Category Archives: transportation

11 feet 8 inches

A train trestle in Durham, NC has a clearance of 11’8″.

The typical height of a large rental truck ranges from 11’6″ (don’t bounce!) to 13’6″.

How often do you think about clearance when driving? Do you think you could adjust to thinking about it 100% of the time in your rental truck?

I’ve seen parking garages that have a hanging bar well before the low ceiling to notify drivers that they are not going to make it. The bar, on chains, will bang the front of the truck but not peel the top off as the bridge does. The trucks in this video are going to quickly, this warning would have to come well before they crossed the intersection. This solution probably has problems too. I’m sure there would be drivers who were planning to turn before the bridge that get mad that a bar hit their truck. Also, getting someone to pay for and maintain the bar might be difficult as the trestle owners want to blame the drivers (and so do other drivers, if you read the comments on the video.)

More video and information is availible at Videos copyright Jürgen Henn –

Redesigning Toyota’s Keyless Ignition System

The LA Times reporters Ken Bensinger and Ralph Vartabedian recently wrote a story about keyless ignition systems and the associated HF issues (we blogged about it here).  In a follow-up story, they report that Toyota is considering redesigning the system so that instead of requiring a single 3-second press to shut off the engine, it now requires 3 consecutive presses.  This is to address the fact that drivers, in emergency situations, don’t readily know how to stop the car:

Amid its widening recall crisis, Toyota Motor Corp. said it had moved closer to adopting changes to its push-button ignition system to give drivers an added margin of safety if their vehicles accelerate out of control.

Executives at the company’s headquarters in Japan are considering redesigning the keyless ignition system, known as Smart Key, to allow drivers to shut off the engine by tapping the button three times in a row, company spokesman Brian Lyons said.

But it might be a hasty fix since very little research has gone into how users expect it to operate:

Paul Green, a human factors expert at the University of Michigan Transportation Research Institute, said Toyota and other carmakers have designed push-button start systems with very little research about how consumers naturally expect such systems to operate.  Green said that if Toyota now rushes a redesign into production without any new research, “it is really risky.”

I was quoted too:

According to Richard Pak, a professor of psychology at Clemson University who studies human interaction with technology, the safest kind of ignition switch is one that works in an intuitive manner. That’s because in a panic situation, humans “revert to [very well] learned behavior.”

“When you’re out of control at 80 miles per hour, you’re not going to remember complicated things,” Pak said.

Keyless Ignition in Emergencies: Do you know what to do?

This story in the LA Times illustrates several important HF/usability issues.  First, the  importance of knowing what the user knows before introducing new, seemingly “simple” technology, or changing the way they currently do things (in this case, what people know about ignition systems and how they start their cars).  Second, like the story about the alarms, it also clearly illustrates that using things under normal circumstances is different for people under stress.

The sleek Infiniti G37 Cindy Marsh bought last August was the car of her dreams, equipped with the latest keyless electronics technology that allows her to start the engine with the touch of a button.

Button in the G37

But right away, the system gave her trouble. To get the engine started, she would sometimes have to tap the power button repeatedly. Sometimes it wouldn’t start unless she opened and closed the car doors, Marsh recalled.

She eventually adapted to the system’s quirks but said that even now she isn’t sure how to shut off the engine in an emergency.

In complaints to federal regulators, motorists have reported that they were unable to shut down engines during highway emergencies, including sudden acceleration events. In other cases, parked vehicles accidentally rolled away and engines were left running for hours without their owners realizing it.

And although traditional keys all work the same way and are universally understood by consumers, automakers have adopted different procedures for using the keyless ignition systems. As a result, owners may not know how to operate their own cars in an emergency, let alone a rented or borrowed car.

(Post image by

Pssssst! Free occupational safety data!

Do you love databases? Especially if you are interested in safety, there are a number of carefully archived databases of events out there. A couple of years ago, I found one of these while trying to answer the question “What kinds of human factors interventions would be most increase agricultural safety?” Six months of coding later, I had some answers and a good direction for my research program*.

The posts describing the databases I have found are long, so I will spread them out over multiple posts under the category “Databases.” Today’s database is…

The Fatality Assessment and Control Evaluation (FACE) Progam – NIOSH

This database from the National Institute of Occupational Safety and Health covers fatal accidents in a number of areas with a standard interview and evaluation for each case. These are rich descriptions with the added benefit of having an expert in that field try to assess what went wrong. Some of the areas they cover are highway work zones, agriculture, commercial fishing, commercial aviation, construction, and logging. Each case includes a summary, descriptions, pictures, analysis, and recommendations to prevent a re-occurrence. Here is an excerpt of one of their cases:


Mid-spring 2005, a 29-year-old man died when the tractor he was operating overturned upside down pinning him underneath (Photo 1). The 40-year-old tractor had a narrow (tricycle) front axle. It did not have a rollover protective structure (ROPS). A front-end loader was attached to the tractor’s frame but no counter-weights had been installed for ballast. The loader with its bucket full of rocks was raised to nearly hood height. The tractor leaned to the right as the man steered it forward at a slight upward angle on a slope. The position of the heavy load, the absence of ballast, the tractor’s configuration, the dynamics of the tractor-loader combination and its load in transport on the sloping, uneven terrain contributed to the sudden overturn of this tractor. ROPS and use of the seat belt would likely have prevented this man’s death.

Photo 1 – Tractor without ROPS at scene of overturn. Note the rocks spilled from the loader bucket and height of the loader bucket relative to the tractor’s hood.

Photo 1 – Tractor without ROPS at scene of overturn. Note the rocks spilled from the loader bucket and height of the loader bucket relative to the tractor’s hood.

RECOMMENDATIONS based on our investigation are as follows:

  • Agricultural tractors should be equipped with a rollover protective structure (ROPS) and the seat belt should be used, except with foldable or retractable ROPS in their down or retracted position.
  • ROPS should be designed and readily available for all makes and models of agricultural tractors in common use..
  • Front-end loaders should not be installed on narrow-front (“tricycle”) tractors that do not have a ROPS.
  • Operators handling heavy loads should follow manufacturer recommendations for proper equipment, set up, ballasting, and safe operating practices.

And that’s just the summary! You can look at cases by state, by cause and any number of other variables.

John presenting poster at HFES 2009

John presenting poster at HFES 2009

“Replicants are like any other machine – they’re either a benefit or a hazard. If they’re a benefit, it’s not my problem.”

brcarElectric cars are utterly silent making them hazardous when they sneak up on you at low speeds.  Nissan is thinking about having their Leaf electric car emit the whine reminiscent of the flying cars in Bladerunner.  It’s one of my favorite movies so I approve!

“We decided that if we’re going to do this, if we have to make sound, then we’re going to make it beautiful and futuristic,” Tabata said.

The company consulted Japanese composers of film scores. What Tabata and his six-member team came up with is a high- pitched sound reminiscent of the flying cars in “Blade Runner,” the 1982 film directed by Ridley Scott portraying his dystopian vision of 2019.


HF/Usability Hodgepodge

Things too small for their own post but interesting nonetheless…it’s a hodgepodge, a mélange, a potpourri!

Ford’s Use of Personas in Design

This NYT article delves into the use of personas at Ford Motor Company.  The article is written to imply that the use of personas (or archetypes as they call it) is novel.  It also delves uncomfortably and unnecessarily into Jungian psychology (psychological archetypes, eh?).

But many designers and user experience people have been using personas for quite a while.  The article does not mention Alan Cooper who was pivotal in articulating the benefits of personas in design.  From the article:

ANTONELLA is an attractive 28-year old woman who lives in Rome. Her life is focused on friends and fun, clubbing and parties.

Antonella was the guiding personality for the Ford Verve, a design study that served as the basis for the latest-generation Fiesta. A character invented by Ford designers to help them imagine cars better tailored to their intended customers, she embodies a philosophy that guides the company’s design studios these days: to design the car, first design the driver.

Personas can contain varying levels of detail but some contain the character’s motivations and attitudes  (as evidenced above).  They should contain enough detail for the designer to answer the question, “Would Antonella like this feature?”, “How would she complete this task”?

The benefit other benefit of personas is that they help focus the design team’s efforts into a single user (who represents a class of users).  More detail on personas can be found on the Wikipedia entry or even better Alan Cooper’s book.

Electric Scooters and their Warnings: A Guest Post by Kim Wolfinbarger

Electric shopping carts are common in large grocery stores. Essential for users with mobility impairments, they are also helpful for pregnant women, elderly shoppers, and other who have trouble walking long distances.

A few months ago, my grandfather overturned such a cart in a parking lot and broke his hip. Interested in what might have caused the accident, I examined a similar cart at my local store.

in-storeWhile the cart appeared stable, red-and-white signs affixed to the inside and outside of the basket read, in large letters, “IN-STORE USE ONLY.” Two others warned, “INTENDED FOR USE INDOORS ON LEVEL SURFACES ONLY!” and “DO NOT TAKE THIS CART OUTSIDE THE STORE.” An instruction manual I found online had similar statements in several places.

instructionsHere is the problem: A customer who uses the cart while shopping will surely want to use it when taking groceries to the car. My grandfather lived independently and drove himself to the store, but rheumatoid arthritis made walking difficult. Using an electric cart made it possible for him to do his own shopping. While he most likely saw the warning, he may have dismissed it as a statement written to merely to discourage lawsuits. (This is speculation–he could not converse following the accident and died a few weeks later–but it is consistent with his personality.)

Clearly the manufacturer had anticipated that people would use the carts outside and thought this behavior might be hazardous.  But did the store share this concern? Since the cashier loaded the bags into his cart following the purchase, it appears that, despite the warning, the store expected him to drive the cart to the parking lot.


The signs and repeated warning statements in the manual suggest a mismatch between the design of the product and the expected behavior of users. So how should the problem be addressed?

  • If the carts are truly not stable outdoors, stores should not allow them to be driven into the parking lot. Instead, employees should carry out groceries for all customers who use a motorized cart.
  • Offering the service is not enough; some customers, not wanting to be a bother, will refuse assistance if asked. Instead, when the cashier begins checking out a customer with an electric cart, she should immediately summon a worker to load the groceries into a push cart and take the groceries to the customer’s vehicle.
  • Manufacturers should assume that customers will take electric carts outdoors and design them accordingly. Motorized scooters intended for outdoor use are widely available.
  • If they have not already done so, shopping cart manufacturers should implement similar stability features.  As human factors engineers have said for years, a warning is no substitute for good design.
  • Good warnings tend to have a “why” that informs the user about the hazard when that hazard is not immediately obvious. If you though the reason to keep the cart indoors was because you might be hit by a car, your decision to take the cart outdoors could be different than if you knew the cart were unstable.

Kim Wolfinbarger is the recruitment coordinator and an adjunct instructor for the School of Industrial Engineering, University of Oklahoma. Her research interests include usability, product design, industrial ergonomics and design for special populations.

Emergency Checklists and Aviation

The recent water landing into the Hudson is still being investigated. This AP article focuses on whether flight attendants were trained not to open the back door of the plane during a water landing, but the most interesting bit comes at the end:

Another concern is whether the FAA and airlines need to revise emergency procedures for pilots in the event both engines fail. Those procedures usually involve a sequence of many steps called a checklist. There are different checklists depending upon the problem, but most are based on the expectation that the problem will occur while the plane is flying at a high altitude — airliners typically cruise above 20,000 feet, giving pilots time to identify and correct the problem.

Flight 1549’s first officer, Jeffrey Skiles, told a congressional panel in February that he only had time to make it part of the way through a checklist for restarting the engines when Sullenberger sent the plane into the river.

Sumwalt suggested it would be better for airlines to train pilots to remember one procedure for a low-altitude dual engine failure, rather than go through a long checklist of items while altitude rapidly diminishes.

Accidental Activation Activates Fighter Jet Escort


Apparently there is a particular communication channel airlines use when they have been hijacked. This afternoon, an American Airlines flight was escorted by fighter jets to Miami when the channel was set on a flight from Puerto Rico.

This interface error sounds expensive. Can we assume the flight crew did not know they were using this frequency?