A revived debate: What role should police play in traffic safety? |MinnPost

Bill Lindeke wrote an excellent piece “A revived debate: What role should police play in traffic safety?” at MinnPost

IS A POST-POLICE STREET POSSIBLE?

Even with a groundswell of support, decoupling cops and traffic safety remains a key challenge. Police spend a large amount of their time dealing with problems associated with driving, mostly responding to crashes, which also ties up court systems. (See this anecdotefrom a judge in Washington state, claiming that 90% of their cases had to do with car accidents.)

“While it would be nice if our transport facilities were all self-enforcing, discouraging bad behavior through good design, we are nowhere near that yet,” replied David Levinson, when I asked him about this topic. Levinson, a civil engineering professor, headed the University of Minnesota’s Accessibility Observatory for years before moving to Australia to take a position at the University of Sydney.

Rethinking policing is not something new to Levinson. After the killing of Philando Castile in Falcon Heights during a traffic stop in 2016, Levinson wrote two posts on his blog outlining reforms to police enforcement of traffic rules. In them, he called for reducing racial bias in policing, through five potential changes like vehicle inspections, fine reform, and decreasing primary offenses.

But he remains skeptical about removing police altogether.

“I would say there needs to be some enforcement, but it does not need to be traditional police enforcement in the vast majority of cases,” he said. “Random enforcement, like police just hanging out looking for broken taillights, is unnecessary and there is no evidence that it increases safety. Similarly, programs targeting pedestrians are without evidence in improving safety, as far I have seen.”

AUTOMATED CAMERAS: GOOD OR BAD?

While most transportation advocates agree that traditional tickets are not the central solution to traffic safety, other enforcement approaches prove much more divisive. Most notably, automated speed and red-light cameras engender dramatically different reactions. On one hand, both Morris and Levinson believe they are a better solution than police, and point to studies in support of this approach.

“I have been studying automated speed enforcement (ASE) for many years and I still believe it is an effective alternative to in-person enforcement,” explained Morris. “There are still risks to automated enforcement regarding decision making on where to place cameras and how to implement a fee structure. Each decision could result in disproportional impacts or harm on minority populations if not done thoughtfully.”

According to Morris, speed cameras, like the ones deployed around New York City schoolsand in other countries, also reduce bias, so that white drivers are not more likely to be let off with a warning, and additionally pose “little risk of escalation or violence” by police officers.

It’s a sentiment shared by Levinson, who sees cameras as a solution: “There is strong evidence that photo enforcement of speeding and red-light running is effective, if also abused in different ways, notably as a cash cow, and deployment needs to not just be in poor neighborhoods.”

Comment: You can find lots of articles on the effectiveness of programs via Google Scholar.

Specific programs like sobriety checkpoints also are effective in catching and deterring impaired driving.

Why Australian road rules should be rewritten to put walking first

Published in The Conversation, reposted here:

You are walking east on a footpath and come to an unmarked intersection without traffic signals. A vehicle is driving north, across your path. Who has right of way in Australia?

Should you step into the road expecting the vehicle to slow down or stop if necessary? Is the driver legally obliged to do so?

And does the driver see you? How fast is the vehicle going? Can it stop?

Now imagine you are the driver. What will the person on foot do next?

So the answer to the question of “giving way” is complicated. It depends on the speed of the car, how fast the person is walking, how quickly the driver reacts to apply the brakes, the vehicle itself, road conditions and how far the car and walker are from each other. Ideally, both the driver and walker can assess these things in a fraction of a second, but human perception and real-time calculation skills are imperfect. At higher speeds, both pedestrians and drivers underestimate vehicle speed.

Soon we will have to seriously consider autonomous vehicles, which can assess distance and speed almost perfectly, but there is still that ambiguity.


Read more: Driverless vehicles and pedestrians don’t mix. So how do we re-arrange our cities?


What does the law say?

Road rules legislate how drivers should behave. But it turns out most people do not know right-of-way rules.

In Australia, the National Transport Commission recommends model rules, which each state adopts and lightly modifies. For instance, New South Wales Road Rules 72, 73 and 353 cover pedestrians crossing a road.

Rule 353 says:

If a driver who is turning from a road at an intersection is required to give way to a pedestrian who is crossing the road that the driver is entering, the driver is only required to give way to the pedestrian if the pedestrian’s line of travel in crossing the road is essentially perpendicular to the edges of the road the driver is entering – the driver is not required to give way to a pedestrian who is crossing the road the driver is leaving.

Because of the legal principle of duty of care, drivers must still try to avoid colliding with pedestrians. They have a legal obligation to not be negligent. Thus, they must stop if they can for pedestrians who are already there, but not those on the side of the road wanting to cross.

However, this element of the NSW Road Transport Act is not made explicit in the NSW Road Rules. There is no statutory requirement in the road rules or elsewhere to give way to pedestrians other than as set out specifically in the road rules.

In contrast, NSW Road Rules 230 and 236 explicitly require pedestrians to avoid behaving dangerously around cars.

The published advice in NSW is:

Drivers must always give way to pedestrians if there is danger of colliding with them, however pedestrians should not rely on this and should take great care when crossing any road.

Does a slow-moving person’s higher risk of being hit mean they can’t cross the road?Shutterstock

This statement is not supported by any road rule or other law.

Does the law as written mean a slow-moving person can never cross the street because of the risk of being hit? Only because duty-of-care logic indicates both the driver and pedestrian should yield to the other to avoid a collision is it possible for this person to cross without depending on the kindness of strangers. But the law gives the benefit of doubt to the driver of the multi-ton machine. Existing road rules permit drivers to voluntarily give way, or not.

Keep in mind the asymmetry of this situation. A person walking into the side of the car is silly. A car being driven into the side of a person, as happens 1,500 times a year in NSW, is life-threatening.


Read more: Pedestrian safety needs to catch up to technology and put people before cars


What do we recommend?

The UK Manual for Streets presents a street user hierarchy that puts pedestrians at the top. That is, their needs and safety should be considered first.

A recommended hierarchy of street users. Manual for Streets/UK Department for Transport

Walking has multiple benefits. More people on foot lowers infrastructure costs, improves health and reduces the number in cars, in turn reducing crashes, pollution and congestion. However, the road rules are not designed with this logic.

The putative aim of road rules is safety, but in practice the rules trade off between safety and convenience. The more rules are biased toward the convenience of drivers, the more drivers there will be.


Read more: How traffic signals favour cars and discourage walking


Yet public policy aims to promote walking. To do so, pedestrians should be given freer rein to walk: alert, but not afraid.

Like many things in this world, intersection interactions are negotiated, tacitly, by road users and their subtle and not-so-subtle cues. Pedestrians should have legal priority behind them in this negotiation.

The road rules need to be amended to require drivers to give way to pedestrians at all intersections. We favour a rule requiring drivers to look out for pedestrians and give way to them on any road or road-related area. In the case of collisions, the onus would be on drivers to show they could not in the circumstances give way to the pedestrian.

We believe all intersections without signals – whether marked, courtesy, or unmarked – be legally treated as marked pedestrian crossings. (It might help to mark them to remind drivers of this.) We should think of these intersections as spaces where vehicles cross an implicit continuous footpath, rather than as places where people cross a vehicular lane.

At this intersection in Surry Hills, NSW, vehicles cross a continuous footpath. Photo by David Levinson., Author provided

This change in perspective will require significant road user re-education. Users will have to be reminded every intersection is a crosswalk and that pedestrians both in the road and showing intent to cross should be yielded to, whether the vehicle is entering or exiting the road. We believe this change will increase safety and willingness to walk, because of the safety-in-numbers phenomenon, and improve quality of life.

In Minnesota, every corner is a crosswalk, marked or not, so stopping for pedestrians at intersections is mandatory, whatever direction the car is moving. Minnesota Department of Transportation., Author provided

Drivers should assume more responsibility for safety

People should continue to behave in a way that does not harm themselves or others. People on foot should not jump out in front of cars, expecting drivers to slam on their brakes, because drivers cannot always stop in time.


Read more: Nothing to fear? How humans (and other intelligent animals) might ruin the autonomous vehicle utopia


Similarly, drivers should be ready to slow or stop when a person crosses the street, at a crosswalk or not. But the law should be refactored to give priority to pedestrians at unmarked crossings. This will reduce ambiguity and make drivers more alert and ready to slow down.

In tomorrow’s world of driverless and passengerless vehicles, the convenience of drivers becomes even less essential. If someone is crossing the road, most of us probably believe a driverless vehicle should give way to ensure it doesn’t hit that person for two reasons: legally, to avoid being negligent; and morally, because hitting people is bad, as identified in many examples of the Trolley Problem.

Further, we should think more like the Netherlands, where vehicle-pedestrian collisions are presumed to be the driver’s fault, unless it can be clearly proven otherwise.


Read more: The everyday ethical challenges of self-driving cars


This article examined a few of 353 distinct road rules. Many others affect pedestrians and should also be re-examined.


This article was extensively edited by Janet Wahlquist of WalkSydneyand extends some ideas developed as part of Betty Yang’s undergraduate thesis, but the text is the sole responsibility of the author.

Pedestrian safety around light rail a balance: transport experts | Canberra Times

Finbar O’Mallon writes for the Canberra Times “Pedestrian safety around light rail a balance: transport experts“. I get quoted …

A pedestrian was struck by a light rail vehicle at the intersection of Northbourne Avenue and Barry Drive on Saturday morning.

University of Sydney transport expert David Levinson said in European cities trams shared the streets with pedestrians.

“It’s not a problem. Part of it’s the speed and the expectation,” Professor Levinson said.

But Professor Levinson said at Northbourne Avenue, pedestrians were crossing six lanes of traffic and now two tracks.

“That’s eight different points where someone can come in and hit you and you’re trying to make the decision before that happens,” he said.

“That’s a complicated thing for a human to do.”

He also suggested having one consistent green light for pedestrians when crossing Northbourne so they could travel across the entire avenue instead of having to stop midway.

“Cars don’t have to stop halfway through the intersection, why would pedestrians need to?” Professor Levinson said.

Professor Levinson also warned against overloading the network with safety warnings.

“You put a sign everywhere, no sign means anything. You put a sign nowhere and no one has any information,” Professor Levinson said.

Professor Levinson said getting it right was a balance.

Putting up fences risked making it too restrictive for pedestrians, having safety supervisors at major intersections would be too expensive in the long term and loud warning horns would disturb people living in or using the area, he said.

“You want this to be a self explaining experience for the pedestrian.”

Obviously the local engineers on the project, in consultation with the community, will have to consider the alternatives and site in-depth, and test various strategies. This is an issue many LRT systems face, including those in Minneapolis and St. Paul, and I expect the City and Southeast Light Rail in Sydney.

Eleven Sydney council areas where pedestrians die more than motorists

Nigel Gladstone in the Sydney Morning Herald wrote “Eleven Sydney council areas where pedestrians die more than motorists“. I got some choice quotes:

Professor of transport at the University of Sydney David Levinson said changing the way Sydney’s traffic signals give priority to cars over pedestrians in busy areas was one way to stem the flow of injuries.

“This inequality [in traffic light phasing] undermines many of the stated goals of transport, health and environment policy,” Professor Levinson said. “Creating an environment that is better for pedestrians with separated footpaths, easy and frequent safe road crossings, generally slower cars and trucks, better trained and more law-abiding drivers (via police enforcement) will reduce the likelihood of fatalities.”

Road deaths have been increasing in both NSW and the US recently, while most other OECD nations are reporting fewer fatalities.

One theory [Referring to: Chi, Guangqing, Jeremy Porter, Arthur Cosby and David Levinson (2013) The Impact of Gasoline Price Changes on Traffic Safety: a Time Geography ExplanationJournal of Transport Geography 28 1-11. [doi] ] is that as more people can afford to be on the road, drivers with less experience, who tend to be younger, and therefore more dangerous, are added to the mix of motorists.

“When there’s economic expansion, people are working more hours and they probably get a bit more aggressive,” Professor Levinson said.

Research [by Wes Marshall] comparing Australian and American drivers found the rate of fatalities was more than twice as high in the US, where more than half of drivers do not stop or yield to pedestrians at crossings.

In Hawaii’s capital Honolulu, fines for pedestrians who text while crossing the road at traffic lights began this year.

In the City of Sydney, one in three people crossing the road is using a mobile phone and it’s time pedestrians “start owning this problem as well”, Pedestrian Council chief executive Harold Scruby said.

“Pedestrian deaths and serious injuries are going through the roof,” Mr Scruby said. “There is nothing that we’re seeing that the government is doing to help pedestrians.”

Hitting pedestrians with a $200 fine for using a mobile phone while crossing the road, even on the green man phase, is on Mr Scruby’s agenda.

“There’s no barrier there just because the light’s green. Half of the drivers coming towards you are on the phone too,” Mr Scruby said. “If you’re hit as a pedestrian, the driver will be automatically drug and breath tested but that’s a box they [police] have to tick, no one then goes looking for the mobile phone, there’s no box to tick.”

Professor Levinson said fining pedestrians was “basically a form of victim blaming”.

“Distracted pedestrians don’t kill drivers or passengers. Distracted drivers kill pedestrians,” he said. “Deaths are due to high speed and high mass, and drivers of two-tonne machines have an obligation to be more alert.”

In the three years to 2017, one pedestrian was killed and 25 were seriously injured while distracted by a mobile phone. But this is likely to be an under-reported issue, as it relies on witnesses telling police and other forms of evidence.

There are no plans to introduce penalties for people using mobile phones while crossing roads in NSW, a Transport for NSW spokesman said.

 

I also got to be ABC Radio Illawarra Friday Morning (talking about traffic safety), and ABC Radio Adelaide Friday Afternoon (talking about Beg Buttons) (first few minutes of this).

Are Australian Vehicles Getting Bigger?

ABC Radio Sydney called me and asked essentially:

`Are Australian Cars Getting Bigger?’

The short answer is ‘No.’

AustralianNewCarMarket.003

Using data from the Federal Chamber of Automotive Industries that was once freely available online, and is now behind a paywall, I have produced graphs illustrating the Australian vehicle market.  The data show among the passenger cars: medium, small, light, and micro are all gaining in proportion of passenger cars, rising from half the passenger car market to 83% since 2000.

But

`Are Australian Vehicles Getting Bigger?’

The answer here is ‘Yes.’

As will be no surprise to Australians, or North Americans (See Canada data), the share of Sports Utility Vehicles has exploded since the beginning of the Millennium from about 13% to 39%, and now more SUVs are sold each year than passenger cars.

AustralianNewCarMarket.001

AustralianNewCarMarket.002

This trend, which mirrors that in the US, helps explain Ford’s recent decision to exit most of the passenger car business in the US.

Now 50%  of 70% is 35% (small cars share of all vehicles in 2000) while 80% of 38% is 30% (small cars share of all vehicles in 2017), so the share of small and medium cars of all vehicles is falling. But the total market of vehicles sold in Australia is still increasing from 787,000 in 2000 to 1,189,116 in 2017, and 30% of cars sold in 2017 is more than 35% of cars sold in 2000, so there are still more in terms of total number of small and medium cars sold in 2017 in total than 2000, even if it is a declining share of the market.

The Australian government also conducts a Motor Vehicle Census and just as the number of new cars sold each year rises with population growth, the total number of vehicles is also rising. This differs from the US, which has more or less peaked in cars per capita, and perhaps cars. I graphed this data for NSW for selected years (this data, is also, inconveniently, not in one place)

AustralianNewCarMarket.005

The reason for more SUVs vs. large cars are speculative. That is, why do people now prefer SUVs and not station wagons or big cars? It’s not as if people actually do a lot of off-road driving.

One is the idea of the extreme trip. Sometimes (say once a year or even once a month) a very large car would be useful. So instead of renting the specific vehicle when they want it, SUV-owners buy the vehicle they would use 1% of the their trips (or 0.05% of their time – since cars are only used 5% of the day anyway, and at rest the remainder, sleeping more than even cats), but which is too large 99.95% of the time.

One answer is the car Arms Race. In a taller car, the driver can see farther ahead (drivers are less likely to have their view obscured), which lets tall vehicle drivers anticipate better. It makes drivers feel safer, which they are for themselves, even when they are not for others.

More people are killed because of SUVs and light trucks, in the US, Michelle White estimated in 2004 “For each 1 million light trucks that replace cars, between 34 and 93 additional car occupants, pedestrians, bicyclists, or motorcyclists are killed per year, and the value of the lives lost is between $242 and $652 million per year.” Presumably the same logic holds in Australia.

Increasing the mass of vehicles on the road doesn’t do society any favours from an energy consumption, or air pollution perspective either. And of course, larger vehicles use more space, consuming more land in parking lots (which are now often restriped to accommodate more massive vehicles) and roads, where the width of lane consumed by larger cars rises, providing less manoeuvrability for other cars.

With the rise of autonomous vehicles, and especially vehicle sharing, the right sized vehicle will be summonable by app, so when travelers need the specific type of car for a large trip with many people, they can get it. The rest of the time, drivers will be able to use a car fit for purpose, one that holds one person for a one-person trip, and two people for two-person trips, and so on. This opens up the potential for skinny cars, enclosed electric cycles, and many other appropriate vehicles, which take up less road space, making it even easier to improve the environment for other road users, including walkers and bicyclists.

Toyota iRoad one-passenger concept cars, image courtesy Toyota.
Toyota iRoad one-passenger concept cars, image courtesy Toyota.

DEFINITIONS:

Passenger Motor Vehicles Passenger vehicles are classified dependent on size, specification and average retail pricing. Selected vehicle types will be assessed on footprint defined as length (mm) x width (mm), rounded, as follows:
Sports Utility Vehicles Vehicles classified as Sport Utility Vehicles (SUV) meet the FCAI criteria for classifying SUV vehicles based on a 2/4 door wagon body style and elevated ride height. Vehicles typically will feature some form of 4WD or AWD, however, where a 2WD variant of a model is available it will be included in the appropriate segment to that model.
Light Trucks Vehicles designed principally for commercial but may include designs intended for non-commercial applications.
Heavy Trucks Vehicles designed for exclusive heavy commercial application.

Car sizes:

Micro Hatch, sedan or wagon with a footprint < 6,300
Light Hatch, sedan or wagon with a footprint range 6,301 – 7,500
Small Hatch, sedan or wagon with a footprint range 7,501 – 8,300
Medium Hatch, sedan or wagon with a footprint range 8,301 – 9,000
Large Hatch, sedan or wagon with a footprint range 9,001 – 9,500
Upper Large Hatch, sedan or wagon with a footprint range 9,501 >
People Movers Wagon for passenger usage, seating capacity > 5 people
Sports Car, coupe, convertible or roadster

SUV Sizes:

Light Duty 3,501 – 8,000kg GVM
Medium Duty => 8,001kg GVM & GCM < 39,001
Heavy Duty 8,001kg GVM & GCM > 39,000

Light Truck Sizes:

Light bus < 20 Seats 8+ seats, but less than 20 seats
Light Bus > 20 Seats 20+ seats
Vans/CC <= 2.5t Blind/Window vans and Cab Chassis <= 2.5t GVM
Vans/CC > 2.5–3.5t Blind/Window vans and Cab Chassis between 205 and 3.5 tonnes GVM
Pick-up / Chassis 4×2 Two driven wheels, normal control (bonnet), utility, cab chassis, one and a half cab and crew cab
Pick-up / Chassis 4×4  Four driven wheels, normal control (bonnet), utility, cab chassis, one and a half cab and crew cab

Heavy Truck Sizes:

Light Duty 3,501 – 8,000kg GVM
Medium Duty => 8,001kg GVM & GCM < 39,001
Heavy Duty 8,001kg GVM & GCM > 39,000

Cage the Automobile

Is the purpose of bollards to keep people in or keep cars out? A reader writes:

 

Bollards done wrong, Egypt.
Bollards done wrong. It’s a long pedestrian street, would you bollard the entire street,  because they are proposing low risers. You will end caging the people like in Egypt.

After the attack in Toronto last week with a guy driving a van and killing 10 people and injuring 15, Montreal announced a new plan for Saint Catherine street making it pedestrian friendly, with a nice wide sidewalk showing young people walking, yet  when the mayor was asked if they planned for pedestrian safety from such attack she said ‘no, we did not.’

So the moral question: should we change our planning for pedestrians to ensure safety from a crazy person in a van, terrorists, drunk drivers,  just incapacitated drivers. This is not the first, and will not be the last, time a driver plows down pedestrians. By doing so we show weakness to terrorists? Are we converting the outdoors to a Zoo placing pedestrians in cages. Should the woonerf, for example, be like an open zoo.

It’s a moral and ethical question how much separation should we have in an era when crazy people uses cars as weapons to kill random humans. How many incidents and deaths will it take to change the approach for pedestrian environments to make it as safe as air travel.  If we  add more small obstacles, how much will they spoil the pedestrian environment and sense of freedom.

 

The crazy person in a van problem is only going to get worse with automation and especially connectivity, a remote control car bomb is even easier than a suicide.

This Delft Bollard is a casualty of the Car Wars.

In my view, cars should be in the cages, the people should be free. And then the cages need to be made smaller and smaller.

All urban streets in heavily pedestrian trafficked areas should have bollards or equivalent to keep the cars away from the people. Woonerfs are fine for residential streets, and if people want to encroach on shared space that is also fine, but cars should not encroach on people space. Just as we don’t let cars in most buildings, there should be outdoor public spaces where they are also prohibited.

We don’t need fences or chains like in the photo of Egypt, just lots of posts (trees, bike racks, benches, bus stops, street furniture, planters etc.) that make it impossible for a car to run down the sidewalk or into buildings. This furniture of course should not interfere with the free flowing movement of people, and might require taking lanes from the storage, or even movement, of cars. As with all good urban design, examples of this are in Delft, with some lowerable Bollards to allow service, emergency, and freight vehicles in when needed.

 

Delft defining Pedestrian domain.

Delft, lowerable Bollards on a bridge

 

 

 

 

 

Safety in Numbers: Pedestrian and Bicyclist Activity and Safety in Minneapolis

Recent Report:
AbstractThumbnail
This investigation aims to evaluate whether the Safety in Numbers phenomenon is observable in the midwestern U.S. city of Minneapolis, Minnesota. Safety in Numbers (SIN) refers to the phenomenon that pedestrian safety is positively correlated with increased pedestrian traffic in a given area. Walking and bicycling are increasingly becoming important transportation modes in modern cities. Proper placement of non-motorized facilities and improvements has implications for safety, accessibility, and mode choice, but proper information regarding estimated non-motorized traffic levels is needed to locate areas where investments can have the greatest impact. Assessment of collision risk between automobiles and non-motorized travelers offers a tool that can help inform investments to improve non-motorized traveler safety. Models of non-motorized crash risk typically require detailed historical multimodal crash and traffic volume data, but many cities do not have dense datasets of non-motorized transport flow levels. Methods of estimating pedestrian and bicycle behavior that do not rely heavily on high-resolution count data are applied in this study. Pedestrian and cyclist traffic counts, average automobile traffic, and crash data from the city of Minneapolis are used to build models of crash frequencies at the intersection level as a function of modal traffic inputs. These models determine whether the SIN effect is observable within the available datasets for pedestrians, cyclists, and cars, as well as determine specific locations within Minneapolis where non-motorized travelers experience elevated levels of risk of crashes with automobiles.
Recent publications from this report include:

Speed vs. Safety

March 21 [Updated with more accurate estimate/figure after fixing an excel bug] How fast should we drive? From a social cost perspective, faster speeds save time, which has a value, but faster speeds cost lives, which also have a value. To illustrate the trade-off I did some back of the envelope calculations, imagining, like a macro-economist, a single road represents the whole t

Speed vs. Safety (updated)
Speed vs. Safety (updated)

ransport system. Annually there are about 30-40,000 people killed in the US, there are an annual Vehicle Miles Traveled of 3,208,517,000,000. The average speed of travel isn’t known directly, but if we assume the average person travels in a car 60 minutes per day (the 1 hour travel time budget) this implies, at approximately 30 miles of travel per day per traveler, about 30 MPH, which seems about right (including 1/4 of travel on freeways at higher speeds and 3/4 on surface streets and roads at lower speeds, and including traffic signals). As the saying goes, Your Mileage May Vary, and this is intended to be indicative — not a universal answer. Some additional assumptions:

  • We take the Value of Life to be $10,000,000, and assume fatalities are the only cost associated with crashes (they are about 78 % of total crash costs according to our analyses, so we should inflate this number to get total crash costs) [US DOT says $9.6 M]
  • We take the Value of Time to be $15/hour [US DOT gives a lot of ranges, but this number is high for all surface travel excluding freight]
  • We assume the number of deaths drops linearly with speed, to zero at zero MPH. The improvement is likely non-linear, as reductions in speeds from high speeds are more valuable than from low speeds.
  • We assume the value of travel time savings is constant, independent of the amount of time saved.

To be clear, these are huge assumptions. Examining the figure we see the lines cross at about 75 MPH, which is the minimum total cost. So why don’t we set the speed limit to  75MPH? Note that:

A Political Economy of Access: Infrastructure, Networks, Cities, and Institutions by David M. Levinson and David A. King
A Political Economy of Access: Infrastructure, Networks, Cities, and Institutions by David M. Levinson and David A. King
  • Travel time savings are, while still speculative in terms of their valuation, both private and real,
  • The statistical value of life is far more abstract. The value of my life to me is infinite. The value of your life to me is, sadly, not. Yet, I am willing to take risks that increase the probability of my dying in order to save time or earn more money. These are the kinds of factors that allow an estimate of value of a statistical life.
  • Death and crashes are probabilistic affairs, while the time lost is deterministic. People are gamblers.
  • There are some other benefits to faster travel not accounted for, such as more or longer trips (to better destinations, or the ability to get better real estate at the same price), which increase consumer surplus. The analysis here does not consider user response to lower speeds, which would be to travel less (or higher speeds and travel more).  There are also issues like travel time reliability.
  • Since 1988 The Statistical Value of Life has risen 6-fold in US DOT estimates, the value of time has little more than doubled. (If we cut the value of life to $3M, (effectively holding the tradeoff more similar to 1988 levels), the tradeoff is much higher .)
  • Speed limits reflect what travelers will travel at, not what we wish they would travel at.

If you dislike these number, you can roll your own analysis on individual roads. The difficulty is not measuring the speed of those roads, but measuring their safety. There is a Highway Safety Manual for such purposes, but crashes are highly random events.

UPDATE 2: Axel Waleczek made an interactive Tableau, so you can test your own scenarios.

Additional Readings

Uber’s self-driving car killed someone today

Uber’s self-driving car killed someone today. This is terrible tragedy, and in retrospect, it will probably be judged to have been preventible. Future versions of the software will better address the scenario that led to this crash. But mistakes are how people and systems learn, and someone was going to be the first. The victims are scarcely remembered.

A few key points.

  • The safety rate for Uber AVs collectively is now worse than that for human drivers (1.25 pedestrian deaths / 100MVMT) (MVMT = Million vehicle miles traveled) (Uber is at about 1 MVMT, Waymo at about 4MVMT). It will undoubtedly get better.
  • Don’t assume Uber AVs are the same as Waymo or others. Different software, vehicles, sensors, driving protocols, safety cultures. The stats for each will differ.
  • Also we need to see the full investigation (from NHTSA, NTSB).
    • How much victim blaming will there be?
    • Was it just sadly unavoidable?
    • Or was it preventable?
  • The opposition will use this to bang on against AVs while supporters will be quiet for a while.

Hopefully the developers learn something and this type of crash is rare. Other AV makers will take the scenario and run it through their own simulations and field tests.

Still the technology trajectory is strong, and even if the US slows down development, it’s a big world. China won’t slow down development.

How Railways Dealt With The First Notable Fatality:

The Liverpool and Manchester Railway killed former Leader of the House of Commons and cabinet member, William Huskisson during the opening day ceremonies. It was the UKs 2nd significant steam railway and the first that was opened with a big deal with   such publicity. We write in The Transportation Experience

On September 15, 1830, the opening ceremonies for the Liverpool & Manchester Railway were held. The Prime Minster (the Duke of Wellington), Cabinet members, Members of Parliament, and other assorted dignitaries were present. Among those were an MP from Liverpool, and a 60 year old former Leader of the House of Commons and cabinet member, William Huskisson. The dignitaries had been riding on a train pulled by one of Stephenson’s Rockets. Reports differ, but Lady Wilton, an observer on the same train wrote to Fanny Kimble:

The engine had stopped to take a supply of water, and several of the gentlemen in the directors’ carriage had jumped out to look about them. Lord Wilton, Count Bathany, Count Matuscenitz and Mr. Huskisson among the rest were standing talking in the middle of the road, when an engine on the other line, which was parading up and down merely to show its speed, was seen coming down upon them like lightening. The most active of those in peril sprang back into their seats; Lord Wilton saved his life only by rushing behind the Duke’s carriage, and Count Matuscenitz had but just leaped into it, with the engine all but touching his heels as he did so; while poor Mr. Huskisson, less active from the effects of age and ill-health, bewildered, too, by the frantic cries of `Stop the engine! Clear the track!’ that resounded on all sides, completely lost his head, looked helplessly to the right and left, and was instantaneously prostrated by the fatal machine, which dashed down like a thunderbolt upon him, and passed over his leg, smashing and mangling it in the most horrible way.

Stephenson personally helped Huskisson onto a locomotive and traversed 15 miles in 25 minutes (57.9 km/h) to receive medical attention in the nearby town of Eccles. But it was for nought. Huskisson amended his will and died within the hour. (Garfield)

This was not the first death by steam locomotive, it was at least the third, but it was still the most notable. Wikipedia notes

5 December 1821, when a carpenter, David Brook, was walking home from Leeds along the Middleton Railway in a blinding sleet storm. He failed to see or hear an approaching train … and was fatally injured.” — Richard Balkwill; John Marshall (1993). The Guinness Book of Railway Facts and Feats (6th ed.). Guinness. ISBN 0-85112-707-X.

According to parish council records, a woman in Eaglescliffe, Teesside, thought to be a blind beggar, was “killed by the steam machine on the railway” in 1827– “Corrections and clarifications.” The Guardian. 2008-06-21. Retrieved 2009-02-05.

Despite this inauspicious beginning, both passengers and freight services (the latter opened in 1831) were immediate successes.