drivers

Wanting to Drive and Quality of Driving

| David Levinson
The Chevy Vega
The Chevy Vega

Our society has undergone many subtle and not-so-subtle changes in the past few decades. Among those related to driving, safety, and perceived safety, I believe there have been lasting effects.

When I was growing up, and I went for a ride with my mom, I would sit in the front seat of the car. I would wear a seatbelt (a habit formed because of the seat-belt ignition interlock on our Chevy Vega preventing the engine from starting without seat belts (a one-year experiment reviled by the driving public). My children sit in the back seat because of the rise of so-called child safety seats and air bags.

When I was growing up, I would walk down the block alone in pre-school and Kindergarten, and around the neighborhood by 1st grade, and all over town by 3rd grade. I would ride the ColumBus by 4th grade with my Package Plan card (giving me free rides in on the system, a benefit which has since been removed). Today there is a movement for Free Range Kids because such freedom has diminished.

Practicing pop sociology, I attribute this decrease in children’s freedom to the Atlanta Child Murders, the Missing Kids on the back of Milk Boxes, Adam Walsh, and Amber Alerts, all which are making child kidnapping seem much more common than it was before or than it really is. Couple this with the decreased number of children per family, meaning children are less disposable than they once were.

Milk Carton Kids
Milk Carton Kids

Today’s kids sit in the back seat, have a much diminished range, are more likely to be driven by parent or school bus to their school.

Drivers from other countries in the US are often derided as poor quality. However, keep in mind, they grew up seldom riding in a car at all if ever, and thus never learned the tacit rules of driving that many Americans are accustomed to. Perhaps the driving tests in the US are insufficiently stringent, but there are many things one can learn about driving just be riding in the front seat of a car, which immigrants, and today’s kids, fail to experience.

VW Drivers Wanted
VW Drivers Wanted

The net is that when you go through life as a passenger rather than a driver, your motivation for driving is lower, since you are not modeling driving yourself as you would watching through the front windshield, and your quality of driving is lower since you lack experience. These two factors presumably feed on each other, as people like doing what they are good at. I posit this as one of a number of factors that has led to a significant decline per capita travel.

The End of Traffic and the Future of Access: A Roadmap to the New Transport Landscape. By David M. Levinson and Kevin J. Krizek.
The End of Traffic and the Future of Access: A Roadmap to the New Transport Landscape. By David M. Levinson and Kevin J. Krizek.

Altruism and discrimination in traffic

| David Levinson

 Modeled Behavior reports on: Altruism and discrimination in traffic:

“A new working paper by Redzo Mujcic and Paul Frijters uses the question of ‘Who stops for whom in traffic?’ to shed light on several important and interesting issues related to when, why, and for whom we exhibit altruism. Here is how they summarize their results:

We study social preferences in the form of altruism using data on 959 interactions between random commuters at selected traffic intersections in the city of Brisbane, Australia. By observing real decisions of individual commuters on whether to stop (give way) for others, we find evidence of (i) gender discrimination by both men and women, with women discriminating relatively more against the same sex than men, and men discriminating in favour of the opposite sex more than women; (ii) status-seeking and envy, with individuals who drive a more luxury motor vehicle having a 0.18 lower probability of receiving a kind  treatment from others of low status, however this result improves when the decision maker is  also of high status; (iii) strong peer effects, with those commuters accompanied by other  passengers being 25 percent more likely to sacrifice for others; and (iv) an age effect, with  mature-aged people eliciting a higher degree of altruism.”

“Street code”

| David Levinson

streetcode-thumb-400x517-73943

I don’t know why I didn’t see this earlier, World Streets proposes a Street Code

The idea is works is that legal responsibility for any accident on street, sidewalk or public space, is automatically assigned to the heavier faster vehicle. This means that the driver who hits a cyclist has to prove his innocence, as opposed to today where the cyclist must prove the driver’s guilt (not always very easy to do).

I suppose there is a conflict if the heavier vehicle is not necessarily faster, or if you get the irrational (drunk) pedestrian or cyclist, but it seems a good heuristic that will give those who impose the greatest unsafety externality the incentive to yield.
Note that all vehicles are expected to yield to trains, because trains can’t brake quickly (and they were there before cars in general), despite the fact that trains were heavier.

147 Vehicles and Pedestrians in 4:18

| David Levinson

Franklin5waySignal.m4v

My favorite five-way intersection (Franklin Avenue/East River Road/27th) has now been signalized for over a month. The video was taken on Oct 11 in the late afternoon (I apologize for the poor angle, but I wanted the same position as before as much as possible, unfortunately the sun did not cooperate (or alternatively the clouds did not obscure the sun), also I reduced the resolution for the Web). Other differences to note are that school is now in session.

The intersection was roughly at capacity (as can be seen), in that most conflicting movements were fully served with approaching cars, though I suspect throughput could be a bit higher.

We observe a throughput of about 1948 vehicles per hour (based on my estimate of 147 vehicles and pedestrians and bicyclists in 4:18), which compares favorable with the more chaotic 5-way stop during reconstruction which served about 1600. There seems a long period of lost time that could perhaps be used to improve capacity/lower delay.

The main difference is the extra capacity due to more systematic parallel movements (yielding more than one critical point). Notice the pedestrians just past the 4 minute mark are still quite confused as to whether to go or not.

As a user, the pedestrian timing is still terrible, and I just go whether or not I have the signal, so long as I am unlikely to be flattened like a pancake by oncoming cars.

Smarter Than You Think – Google Cars Drive Themselves, in Traffic

| David Levinson

From NY Times Smarter Than You Think – Google Cars Drive Themselves, in Traffic : “”

Google has adopted the Stanford and Carnegie Mellon autonomous car programs it seems. Glad there is some real money behind this stuff in the US, given the financial status of US carmakers.
Also see Google blogs: What we’re driving at
and TechCruch: World-Changing Awesome Aside, How Will The Self-Driving Google Car Make Money?

85 vehicles and pedestrians in 3:11

| David Levinson

This movie was taken by me, with my iPhone, on the way home from work on August 19, 2010 at 5:22 pm. The five-way stop controlled intersection (Franklin Ave/ East River Road / 27th Ave) seems to have a maximum throughput just over 1600 vehicles per hour. Most of the movements are saturated during the peak. This intersection has been blogged about before.

The downside for a stop controlled intersection is that the allocation of time across legs is “unfair”, i.e. drivers are supposed to take turns (yield to the right). Thus a leg which is just saturated will get just as much access to the critical points of the intersection as a leg that is supersaturated, resulting in much higher delays on the supersaturated movements. I did not measure delay, but it is longer on this day for travelers moving WB on Franklin Ave.

There are several other points to note.

(1) Drivers do not all know the “yield to the right” rule.

(2) This results in “negotiations” between drivers about who should go. Less aggressive drivers clearly lose, but eventually go.

(3) This generally increases throughput compared to obeying rules (do not start until the intersection is cleared is violated, to the benefit of throughput).

(4) The intersection is confusing but safe. Any crashes during peak times would be very low speed.

(5) It is more confusing because of the construction.

(6) The intersection was configured with operating signals in September 2010.