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Objective: To estimate the impact of employee alcohol and drug use on crashes in the transit industry from 1995-2000., Design: Secondary analysis of federally mandated post crash and random alcohol and drug testing results., Setting: The US transit industry., Subjects: Transit industry employees., Main Outcome Measures: Relative risk (RR), population attributable risk (PAR), and population attributable risk percentage (PAR%)., Results: For alcohol testing, the estimated PAR% ranged from 0.02% (1999) to 0.03% (1995). For drug testing, the estimated PAR% ranged from 0.38% (1998) to 0.67% (1997). Based on these calculations, the estimated number of crashes per 1000 crashes attributable to alcohol was less than one during 1995-2000, and the number attributable to drugs ranged from about four to about six. The number of crashes attributable to either alcohol or drugs did not vary greatly from 1995-2000. Estimated rates of crashes attributable to alcohol or drugs were substantially lower in 1995, the first year of testing, than had been projected based on previous estimates, and did not show substantial change from 1995-2000., Conclusions: Approaches to transit safety based on reducing employee use of alcohol and other drugs have modest potential for reducing number of fatalities, injuries, and crashes.

Objective: A growing body of literature is documenting the health effects of racial discrimination. The authors investigated the association between racial discrimination and alcohol-related behavior in a sample of urban transit operators., Methods: Using data from a 1993-1995 cross-sectional study of transit operators in San Francisco, California, the authors analyzed responses to two sets of questions about racial discrimination; the first set focused on reaction to unfair treatment and the second on arenas, or domains, of discrimination. Alcohol-related variables were: number of drinks per month, heavy drinking, alcohol dependence, and negative consequences of alcohol consumption., Results: Operators who reported five or more domains of discrimination drank an average of 13.4 more drinks per month than those who reported no domains of discrimination (P = 0.01). Similarly, they were more likely to be heavy drinkers (adjusted odds ratio [OR] = 2.16; 95% confidence interval [CI] 1.14, 4.09) and dependent on alcohol (adjusted OR = 2.02; 95% CI 1.08, 3.79) than operators who reported no domains of discrimination. The number of domains in which operators reported having experienced discrimination was not related to sex, age, household income, job seniority, or marital status, but varied significantly by educational level and race/ethnicity., Conclusions: Data from a sample of urban transit operators showed an association between the number of domains of discrimination and some alcohol-related outcomes, but not others.

Study Design: Five-year prospective cohort study of 1449 transit operators., Objectives: To investigate psychosocial job factors as predictors of work-related spinal injuries, controlling for current and past physical workload., Summary of Background Data: The association between psychosocial job factors and spinal disorders may be confounded by physical workload. A 1991 prospective study of Boeing workers found psychosocial but not physical factors to be associated with spinal injuries. However, data on physical workload were limited. Recent cross-sectional studies of transit drivers showed both physical and psychosocial factors to be independently associated with back and neck pain. This study was designed to test these findings prospectively., Methods: Spinal injuries were ascertained from workers' compensation records, employment history from company records, and psychosocial factors from questionnaires. Logistic regression models adjusted for age, gender, height, weight, vehicle type, and current and past physical workload., Results: During follow-up, 320 drivers reported a first spinal injury. Spinal injury was predicted by psychological job demands (odds ratio [OR], 1.50; 95% confidence interval [CI], 1.33-1.95); job dissatisfaction (OR, 1.56; 95% CI, 1.09-2.23); and the frequency of job problems (OR, 1.52; 95% CI, 1.02-2.26). Marginally significant associations were found for low supervisor support (OR, 1.30; 95% CI, 0.99-1.72) and female gender (OR, 1.49; 95% CI, 0.95-2.32). Compared with full-time work, part-time work was associated with a 2.7-fold reduced risk for spinal injury (OR, 0.37; 95% CI, 0.15-0.93). Cable car crews performing the heaviest physical labor had a threefold increased risk of spinal injury compared with bus drivers (OR, 3.04; 95% CI, 1.85-5.00)., Conclusions: Physical workload and psychosocial job factors both independently predict spinal injury in transit vehicle operators.

Eighty-one observational work analyses were conducted to measure stressors independently of worker appraisal in the San Francisco transit system. On the basis of action regulation theory, stress factors were defined as hindrances for task performance due to poor work organization or technological design. Stressors included (a) work barriers, defined as obstacles that cause extra work or unsafe behavior; (b) time pressure; (c) monotonous conditions; and (d) time binding, defined as control over timing. Reliability, measured as interrater agreement, ranged between 80 and 97%, with kappas of .46-.70. Validity analyses were done with 71 transit operators who participated in the observations and 177 operators who were assigned mean line-specific observational stressor measures. High odds ratios (ORs) were found for barriers and psychosomatic complaints (OR = 3.8, p = .00), time pressure and relaxation time needed after work (OR = 3.1, p = .05), and barriers and smoking to cope (OR = 3.8, p = .02). Using observational data in conjunction with self-report data can reduce confounding and improve interpretability of stress and health studies.

Objectives: This cross-sectional study examined associations between psychosocial job factors and the prevalence of nondisabling back and neck pain in professional drivers after physical work load was taken into account., Methods: A total of 1449 transit vehicle operators completed a medical examination and a questionnaire yielding information on demographic and anthropometric variables, health status, and physical and psychosocial job factors. Company records were used to supplement information on employment history. Physical work load was measured in life-time years and current weekly hours of professional driving. The relation of psychosocial factors with back or neck pain was analyzed by logistic regression models adjusted for past and current physical work load, vehicle type, age, gender, body height, and weight., Results: The main result of this study was that both physical work load and psychosocial factors were simultaneously and independently associated with back or neck pain. Psychosocial factors associated with back or neck pain included extended uninterrupted driving driving periods, frequency of job problems, high psychosocial demands, high job dissatisfaction, and low supervisory support. An analysis of specific job problems is provided which may be useful in setting priorities for research and intervention efforts in this high risk occupation., Conclusion: The results provide support for the role of psychosocial job characteristics in the etiology of back or neck pain in occupational settings.

Background: The influence of occupation and the worksite has emerged as an important area of study in research on alcohol consumption. Occupational and nonoccupational factors were studied in relation to alcohol consumption using data from a 1983-1985 cross-sectional study of transit operators., Methods: A total of 1.853 operators underwent a medical examination for driver's license renewal (including information on age, ethnicity, gender, education). Of these operators, 1,448 completed a questionnaire about occupational (e.g., time of shift, job stressors) and nonoccupational (e.g., personality, life stressors) factors. From either the medical examination or the questionnaire, weekly alcohol consumption was available for 1,820 operators. Variables related to alcohol consumption in previous studies, or theoretically linked to consumption, were analyzed in relation to heavy ( > or = 15 drinks/week) and average weekly consumption., Results: Heavy and average consumption were both related to several nonoccupational variables, including demographic (age, ethnicity, gender, marital status), personality (depression, anger expression), and life stress variables (i.e., life events). Heavy and average consumption were also related to several occupational variables, including job history (number of years driving, specific worksite) and job stressors. Neither measure was related to subjective job content (job demand, decision latitude)., Conclusions: Variability in consumption by demographic factors among this population reflects that seen in society as a whole. However, occupational factors may influence consumption, since consumption was strongly related to (a) specific worksite and time of shift and (b) reported job stressors. Clarifying the exact influence of occupational and worksite factors on alcohol consumption will depend on the convergence of findings from different research designs (e.g., cross-sectional, longitudinal, ethnographic).

This study reports an analysis of collisions occurring between public transit vehicles operated by the San Francisco Municipal Railway System (Muni), the public transit agency for the City of San Francisco, and nontransit vehicles. The analysis, focusing on weekday collisions during 1987, demonstrated a strong association between hourly transit collisions rates and hourly traffic volume. The collision rate varied from 0.01 per 1,000 Muni vehicle-hours of operation during the interval 5 A.M. to 6 A.M., a time of very low traffic volume, to 0.93 (approximately 1 collision per 1,000 Muni vehicle-hours of operation) during the interval 5 P.M. to 6 P.M., a time of very high traffic volume. Using a power function to predict either the total number of collisions, or the rate of collisions per 1,000 Muni vehicle-hours, almost 90% of total variation was accounted for by traffic volume. A very similar pattern was found for collisions judged either avoidable or unavoidable. A peak in the collision rate between 2 A.M. and 3 A.M. could not be accounted for by traffic volume alone. That peak occurred in the one-hour interval following the 2 A.M. closing of bars in San Francisco, and was composed entirely of a sharp increase in unavoidable collisions. Increasing traffic volume appeared to operate through two mechanisms: (i) an increase in the number of opportunities for a collision, defined as a quantity proportional to the product of the number of Muni and non-Muni vehicles; (ii) an increase in the probability of a collision occurring between any given pair of vehicles.

This paper reports the results of a cross-sectional study conducted to evaluate the prevalence of hypertension in 1500 black and white male bus drivers from a large urban transit system in the US. Data for this study were compiled from the files of an occupational health clinic which conducts biennial medical examinations for drivers' license renewal. To test whether prevalence of hypertension was higher among bus drivers than among employed individuals in general, drivers were compared to three groups: individuals from both a national and local health survey and individuals undergoing baseline health examinations prior to employment as bus drivers. After adjustment for age and race, hypertension rates for bus drivers were significantly greater than rates for each of the three comparison groups. These findings support previous results from international studies of bus drivers suggesting that exposure to the occupation of driving a bus may carry increased health risk. This research has expanded into an on-going study which has the goals of clarifying the extent of hypertension in bus drivers and identifying specific behavioural and occupational factors that may be responsible for increased risk of cardiovascular disease.

In an extensive search of available literature, 22 epidemiological studies that have examined health risks of bus drivers were identified. These studies focus on three main disease categories: (1) cardiovascular disease, including hypertension, (2) gastrointestinal illnesses, including peptic ulcer and digestive problems, and (3) musculoskeletal problems including back and neck pain. The studies consistently report that bus drivers have higher raes of mortality, morbidity, and absence due to illness when compared to employees from a wide range of other occupational groups. Increased disease rates have been found for drivers regardless of the use of different research methodologies, measurement techniques and comparison groups. When evaluating the impact of bias on the estimates of risk, it appears likely that findings are conservative: strong systematic selective factors have probably favoured the elimination of those in poorer health both at the time of entry into and exit from the job of bus driving and other sources of bias have most likely caused underestimations of risk. Nevertheless, there remain questions that need careful assessment before firm conclusions can be made about whether increased disease rates result from driving a bus. Such questions, coupled with the consistent findings of heightened risk of disease, make urban bus drivers an appropriate and promising occupational group in which to study further the potential adverse effects of the work environment on employee health.