattern that often does not hold in human traffic — when, for example, individuals change lanes in unstable traffic, perhaps temporarily improving their own position but having what Benjamin Coifman terms a “butterfly effect” on the lane they have moved into, as well as the one they left.

The French team’s experiment reminded me of a passage from Robert Frank’s book The Economic Naturalist. Frank, based at Cornell, writes about the quaint old one-lane bridges around Ithaca, New York. He notes that a “first come, first served” social norm has emerged at the bridges, so that a stream of steady traffic from one direction wouldn’t hold up cars from the other direction for an undue amount of time. Typically, self-restraint, as in the case of the ants, can help improve overall efficiency.

But when traffic is heavy from both directions, he notes, this norm actually penalizes drivers. As he writes:

“Suppose a ten-car caravan arrived from each direction, with ten seconds separating the cars in each caravan, and with the first driver in the northbound caravan reaching the bridge a split second before his counterpart in the southbound caravan. If no one followed the first-come, first-served norm, all northbound cars would cross the bridge, after which the ten southbound cars would cross. Northbound cars would experience no wait at all, and as readers with a pencil, paper, and a little patience can easily verify, the southbound drivers would experience total combined waiting time of twelve minutes and thirty seconds… In contrast, if all followed the first-come, first-served norm, the first northbound car would cross, followed by the first southbound car, then the second northbound car, followed by the second southbound car, and so on. If you are patient enough to add up the relevant waiting times, you will see the total waiting time would be 80 minutes—37.5 minutes for northbound cars and 42.5 minutes for southbound cars—more than six times as long as when there was no norm.”

Of course, at construction sites and the like, where a flagman is present to wave clusters of vehicles through, this problem does not exist or is mitigated.

I am not sure what the implication of this is. Perhaps we humans simply prize courtesy over rote efficiency (though overall the logic of traffic seems to be that everyone pursues his or her individual efficiency, beyond any impulse towards altruistic politeness). Perhaps it is because we have not evolved to act in concert, as ant colonies have (as Dussutour, et al. note, “ants from the same colony presumably act with a unity of purpose very different to the multiplicity of individual interests pursued by pedestrians or drivers moving in a traffic stream”). Perhaps the Ithaca bridges are simply outmoded in an era of heavy traffic. And on those Ithaca bridges there’s no clear hierarchy of commuters, as in the ant example. But it’s not a stretch to say that a bridge metering system, perhaps inspired by some ant-traffic-derived algorithm, would get people home faster than the traditional way of doing things.