Working on the Hot Seat
Powers, Mike, Human Ecology Forum
The stress of traffic congestion, tight schedules, and dealing with passengers causes high rates of stress-related health problems in bus drivers. Professor Gary Evans and his colleagues are finding that new ideas in bus route design may do a great deal to alleviate their stress.
How does this sound for a job description? You must adhere to an extremely rigid schedule even though factors beyond your control will often prevent you from maintaining the schedule. You're responsible for the safety of large numbers of people and must routinely take quick action to avoid situations that threaten their safety as well as your own. And you have to sit in one place for long periods of time and deal with people who complain about your job performance. Oh, and one last thing - you're supposed to be cheerful.
Welcome to the world of the urban bus driver, or as Gary Evans calls it in the title of a recent paper published in the Journal of Accident Analysis and Prevention, "Working on the Hot Seat."
Evans, a professor in the Department of Design and Environmental Analysis, says that being a bus driver in a city is characterized by a combination of high workload demands and low levels of control. This combination has been found to be strongly associated with cardiovascular disease in a number of occupations. It also has been shown to cause increased psychophysiological stress in laboratory studies.
"Bus drivers die at a younger age from coronary heart disease, retire earlier with physical disabilities, and are absent from work with gastrointestinal, musculoskeletal, and nervous disorders far more often than workers in other occupations," he says. "The stress of traffic congestion, dealing with passengers, and trying to stay on schedule takes a severe toll on their health."
Evans and his colleague Gunn Johansson, a professor of psychology at the University of Stockholm in Sweden, didn't set out to study bus drivers. They're interested in how people react to stress. In bus drivers they found a sample that had several unique characteristics.
"Stress can come from both the social environment and the physical environment," Evans points out. "It also involves individual characteristics. Bus drivers are a group of people for whom all these factors play a role."
Evans reports that more than twenty epidemiological studies have been conducted on bus drivers. A study in the Netherlands showed that city bus drivers retired at an average age of 48, five years earlier than other civil employees. Of the 1,672 drivers who retired in the period studied, a third retired because of psychiatric problems and a third for musculoskeletal disorders. More than a third were partially or totally disabled. Only 12 percent of the drivers who retired had worked until their designated retirement age.
In a study of black and white male bus drivers in San Francisco, the drivers were found to have higher incidence of hypertension than several control groups made up of men of similar ages, races, and employment status who lived in the same county. The degree of hypertension was found to increase with age and years of service.
Evans and Johansson have conducted studies of bus drivers that examine biochemical indicators for stress. Their analyses of urine samples have shown elevated levels of hormones that are related to psychological stress.
"One way to measure stress is to look at certain neuroendocrine hormones," Evans says. "The most common are adrenaline, noradrenaline, and cortisol. These can be measured in the blood, urine, and saliva. I look at them in urine most of the time because urine is a better marker for the effects of chronic stress.
"We found that the bus drivers in our studies experienced marked increases in the levels of these hormones, particularly during peak traffic hours. They also reported higher levels of stress and were observed to manifest nonverbal indices of tension and nervousness. …