Tuesday, January 6, 2015

Hydraulic Autoism and Death at 30mph: Twenty is Plenty

The day after Christmas, a driver struck and killed a man attempting a mid-block crossing on Summer Street NE in the Grant neighborhood shortly after dark:
At approx. 5:27pm., Friday, 12/26/14; Salem Police responded to a vehicle vs pedestrian traffic crash on Summer St. NE near E St NE. On arrival of police, fire and medics it was determined that the pedestrian was deceased at scene.

The name of the deceased is being with held pending notification to next of kin.

The driver of the vehicle was identified as Guadalupe GARCIA, 42yrs of Salem. Garcia was operating a 2014 Chevrolet Camaro.

The investigation revealed that Garcia was traveling south on Summer St. NE, which is a two lane, 30mph, one way street, near E St. NE. As Garcia continued driving south of E St. NE approx 25 yds., the pedestrian walked out into the path of her vehicle and was struck.

Garcia remained at the crash scene and is cooperating with Traffic Control Unit investigators. There is no indication of any impairment of Garcia, the driver. Nor is there any indication of excessive speed involved.

Summer St. NE was re-opened for normal traffic flow at 9:00pm.

Once next of kin notification of the deceased has been made, an update press release will be sent out.
Last night police identified the man and have asked for help with next of kin:
Traffic Unit investigators have released the name of the pedestrian who was struck and killed in a traffic crash which occurred at 5:27pm Friday, 12/26/14 on Summer St. NE near "E" St. NE. The deceased pedestrian has been identified as Michael Allen Johnson, 63 yrs., (dob: 02/25/1951), a white male adult. All avenues in attempting to notify next of kin have been unsuccessful. Should anyone have any information concerning Michael Johnson's next of kin or a relative are asked to call the Salem Police Traffic Unit at 503-588-6171.
There is much we don't know. It seems likely he was doing what we now call "jaywalking," but even if the person on foot was walking very carelessly, a crash at the ostensibly "modest" and legal speed of 30mph has killed a man, and reminds us why we should consider an urban speed limit of 20mph.

For long we have known speed exponentially compounds catastrophe in crashes.

1940s Stopping Distance Poster
Iowa State Safety Council
(credit unknown)

2000s Stopping Distance Poster - City of Portland

Odds of fatality by speed:
20mph - 5%
30mph - 40%
40mph -80%
National Highway Traffic Safety Administration
The difference between the odds of dying in a 20mph crash and in a 30mph crash are startling: An increase of fully one third, from 5% to 40%, and doubling to a near certainty at 40mph!

Speed kills, and we have a system that unfairly punishes the errors of people on foot.

Our roads are designed to forgive and protect a 10mph error by a person in a car. Our roads and legal system routinely permit deaths at 30mph when people on foot make a mistake. As long as there is no impairment and no speeding, the death is legal and an acceptable cost for using the roads.

This is not a just and safe transportation system. This is a pure expression of pedestrian impedance and hydraulic autoism.

A Different Crash, Friday the 19th

Here's another one.

You might recall this crash. From the paper:
Two people suffered head injuries in a pedestrian-involved crash in downtown Salem early Friday morning.

Salem Police responded to the incident at 12:03 a.m., said Sgt. Mike Johnson.

Their investigation found that two people, an adult woman and a 12-year-old boy, were leaving the downtown movie theater and crossed the crosswalk at Marion and High streets NE when a vehicle struck them.

Both victims were taken to Salem Hospital, the woman with a head injury and the boy with an ankle injury. However, the boy was later diagnosed with a head injury and flown by Life Flight to Oregon Health and Science University, Johnson said.

Police said the driver involved in the crash was compliant at the scene and did not appear to be impaired.

No citations were issued and the investigation into the crash is ongoing.
4245 Drivers Daily Speed
by More than 10mph -
They do not Die

You may recall some of speed data from the middle Commercial study. At one count site, 4245 drivers daily speed more than 10mph over the posted limit.
Speeding is a problem here
Do we really 14 foot travel lanes?
Presentation Slides, Dec 11th
The reason 15% of drivers are speeding and going more than 10mph over the posted limit is because the road is broad and gently curved, the lanes are wide, there are few stop lights, and the road is engineered to accommodate speeding drivers. They rarely die.

The road is not engineered for people on foot and on bike; they are interlopers and when they make mistakes they pay disproportionately.


Salem Breakfast on Bikes said...

Ha, ha! by email a reader takes us to task for mathematical imprecision - even error.

They write, "from 5% chance of fatality to 40% is 800% increase, not one-third."

And they are right in this.

But that's not how I think of the magnitudes. A certainty is an odds of one, 100%. So the difference between 40% and 5% is about a third. It goes from a small chance to nearly a 50/50 toss-up. I think of it in terms of addition or subtraction, not multiplication.

The reason for this, is n=1, there is only one trial in a crash. It's not like you get yourself in n=1000 crashes and determine that 402 of them resulted in your death at 30mph, close enough to the expected value of 40%.

As probability the n=1 thinking is mathematically wrong, but I don't experience in this n=1 context an 8x increase in my sense of risk.

So - an interesting reminder about the too-frequent disjunction between the subjective experience of risk and its mathematical, actuarial expression.

It's bad math, but I'm sticking with it for qualitative reasons!

Anonymous said...

Consider hopping off the podium you call a bicycle for a minute...

There are two sides to every story. This was a case of suicide by car as reported by neighbors in the area. Perhaps we should consider the feelings of the woman who "hit" him. She will probably be affected by the incident for the rest of her life.

Salem Breakfast on Bikes said...

Your point is reasonable and important. I had considered this, but in the absence of additional public information, it seemed best to write about "carelessness" or "mistakes" by people on foot.

If this is a suicide, as you say the situation is even more complicated. And you are right, a driver who becomes involuntarily an instrument of another's suicide deserves great consideration.

But the issue isn't whether the driver is guilty. Based on the available public information, plainly in our current system she is blameless - driving the speed limit and having to contest with a mid-block "jaywalk" crossing in a zone that was not well lit by street lights.

The point that I wish to make is that at 20mph, a crash is much less likely to be fatal, and if what you say is true, the person might not have been successful killing themselves in this way. At 20mph, it is less likely a driver acting in accordance with the legal driving environment would kill a person perhaps intent on self harm. At 20mph, the driver may have been able to take a safe measure of evasive action, or to be able to stop in time.

Especially in an urban environment, a slower speed protects both the person on foot and the person behind the wheel.

We have this idea that driving a car is risk-free. But in fact driving a car is very dangerous, involving lethal forces, and we need to think seriously about the ways our transportation system fails to take adequately into account the fact that using a car too often entails death. We have a system that also fails drivers who think they are driving safely.
I would also draw your attention to the crash on Swegle, where in a 35mph zone, a child was killed.

Here on Summer Street, it could have been a child scampering into the street.

The point here is independent of questions of intention, about whether the death was also a suicide. At 30mph, thoughtless kids or thoughtful despondent adults are equally vulnerable to increased odds of death.

So I hope you don't read this as blaming the driver in a direct way. Based on the public information, no one would conclude the driver was morally wrong. I am blaming a transportation system that creates conditions in which a driver acts "reasonably" and "legally" and events still result in death. I am blaming a situation that calls 30mph "safe" when it is not as safe as we might think. We have a system problem, not driver culpability here.