Roundabouts

 A straight line isn't always the safest path between two points.

The Washington Post has the story:

Roundabouts are (slowly!) eating the suburbs by Andrew Van Dam

"Compared with the hundreds of thousands of normal intersections peppering the American landscape, ruled by stop signs and traffic lights, roundabouts are rare beasts. But unlike the drivers they frequently confuse and bedevil, roundabouts are coming on fast.

...

"The modern roundabout relies on a geometric design that forces traffic to slow, plus a simple innovation born in 1960s Britain: the rule that people already in the circle get the right of way. In traditional rotaries and traffic circles, which still lurk in many East Coast cities, traffic moves faster and vehicles already in the circle often must yield to newcomers.

...

"Why add a roundabout, you might ask. Because roundabouts offer impressive safety gains. In general, a roundabout will drive down fatal crashes by 90 percent and cut all car-crash injuries by at least 75 percent, even while accommodating a higher volume of cars.

"At a rural two-way stop, the gains can be even more dramatic. A roundabout can slash all traffic injuries, both fatal and nonfatal, by almost 90 percent. After all, it’s almost impossible to blow through a roundabout at 60 miles an hour and T-bone a minivan — an all-too-common occurrence in typical rural intersections.

“That’s the beauty of the roundabout,” Rodegerdts told us. “It’s the geometry. It’s the curves that are doing the work. And not relying on a traffic-control device as the sole thing keeping you from colliding at high speed.”

***********

Nevertheless...here's a related NYT story:

The Exceptionally American Problem of Rising Roadway Deaths

Why other rich nations have surpassed the U.S. in protecting pedestrians, cyclists and motorists. By Emily Badger and Alicia Parlapiano

"In 2021, nearly 43,000 people died on American roads, the government estimates. And the recent rise in fatalities has been particularly pronounced among those the government classifies as most vulnerable — cyclists, motorcyclists, pedestrians.

...

"In the 1990s, per capita roadway fatalities across developed countries were significantly higher than today. And they were higher in South Korea, New Zealand and Belgium than in the U.S. Then a revolution in car safety brought more seatbelt usage, standard-issue airbags and safer car frames, said Yonah Freemark, a researcher at the Urban Institute.

"Fatalities fell as a result, in the U.S. and internationally. But as cars grew safer for the people inside them, the U.S. didn’t progress as other countries did to prioritizing the safety of people outside them.

“Other countries started to take seriously pedestrian and cyclist injuries in the 2000s — and started making that a priority in both vehicle design and street design — in a way that has never been committed to in the United States,” Mr. Freemark said.

"Other developed countries lowered speed limits and built more protected bike lanes. They moved faster in making standard in-vehicle technology like automatic braking systems that detect pedestrians, and vehicle hoods that are less deadly to them. They designed roundabouts that reduce the danger at intersections, where fatalities disproportionately occur.

"In the U.S. in the past two decades, by contrast, vehicles have grown significantly bigger and thus deadlier to the people they hit. Many states curb the ability of local governments to set lower speed limits. The five-star federal safety rating that consumers can look for when buying a car today doesn’t take into consideration what that car might do to pedestrians."

Motorcycles as donorcycles

 Here's an article from JAMA Internal Medicine, noting that motorcycle rallies produce an increase in organ transplants.

Organ Donation and Transplants During Major US Motorcycle Rallies  by David C. Cron, MD, MS; Christopher M. Worsham, MD; Joel T. Adler, MD, MPH; Charles F. Bray, BS; Anupam B. Jena, MD, PhD,  JAMA Intern Med. Published online November 28, 2022. doi:10.1001/jamainternmed.2022.5431

"Key Points

Question  Is the incidence of organ donation and transplants higher during major US motorcycle rallies?

Findings  In this cross-sectional study of 10 798 organ donors and 35 329 recipients of these organs from a national transplant registry from 2005 to 2021, there were 21% more organ donors and 26% more transplant recipients per day during motorcycle rallies in regions near those rallies compared with the 4 weeks before and after the rallies.

Meaning  While safety measures to minimize morbidity and mortality during motorcycle rallies should be prioritized, this study showed the downstream association of these events with organ donation and transplants."

***********

Helmet laws by State (only the States in orange require all motorcycle riders to wear a helmet):

I wonder what would happen if some State passed a helmet law saying that adults are free to ride without a helmet, but doing so automatically registers the rider as a willing deceased donor. (Such a law might decrease deceased donation by convincing more riders to wear helmets.)

HT: Alex Chan

Take a break: avoiding congestion in ant colonies and elsewhere

A recent paper in Science is introduced by the NY Times under this headline:

The Secret to Ant Efficiency Is Idleness

Here's the paper:
Collective clog control: Optimizing traffic flow in confined biological and robophysical excavation
J. Aguilar, D. Monaenkova, V. Linevich, W. Savoie, B. Dutta, H.-S. Kuan,  M. D. Betterton, M. A. D. Goodisman, D. I. Goldman

Here's the abstract of the paper (preceded by another description, perhaps written by a writer for Science(?) meant to be more intelligible...

When fewer workers are more efficient:
"A narrow passageway can easily become clogged or jammed if too much traffic tries to enter at once or there is competition between the flow of traffic in each direction. Aguilar et al. studied the collective excavation observed when ants build their nests. Because of the unequal workload distribution, the optimal excavation rate is achieved when a part of the ant collective is inactive. Numerical simulations and the behavior of robotic ants mimic the behavior of the colony."

Abstract: Groups of interacting active particles, insects, or humans can form clusters that hinder the goals of the collective; therefore, development of robust strategies for control of such clogs is essential, particularly in confined environments. Our biological and robophysical excavation experiments, supported by computational and theoretical models, reveal that digging performance can be robustly optimized within the constraints of narrow tunnels by individual idleness and retreating. Tools from the study of dense particulate ensembles elucidate how idleness reduces the frequency of flow-stopping clogs and how selective retreating reduces cluster dissolution time for the rare clusters that still occur. Our results point to strategies by which dense active matter and swarms can become task capable without sophisticated sensing, planning, and global control of the collective.

Modern congestion pricing, by Cramton, Geddes and Ockenfels

Here's a short paper in the July 31 Nature:
Set road charges in real time to ease traffic
Track vehicles to link tolls with demand and cut congestion, urge Peter Cramton, R. Richard Geddes and Axel Ockenfels

And here's the longer working paper:
Markets for Road Use: Eliminating Congestion through Scheduling, Routing, and Real-Time Road Pricing
Peter Cramton, R. Richard Geddes, and Axel Ockenfels

Their vision:

"Efficient pricing of network capacity is not new. Indeed, wholesale electricity markets have been dynamically priced for over a decade. Communications markets are adopting dynamic pricing today. Efficient pricing of road use, however, has only recently become feasible. Advances in mobile communications make it possible to identify and communicate the location of a vehicle to within one cubic meter—allowing precise measurement of road use. User preferences can be communicated both in advance to determine scheduled transport and in real time to optimize routes based on the latest information. Computer advances also facilitate efficient scheduling and pricing of road use. Consumer apps help road users translate detailed price information into preferred transport plans. Computers also allow an independent system operator to better model demand and adjust prices to eliminate congestion and maximize the total value of road infrastructure. An independent market monitor, distinct from the
operator, observes the market, identifies problems, and suggests solutions. A board governs the market subject to regulatory oversight."

Too many traffic jams: an interview with Stanford's Mike Ostrovsky (and a paper by Ostrovsky and Schwarz)

Mike Ostrovsky at Stanford GSB is interviewed on technology and traffic:
An End to Traffic Jams? It Might Not Be a Dream

And here's the paper on which the interview is based:

Carpooling and the Economics of Self-Driving Cars
Michael Ostrovsky and Michael Schwarz
February 12, 2018

Abstract: We study the interplay between autonomous transportation, carpooling, and road pricing.We discuss how improvements in these technologies, and interactions among them, will affect transportation markets. Our main results show how to achieve socially efficient outcomes in such markets, taking into account the costs of driving, road capacity, and commuter preferences.  An important  component  of  the  efficient  outcome  is  the  socially  optimal  matching  of  carpooling riders.  Our approach shows how to set road prices and how to share the costs of driving and tolls among carpooling riders in a way that implements the efficient outcome

London crossing signs and diversity in marriages

Walking from HM Treasury to LSE, a quarter turn around Trafalger Square shows that British traffic wardens have a relaxed view of modern marriage--here are two walk signs (or maybe go-ahead signs) that seem to celebrate both traditional and same-sex marriage.  (I was in a bit of a hurry so I didn't have time to circumnavigate the square and look for other variations on this theme...)

Rules of the road for cars and bikes

In many places where cars and bikes share a road, they customarily (if not legally) follow different rules. In England, a trial program will allow bikes to travel the wrong way down some one-way streets: Cyclists will be given green light to ignore one-way signs.

"Cyclists will be permitted to ride the wrong way along one-way streets under a change intended to encourage more people to give up their cars or use them less.
The Government will announce today that cyclists will be permitted to ignore no-entry signs: a practice already followed by many, including David Cameron, the Conservative leader.
The Department for Transport is authorising a trial in the Royal Borough of Kensington & Chelsea, Mr Cameron’s home authority in West London, in which a small plate saying “Except cyclists” will be attached to poles carrying no-entry signs.
If the trial is successful, the department intends to extend the policy to the rest of Britain and permit thousands of one-way streets to become two-way for bikes. It believes that long diversions around one-way systems are a significant deterrent to new cyclists, who might be less confident about breaking the rules."

On this side of the pond, Brookline MA is trying something similar, although not on the roads that I ride to work: Right way or wrong way? Brookline tries out new bike lanes

Lynne Kiesling at KP has a nice post on whether cars and bikes should obey the same rules of the road: Roads and paths as common-pool resources, and the problem of governing them

The rules of the road are a relatively recent invention: 2009 marks the 100th anniversary of Boston’s first traffic regulations, as issued by the Board of Street Commissioners. Peter DeMarco of the Boston Globe reports A century ago, driving laws tamed Boston’s wild streets.

"Back then there were no street signs, no stop signs, no traffic lights, no double center lines, no traveling lanes, and no yield signs. Automobiles had to battle horse-drawn carriages and wagons, bicyclists, trolleys, and pedestrians for space on the road. And while we joke today about how infrequently we obey traffic laws in Massachusetts, a century ago, there were scarcely any laws to obey."

Of the new laws adopted in 1909 he says:"A number of the laws are still very much in use today. Boston got its first one-way streets, adopted a new rule requiring drivers to “signal if about to turn,’’ and began requiring drivers to pass on the left - all in 1909. Parking within 10 feet of a curb was prohibited, double parking was outlawed (well, at least on paper), and police, fire, and other emergency vehicles (including postal carriers and doctors) were given the right of way.
But the rules also show how little our state’s first motorists actually knew about driving, and how Boston streets were really a free-for-all. Drivers had to be told not to stop in the middle of the street, not to park on sidewalks, and not to drive in reverse. The regulations include basic diagrams, reprinted in newspapers for all to study, explaining how to properly make a right turn, a left turn, and a U-turn - revolutionary stuff in 1909, when license exams consisted of a paltry 12 questions."
...
"Most cars were rudimentary, lacking not only turn signals, brake lights, and treaded tires, but also speedometers, windshields (thus the need for driving goggles), roofs, shock absorbers, power steering, and heat (necessitating leather driving coats and gloves). Steam-engine cars could explode, while hand-crank starter rods could spin back and break your arm. To apply brakes, you pulled hard on a lever. Seat belts, alas, didn’t exist."

Update: a column in the London Times suggests that bike riders will have to become more law abiding if London is to become more like Amsterdam, with high volume bike traffic: Time’s up, bike bandits

Coming of Road Rage in Samoa

Unless the government backs down, Samoa will change from driving on the right to driving on the left (British Commonwealth style) on September 7:

Shifting the Right of Way to the Left Leaves Some Samoans Feeling Wronged
Government Calls Traffic-Rule Switch 'Common Sense,' but It Sparks Road Rage.

This is one of those cases in which it clearly helps everyone to have a clear rule about which side of the road to drive on, and a little government regulation (and even inter-government coordination) can promote efficient traffic flow. (Think of the congestion at the borders at which you had to switch from driving on one side to driving on the other.)

But it isn't obvious that there's a "right" side, especially since Samoa is an island, and doesn't have to coordinate with anyone who can drive to Samoa from somewhere else. (The last country in continental Europe to switch sides--from driving on the left to driving on the right--was Sweden, in 1967.) Here's a nicely written historical account (whose accuracy I can't vouch for): Why do some countries drive on the right and others on the left ?

(I particularly liked their description of the decision in Pakistan: "Pakistan also considered changing to the right in the 1960s, but ultimately decided not to do it. The main argument against the shift was that camel trains often drove through the night while their drivers were dozing. The difficulty in teaching old camels new tricks was decisive in forcing Pakistan to reject the change.")

The government of Samoa believes that the benefits of switching will come from enabling Samoans to buy used cars from the left-driving Australians and New Zealanders.

But the proposal to switch sides is not without costs, since the current stock of cars has the driver sitting on the left, which will make some things (like passing) harder if traffic is switched to the left side of the road. (And of course the current stock of school buses will have to load and unload children from the middle of the street, instead of from the curb.)

It looks like September 7 might be a good day to avoid the roads, if you happen to be in Samoa. (And here's an earlier post on New Zealand traffic rules .)
*********

Update: Samoa switches smoothly to driving on the left
"Samoa is the first country in decades to change the direction of traffic. Iceland and Sweden did it in the 1960s, and Nigeria, Ghana and Yemen did it in the 1970s."

Behavioral game theory on the MA Turnpike

A recent story in the Boston Globe sounds like a behavioral economics seminar on transaction costs: why are a third of the tolls on the Massachusetts Turnpike still paid (more slowly and expensively) in cash, rather than using the (now free) transponders?
Some still slow to make the move to Fast Lane: 1 in 3 tollpayers paying at booth
"The Massachusetts Turnpike Authority has made strides in signing people up to use Fast Lane, with 66 percent of tolls now paid electronically, up from 62 percent in January. But the 34 percent who use cash, and pay higher tolls at booths inside Greater Boston to do so, remain a bit of a mystery."
...
"The survey LeBovidge conducted found that the biggest hurdle to signing up more people used to be cost, accounting for about 75 percent of the abstainers. About 7 percent worried about handing personal data to the Turnpike Authority or having their movements tracked. Some remaining drivers - not reflected in the survey - come from out of state and might not have an E-Z Pass account usable in Massachusetts. Other commuters do not have a checking account or credit card.
...
"If they wait in cash lanes enough times, most technophobes get converted. Fast Lane usage at the Allston-Brighton booths rises to 86 percent during morning rush hour into Boston. Massive traffic jams also do the trick: The Easter backup helped drive signups to 45,905 in May, compared with 10,875 during the same month last year."

One reason this is an interesting problem is that it's not just about individual choice, there's an element of behavioral game theory in this kind of slow learning. Cash payers produce congestion--negative reinforcement--for other cash payers. When lines at the toll booths get really long, even the EZ Pass users have to wait on line to get to the toll booths. So slower payers provide a negative externality to everyone on the busiest days.

In a forthcoming paper in the QJE, Amy Finkelstein raises the possibility that those cash payers may also provide a small positive externality by being more politically sensitive to changes in the tolls: EZ-Tax: Tax Salience and Tax Rates.
"Abstract: This paper examines whether the salience of a tax system affects equilibrium tax rates. I analyze how tolls change after toll facilities adopt electronic toll collection (ETC); drivers are substantially less aware of tolls paid electronically. I estimate that, in steady state, tolls are 20 to 40 percent higher than they would have been without ETC. Consistent with a salience-based explanation for this toll increase, I find that under ETC, driving becomes less elastic with respect to the toll and toll setting becomes less sensitive to the electoral calendar. Alternative explanations appear unlikely to be able to explain the findings."

So the next time you are stuck on the Mass Pike behind a long line of drivers waiting to pay their tolls, try to remember that there may be a small benefit to having the toll be so salient.

Market for electric cars

Before there's a very big market for all-electric cars, there would have to be a way to take long trips in them. For gas-powered cars, there's an extensive infrastructure of filling stations around the world's network of roadways. The NY Times reports on one company's plans to initiate such a network of stations, where you could change your depleted battery for a full one: Mapping a Global Plan for Car Charging Stations

"Mr. Agassi said the first 50 stations would be built in Israel by the end of 2010, the same time Renault’s electric cars would be introduced there, and followed by installations in Denmark, Hawaii and elsewhere. "

Israel and Hawaii seem like natural places to get electric cars started. Both of them are islands as far as auto traffic is concerned: very few people drive out of either one of them. So it should be possible to serve all the driving needs with a small, dense network. Denmark will be harder, since although many car trips that begin in Denmark remain in Denmark, Danes also can drive to Germany and Sweden, and from there on to the wide world, so a Dane with an electric car would, at least for a while, be more limited than one with a gas-powered car.

New Zealand traffic rules

Traffic rules are designed to avoid coordination failures. In much of the world, driving is on the right. New Zealand is one of the island nations in which driving is on the left, the next most popular choice. Uniquely, they have a rule that says drivers taking left turns (which, remember is the turn that doesn't cross traffic) must yield to drivers taking right turns. (Here's a site with a picture. If we had this rule in the U.S. it would mean drivers taking a right must yield to those taking a left.) Apparently this is an inferior coordination rule. On the one hand, a driver planning to take a right turn (across traffic) might appear to be planning not to turn. On the other, a driver planning a right turn who has precedence over a driver taking a left must still yield to a driver going straight, and so errors in signaling in either direction are a problem. So from time to time New Zealanders debate changing the rule: Quirky intersection rule set to face review - again

"AA motoring affairs manager Mike Noon said New Zealand's version was "most probably the most confusing and poorly understood rule that we have".
Although it was designed to reduce the risk of rear-end collisions for vehicles waiting to turn right, he believed that was outweighed by the hazards of side or head-on crashes.
One major hazard was when a vehicle swung right into the path of an opposing driver who might have inadvertently signalled a left-hand turn, but was continuing straight ahead."

Of course, switching from one equilibrium to another (even if superior) presents coordination problems of its own. Maybe September 3 should be Coordination Day, in memory of the day in 1967 when Sweden switched from driving on the left to driving on the right.

Congestion fees: "Lexus lanes" considered in UK

The Telegraph reports that British traffic authorities are considering allowing motorists driving alone to pay to be allowed to drive in less crowded lanes previously reserved for high occupancy vehicles: 'Lexus lanes' could be trialled within two years .

The automobile association finds this repugnant:

"The plans were condemned by the AA.
"Our members oppose them, they don't want to pay to use hot lanes," a spokesman said. "Why should people have to fork out to avoid congestion?" "