Archive for June, 2009

Via Jalopnik.

On heels of some recent findings in NYC that the cycle fatality rate has declined, I came across this report from CTC with a few other interesting stats:

1. London has seen a 91% increase in cycling since 2000 and a 33% fall in cycle casualties since 1994-98. This means that cycling in the city is 2.9 times safer than it was previously.

2. The Netherlands has witnessed a 45% increase in cycling from 1980-2005 and a 58% decrease in cyclist fatalities.

3. Copenhagen, 1995-2006: 44% increase in cycling, 60% decrease in KSIs, with cycle to work modal share rising from 31% to 36%.5.

An empty truck takes twice as long to stop as a full one. From 55 mph, a cargo-laden, 80,000-pound truck requires more than the length of a football field to stop on dry pavement. But the stopping distance doubles for an empty truck under the same conditions. “The braking systems on big rigs require both friction and traction,” explains Durant. “With an empty trailer, the braking capacity diminishes, and you lose traction. The rig could begin to bounce, or it might jackknife.

The whole piece, which contains a few other survival tips for driving among big rigs, is here.

There has been much written about the recent drops in traffic fatalities being a result of the bad economy, or the efforts of traffic safety campaigns (which, however laudatory, sometimes doesn’t explain the full picture; Massachusetts has the lowest seat-belt-wearing rate in the country and also, paradoxically, has the nation’s lowest per-mile fatality rate).

A new brief paper by Michael Sivak, “Mechanisms involved in the recent large reductions in US road fatalities,” published in the latest issue of Injury Prevention, makes the case, as shown in the above graph, that road fatalities have dropped more than miles driven, suggesting it’s more than a mere “exposure” issue. “The reduction in road fatalities,” he argues, “is the result of a change not only in the amount of driving, but also in the type of driving.”

What’s changed? While miles traveled have dropped across the board, rural miles driven — which are more dangerous than urban miles driven — have had a particularly steep drop (probably because rural incomes are lower and thus more affected by the economy/higher fuel prices). Sivak also suggests, though this is more logical supposition than empirical fact, that discretionary driving (e.g., the trips we don’t have to make) has been the first to go in the national mileage profile. Discretionary driving is riskier than things like commuting to work, Sivak notes, as it tends to be marked by “higher speeds, greater involvement of alcohol, and more night-time driving.”

In other words, while the recent drops in fatalities are to be welcomed, it does not necessarily follow that they would hold once the money (and fuel) started flowing again.

Some random things on a too-busy Monday morning:

I’m briefly quoted in this piece about the ins-and-outs of parallel parking.

I also show up briefly and (seemingly) unidentified in this Good Morning America piece about Iain Couzin and ant traffic.

More on the theoretical physics of traffic. “A traffic jam starts with two vehicles and keeps on growing,” says Morris Flynn of the University of Alberta.

Why you shouldn’t help direct traffic at a crash site or similar situation.

New Mexico five-year-old sentenced for not wearing seat belt.

Roadguy ponders: Are shopping-mall stop signs optional?

Black-market parking: “Rogue valets” exposed in Los Angeles

As this blog has noted before, the news media seems to go out of its way to avoid ascribing personal responsibility in any sort of traffic crash (I am now calling this segment ‘The Accidental Journalist’). I just came across this weird doozy of a sentence in this article, about a “problem” intersection in Georgia:

On Deans Bridge Road at Gordon Highway, rear-end accidents are occurring in the right-turn lanes.

Drivers are stopping at the yield sign and causing accidents for those not paying attention behind them. Mr. Cassell said officials are looking at correcting the problem with new lane striping.

Let me get this straight. Drivers are stopping at the yield sign, which they are required to do when there is approaching traffic, and thus “causing accidents” to the poor sods (or “causing accidents for,” in this article’s odd wording) behind them who are not, uh, paying attention. I propose this wording: Inattentive drivers are crashing into the unsuspecting behinds of law-abiding folk.

I’m also not sure how you fix rear-end crashes with lane striping, FWIW.

Sign nuts: Don’t miss Daniel Pink’s pecha-kuchka presentation on “emotionally intelligent” signage, as referenced in the previous post.

Reader Shasha sends in this great example of merging property rights with some home-made driver beahvior modification. Considered it entered in the new MUTCD — the Manual of Unofficial Traffic Calming Devices.

Shasha’s rationale was as follows:

We live on a small and relatively quiet road. The speed limit on our road should be 40 (curves, narrow, and hills). However, like all county roads in our county, the speed limit is 55. This means that people actually attempt to go 55 or faster.

So, I decided to put up signs on my own land. I figure if they are funny and memorable, people may think and slow down. Or, if nothing else, they will slow down simply to see the signs. This sign (Watch for Flying Monkeys) comes from a picture I took of SuperS who was swinging from a rope in the front of our house. Yes, he appeared like a monkey. I thought it would be perfect. With a little design magic, I created a sign and posted one on each side of the road — as people approach our house / driveway.

I’m not sure it’s emotionally intelligent signage however, as it asks us to have empathy for flying monkeys, a creature few of us have seen.

I’ve often thought it interesting that congestion charging tends to appeal to aspects of both the right (e.g., free-market economists) and the left (e.g., public transportation advocates). You might say that the economists want better roads and less trafic, while the public transport people want more government directed toward their favored mode (and away heavily subsidized roads).

In any case, this left-right alliance was made strikingly clear in the recent response to U.K. transport secretary Geoff Hoon’s recent gloomy comments on the prospect of nation-wide road-user pricing, as the FT notes here.

Stephen Glaister, director of the pro-motoring RAC Foundation, said a system of direct charging for road use was vital to providing the revenue for expanding the road network.

Stephen Joseph, executive director of the pro-public transport Campaign for Better Transport, said a road-pricing system was inevitable if growing congestion on Britain’s roads was to be tackled and demand managed.

It’s hard to immediately think of another issue which unites these disparate groups, if for different end results.

That’s what I’m taking away from this WSJ piece.

I was intrigued by these remarks from Peter Gordon:

I have just finished reading The Horse in the City (by Clay McShane and Joel Tarr), which does a fine job documenting what went on (in American cities) between the years of the “pedestrian city” and the “automotive city”. The book is a fascinating bit of research on modern urban history.

But GM sold just over 2-million vehicles in 2005. The Detroit Big-3 sold 5.33 million. The U.S. population in 2005 was about 4.7 times that in 1890. The ratio of vehicles then and now is 1:5.33. So we are in the ballpark. But McShane and Tarr make no mention of demands for bail-outs or nationalization because the industry of its day was “too big to fail.”

Any old hansom cab builders out there care to comment?

David Levinson ruminates on the origins of the word “commute.” Like the word “traffic,” it seems to have had a strictly commercial orientation (to commute money at a currency exchange) originally, but then expanded to include the flow of people, not just goods.

I hadn’t seen this bit of E.B. White verse:

One who spends his life

And then rides back to shave again.

Traffic, Moscow-style. Keep an eye out for the intrepid pedestrian.

George Carlin is a serious rival, and Jerry Seinfeld has his moments — and any other suggestions are welcomed — but I submit to you the following road-related quips from the Brillo-headed surrealist:

My house is on the median strip of a highway. You don’t really notice, except I have to leave the driveway doing 60 MPH.

The other night I came home late, and tried to unlock my house with my car keys. I started the house up. So, I drove it around for a while. I was speeding, and a cop pulled me over. He asked where I lived. I said, “right here, officer”. Later, I parked it on the freeway, got out, and yelled at all the cars, “Get out of my driveway!”

Philip Greenspun raises an interesting idea based on some recent (crowded) drives in California: Why should a state with a $25 billion budget deficit give away one of its most valuable assets — highways — for free?

(Horn honk to Devorah)

If time permits I’ll be attending this entry at this year’s New York Science Festival (I’ve interviewed all three of the participants).

From Insects to Interstates

Anna Nagurney is the John F. Smith Memorial Professor in the Department of Finance and Operations Management at the University of Massachusetts, Amherst. Her research focuses on congested transportation networks and their relationship within different systems ranging from the Internet to global supply chains to electric power generation and distribution networks.

Photo by Simiant/Flickr.

“While in 1983 a pothole would need to be over 3 inches in depth and over 30 inches in
length to pose a rim damage threat to even a mini-compact vehicle, in 2006 holes as shallow as
1½ inches no more than 16 inches long could, in theory, cause rim damage.”

That’s from Influence of Road Surface Discontinuities on Safety: State of the Art Report, a new TRB circular.

The reason is “plus-size tire rims,” a form of road social signaling that basically says, “I’ve got money to spare on rims” that will soon need to be replaced.

“The principal disadvantages [of plus-size rims] are many and include cost, weight, fuel economy, ride quality and wet grip/snow traction, as well as indicate hydroplaning resistance. Perhaps more serious downsides include reduced load-carrying capacity at extremely low aspect ratio, a shift in the handling balance toward oversteer and a slight increase in rollover propensity. A further disadvantage is that the increased vertical stiffness of low aspect ratio tires means they act as shock transmitters rather than shock absorbers. Safety implications arise when a motorist will agree to replace a bent wheel that is no longer able to hold air, but will continue to use an injured tire since the damage is internal and not visible to the naked eye.” (Walter, J. Style Over Substance. Tire Technology International, March 2006.)

The authors also conclude, by the way, that potholes have little negative effect on road safety.

And one last thing: The vehicle brand above is now the property of an obscure Chinese company. Will they still be adorned with all those ultra-patriotic bumper stickers?

Reading this article about “intelligent speed adaptation” — or devices that limit speeds according to the posted speed of the road (imagine that!) — in Australia (where most of the ISA research is being conducted), I was curious about this phrase:

In cases of emergency there is an override system whereby the driver can either flick a switch or floor the accelerator to disable the safety device and put the car back in manual control.

The immediate question that springs to mind is how long can the device be disabled for? Would drivers not simply disable it for their entire trip? Is ISA meant to be a merely advisory technology, a bit of feedback to discourage speeding, or an actual enforcement mechanism? I tend to think the whole issue of hypothetical speeding for some emergency is a bit overblown (when compared to the potential safety benefits of ISA) — for something like crash avoidance, braking is typically just as valid a response. On the other hand, there are moments on Australian roads, as in the photo above, where a bit of speed might be desirable.