Human Factors

(Flickr image from Drocksays under a Creative Commons license.)

This piece grew from our meeting with the Bartlesville Pedalers last week.

As most of you know, I work in aviation. Safety is a major part of my recurring training, and one of the longest courses is called Human Factors. There is often a chain of events that leads up to crashes and incidents. Human Factor training is meant to make us recognize possible safety problems and prevent them. Between 80 and 90 percent of all crashes are due to human factors. The rest are mainly attributed to weather and equipment failure.

I've been thinking about trying to apply some of this to bicycle crashes, particularly ones involving bicyclists and motor vehicles because they're the main cause of fatalities. Granted, about 80 percent of all cyclist injuries are due to simple falls, and they're certainly deserving of study too. Information on these types of injuries is harder to obtain, however, because there's no standardized reporting system. Crashes involving motor vehicles are recorded in the Federal Accident Report System (FARS). While it's not perfect, it's a good place to start.

The following list is from our corporate training material and it's called The Dirty Dozen:

1. Complacency
2. Distraction
3. Pressure
4. Fatigue
5. Stress
6. Lack of (job) knowledge
7. Lack of teamwork
8. Lack of resources
9. Lack of communication
10. Lack of assertiveness
11. Lack of awareness
12. Norms

Most crashes can be traced to one of these factors, though in reality there's almost always some overlap. For our purposes, I've drawn up a similar list using bicycling crashes as the focus.

Complacency
Bikelanes: Cars never cross to the right of the magic paint stripe and bikes never cross to the left of it.

Distraction
For motorists, eating and cellular phones. For cyclists, other cyclists or pedestrians.

Pressure
I have to get to work on time!

Fatigue
Effects similar to alcohol, leading to poor reaction times and lapses in judgement.

Stress
For example, while driving home from work, I bumped into two cars when Mary was 9 months pregnant. Saying that my mind was elsewhere is a vast understatement.

Lack of knowledge
I didn't know the road, but went downhill at high speed only to discover that the pavement ended.
Improperly installed part - stem far too high, for instance.

Lack of teamwork
Boring into the wind with a wheelsucker leads to fatique and stress. (See how they overlap?)

Lack of resources
Three flats but only two spare tubes.

Lack of communication
Yell, "Stopping!" Rider runs into your back wheel anyway.

Lack of assertiveness
Newbie doesn't question the route selection or illegal operation of more experienced group leaders.

Lack of awareness
I swear I never saw him, Officer!

Norms
We always do it this way.



Here's a difficult scenario, one that almost seems to defy conventional solutions.

On a local weekend ride, there's a state highway with a long curving climb to the right that strings out the group. Part way up the hill, they want to turn left onto a two-lane county road. The highway has three lanes, 2 ascending and one descending. It has a 65mph speed limit, and there's a guardrail on the right hand side that prevents a pedestrian-style left turn. The curve limits motorist's sight lines.

Recently, two cyclists were struck by a car as they attempted this left turn. The ride leader checked over his shoulder, them moved into the left lane. The rider behind him simply followed. An overtaking car hit both of them. Fortunately, neither of them were killed though the following rider was severely injured.

Now, looking at the list above, what factors may have contributed to this crash? (Note: I use the word 'crash' rather than 'accident' because the latter implies that it was unavoidable, and as most of us realize, crashes can usually be prevented.) The obvious ones are: pressure, fatigue, and stress. We're always going to feel these while climbing a hill on a group ride. Pressure and stress come from the knowledge that we're going very slowly while overtaking traffic is travelling very fast on a relatively narrow road. We know that a momentarily distracted driver can become a very large problem in just seconds. Throw in the physical effort of climbing a hill, and the desire to get out of fast motor vehicle traffic, and you have compound human factors contributing to the crash. But I think there's one I initially overlooked, and I'll return to that thought in a moment.

Brian and I were presented with this scenario at the Bartlesville Pedalers meeting on Monday. It's a real poser. My first thought was to do a pedestrian-style left turn. That is, move off the roadway on the right and stop. Wait for a break in traffic, and then cross over to the county road. But the guardrail placement prevents that maneuver. There's no space to get off the road.

Since I normally ride solo and very seldom join group rides, this wouldn't be a big problem. I'd just try to time my movements across the lanes, signaling my intentions well in advance. Heavy traffic might make this difficult, but even then, there are significant gaps.

Imagine the confusing scene before an overtaking motorist when there's a group on this road, however. There are 'clumps' of riders strung out in the right hand lane, and perhaps several have moved left in order to make that turn. The motorist is distracted by trying to pay attention to all the various movements, and he dithers before deciding to slow down. He's not accustomed to sharing the road with slow-moving cyclists. His momentary confusion slows his reaction time. Just as magicians use misdirection to pull off a trick, he's looking in the wrong place at the wrong time, and high speed relative to the cyclists only aggravates the problem.

Teamwork is what I initially overlooked. Consider this - a fragmented group climbing a hill offers motorists a series of problems to solve in rapid succession as he overtakes each individual or small group.

My proposed solution is to keep the group together. Don't allow the group to string out. Before reaching the bottom of the hill, move the slowest climbers to the front and everyone climbs at their pace. When it's time to initiate the left turn, the ride leaders at the back of the pack move to the left first, communicating their movement to the riders ahead.

Now, you can see the obvious difficulties in doing this. It requires teamwork, good communication, cooperation, and planning. This maneuver - putting the slowest rider to the front in order to remain a cohesive group - must be clearly communicated to the entire group before the ride starts and it must be executed BEFORE they start the climb. The goal is to provide safety in numbers for the riders, and provide unambiguous communication of their intentions to any motorist they encounter on the hill. A large, cohesive group is easier for a motorist to observe and avoid rather than scattered individuals and 'clumps.'

As for studying human factors in bicycle/motor vehicle crashes, I'm going to collect news stories and try to tabulate them in some way. Obviously, I don't have access to the detailed information found in the FARs, so this can hardly be considered scientific. I've wondered, though, if it's possible to get a large sample of those reports through a Freedom of Information Act (FOIA) request. If any of you have had some experience with this, please let me know.

A brief diversion...

(Photo Link)

One of my co-workers crashed on the MS150 ride this weekend when his front wheel dropped into an expansion joint on the road. His helmet shattered and he broke two ribs. An ambulance arrived to transport him to the local hospital, and while they loaded him aboard, another cyclist crashed in the same spot.

This type of fall, where the front wheel gets trapped or suddenly thrown to one side, is commonly called a diversion fall. Anything that causes the front tire to lose adhesion can bring about an unexpected, very sudden crash. The contact patch under the tire is roughly the size of a thumb print. It does about 2/3 of the braking and provides all directional control.

Besides the obvious hazards of wheel-trapping drain grates, we have to be wary of railroad tracks, streetcar tracks, pavement cracks or expansion joints parallel to our direction of travel, patches of oil or diesel fuel, sand, gravel, leaves, and manhole covers. Rain increases the hazard because it reduces traction.

I wish I could tell you there's a technique to recover from an incipient diversion fall, but the best recommendation is to be attentive and avoid getting your wheel trapped in the first place. Yeah, that sounds good. It's not a universal solution, and even for those of us commuting on the same roads day after day, it doesn't always work. And when we're riding a new, strange road, paying attention is even more critical.

It's certainly true we can be too complacent. I'm thinking about a near-tumble a few months ago. In the pre-dawn darkness, I was maneuvering left across two lanes of traffic onto a dedicated left turn lane. I'd done this hundreds of times, but that morning as I went from the left-most travel lane into the dedicated turn lane, my front tire dropped into a deep expansion joint. It stuck for only an instant, but in that instant my heart rate went way, way up! I was very fortunate not to crash as there was motor vehicle traffic to my right. I stopped under a street light to inspect the sidewalls for damage because a crevice or expansion joint can cut the side of the tire.

But as I said, I'd been through there hundreds of times without any problems. I assumed that the road surface was the same every day and that I rode on the same space every day. Big mistake.

Likewise, when I turn south onto Mingo Road from 76^th Street, I've learned to expect something unusual. There's a streetlight on the north side of 76^th, but it doesn't illuminate the downhill turn onto Mingo very well. Sometimes there's debris strewn across the lane and I can't see it. I hear it crunching under my wheels. The best way to avoid a fall there is to be sure I'm not turning when I hit a patch of sand or gravel. Turn, straighten up across the sand, then turn again.

So let's be careful out there. Pay attention to the road surface in front of you, especially if you're riding somewhere new and different, and don't fall into the trap of complacency on the routes you know like your own living room.