|Year : 2019 | Volume
| Issue : 1 | Page : 48-53
A cross-sectional study of prevalence of depression, anxiety and stress among professional cab drivers in New Delhi
Akanksha Rathi1, Vikas Kumar1, Amrita Singh2, Panna Lal1
1 Department of Community Medicine, Dr. Baba Saheb Ambedkar Medical College and Hospital, New Delhi, India
2 Ministry of Health and Family Welfare, New Delhi, India
|Date of Web Publication||15-Apr-2019|
Dr. Vikas Kumar
Department of Community Medicine, Dr. Baba Saheb Ambedkar Medical College and Hospital, New Delhi
Source of Support: None, Conflict of Interest: None
Background: The profession of drivers is one of the occupational groups exposed to very poor working conditions. This study aimed to establish the prevalence of depression, anxiety and stress among cab drivers. Materials and Methods: This cross-sectional study included 134 cab drivers. Their mental health status was assessed with the help of a screening tool – Depression Anxiety Stress Scale (DASS-21). Their demographic details, working conditions, lifestyle factors and use of habit-forming substances were also assessed with the help of a semi-structured questionnaire. Results: It was revealed that all cab drivers were male and between 20 to 64 years of age. Eighty two (62%) drivers said they are sometimes irritated at work, 29 (21.5%) said they feel irritated daily and rest 23 (17.2%) said that they were never irritated at work. When screened for depression, anxiety and stress, it was found out that 81 (60.5%) were suffering from depression, 63 (47%) from anxiety and 49 (36.5%) had variable degree of stress. Conclusion: Cab drivers are at high risk of acquiring mental health diseases, yet the mental health of this large workforce is ignored.
Keywords: Cab drivers, DASS-21, mental health, occupational health, substance abuse
|How to cite this article:|
Rathi A, Kumar V, Singh A, Lal P. A cross-sectional study of prevalence of depression, anxiety and stress among professional cab drivers in New Delhi. Indian J Occup Environ Med 2019;23:48-53
|How to cite this URL:|
Rathi A, Kumar V, Singh A, Lal P. A cross-sectional study of prevalence of depression, anxiety and stress among professional cab drivers in New Delhi. Indian J Occup Environ Med [serial online] 2019 [cited 2019 Jun 17];23:48-53. Available from: http://www.ijoem.com/text.asp?2019/23/1/48/256223
| Introduction|| |
Last few years has seen many changes in terms of how a common man commutes in the populated capital city of India. Many years ago, there was a monopoly of public buses and auto rickshaws over the commute of the majority. Then came the majestic Delhi metro, having a daily ridership of over 3 million, boasting of being the most cost effective and punctual solution to travel within the city often crippled by traffic jams. Taxis have been in the business for years, but they fell within the reach of a common man since 2013, with the advent of application-based cab aggregators (ABCA) in Delhi, owing to the ease of online booking, minimum waiting time, doorstep pick up and drop, luxury, comfort and relatively cheap fares.
Cab drivers are at high risk of occupational morbidities and mortalities like cardiovascular diseases, physical assaults, musculoskeletal disorders like back pain and high stress.,,,, Drivers are in a profession that exposes them to physical illness, mental illness and addictions of habit-forming substances, specially tobacco. Their profession is also unique because they are bestowed upon responsibility of other people's lives, either the ones they are carrying in their vehicles or the ones on the road. New Delhi has 78,686 registered taxis (2013–14) and each day, 71 Indians die in road mishaps involving cars, jeeps and taxis. Many studies have reported that accidents and their severity are associated with age, sleepiness, drug use and smoking.,,,
In India, the taxi driver's mental health, which is a reflection of that of general population, is poor. The National Mental Health Survey (NMHS) estimated that about 150 million Indians need care for mental disorders, and about 10% suffer from common mental disorders (CMD) such as depression, anxiety, emotional stress and suicide risk, as well as alcohol and drug use. However, relatively few studies have used standardised tools to assess the burden of CMD in the population. Such studies are literally inexistent in context of occupational groups like taxi drivers in India. A study done on truck drivers reported that 30% of the truck drivers were having mental health problems and were in need of routine screening for severity of symptoms.
The prevalence of tobacco use is also reported to be higher in drivers, factory workers, labourers and police personnel due to their widespread misconception that tobacco consumption will help them to keep alert during working hours. A study in Iran reported the prevalence of drug use among drivers who had the history of car accident >50%. It is difficult to elicit history of illicit substance use among drivers, and smoking may be considered a proxy factor in that case.
Despite the significant stress that drivers face on a daily basis, no study in India has explored the prevalence of depression, anxiety and stress among drivers. The literature from other parts of the world is also sparse. Along with finding out the mental health status of drivers, the authors also intend to find out the working conditions, prevalence of musculoskeletal disease, health-seeking behaviour and use of habit-forming substances among them.
| Materials and Methods|| |
This study is a descriptive, cross-sectional research conducted on cab drivers driving in northern and western districts of Delhi, in the period of November 2017 to January 2018. A convenience sampling method was adopted for selecting 134 drivers that have been included in the study. The inclusion criteria were as follows:
- Drivers driving for >1 month
- Drivers not previously diagnosed with a mental health illness
- Drivers willing to participate in the study
The various tools used in the study were:
- A pre-tested, semi-structured questionnaire was used to find out the demographic details, working conditions, lifestyle factors and use of habit-forming substances.
- A validated Depression Anxiety Stress Scale (DASS-21) translated in the local language (Hindi) was used to know the levels of depression, anxiety and stress among the drivers. DASS-21 is just a screening tool and is used to screen patients suffering from depression, anxiety and stress in the community. The original 42-item DASS of Lovibond was modified into a shorter 21-item version. Several studies are published on its reliability and validity worldwide, all showing the DASS-21 is a well-established instrument to measure symptoms of depression, anxiety and stress in both clinical and non-clinical samples of adults (Cronbach's alpha scores of >0.7).,,,
This instrument comprises three sub-scales: (a) the depression sub-scale which measures hopelessness, low self-esteem and low positive affect; (b) the anxiety scale which measures autonomic arousal, musculoskeletal symptoms, situational anxiety and subjective experience of anxious arousal; and (c) the stress scale which measures tension, agitation and negative affect.
A convenience sample of 134 was taken for the study. A cab was booked by the investigator from north and west districts of Delhi and it was taken to the desired destination. After taking the informed consent of cab drivers, they were interviewed with the help of questionnaire at the end of the trip.
The data were analysed through descriptive statistics, Chi-square test, Fisher's exact test and linear regression using the SPSS software. In the study, a value of P < 0.05 was considered statistically significant.
This research project was approved by the Ethics Committee of Dr BSA Medical College and written informed consent was obtained from all participants. Study subjects suspected of having depression, anxiety or stress were advised to consult a specialist/psychiatrist.
| Results of the Study|| |
Sociodemographic profile of cab drivers
It was revealed that all cab drivers were male, between 20 to 64 years of age, with an average age of 32.51 ± 7.92 years, majority of them were married (112, 83.5%), migrant (86, 64.2%) and owner of the vehicle (95, 70.2%) [Table 1].
Occupational details of cab drivers
The average kilometres (km) driven per day were reported to be 222.5 ± 54.91 km and the average duration of working hours was 12 ± 2.64 h. A large number of drivers (111, 83%) did not report being subjected to or being involved in any road rage incident in the last 1 year. One half of the drivers (66, 49.5%) were reportedly booked for a traffic law violation and almost one-fourth (36, 27%) have been involved in accidents in the last 1 year. When asked about the frequency of being irritated during driving, 82 (62%) said they are sometimes irritated, 29 (21.5%) said they feel irritated daily and rest (23, 17.2%) said that they were never irritated at work. The most common causes of irritation were (in decreasing order); rude/demanding behaviour of passengers, traffic congestion, not getting enough booking, personal issues like hunger, lack of sleep, tiredness and less time for family and narrow roads or difficult to reach locations [Table 2]. The factors significantly associated with irritation of drivers were long hours of working (P value < 0.001), not taking a day off during the week (P value = 0.02) and presence of a self-reported medical condition (P value = 0.04).
Lifestyle behaviours of cab drivers
Majority (90, 67.2%) of drivers were sleeping for 5–7 h in a day, few (40, 28.2%) were sleeping for 8 h and a fewer (4, 3%) for <5 h, with an average of 6.7 ± 1.2 h of sleep during the day. Sixty (45%) drivers said they were having their meals on time, 57 (42.5%) never consumed junk food in place of a major meal and only 22 (16.4%) said they exercised at least on few days during a week [Table 3]. The risk of having junk food increased with younger age and unmarried status (P value <0.001).
Usage of habit-forming substances among cab drivers
Forty four (32.8%) drivers reported smoking tobacco, 37 (27.6%) said they used chewable tobacco and 42 (31.3%) consumed alcohol at least 2 days in a week [Table 4]. The average pack years were 4.59 and the average expenditure on smoking was 18 INR.
Self-reported medical conditions among cab drivers
Thirty four (25.3%) drivers reported suffering from gastrointestinal (GI) problems like acidity and indigestion, 52 (38.8%) reported to be suffering from musculoskeletal morbidity like back pain and knee pain, 2 (1.5%) had diabetes and 3 (2.3%) had hypertension.
Mental health status of cab drivers
When screened for depression, anxiety and stress, it was found out that 81 (60.5%) were suffering from some degree of depression, 63 (47%) had some degree of anxiety and 49 (36.5%) had variable degree of stress [Table 5]. The significant risk factors leading to stress were lack of sleep (P value = 0.009) and being irritated (P value = 0.004). Duration of sleep of <8 h was also significantly associated with an unfavourable score on the DASS-21 scale (suggesting depression, anxiety or stress) (P value = 0.02).
|Table 5: Prevalence of depression, anxiety and stress among taxi drivers|
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Healthcare seeking and access
Ninety five (70.89%) of the drivers did not have a health check up in the last 1 year. None of the drivers reported being provided healthcare insurance by the hiring companies. They were not provided with a yearly screening or any kind of health consultations.
| Discussion|| |
Cab drivers are a group susceptible to a host of physical and mental diseases. Their working conditions and lifestyle are health deteriorating. Their work schedule is rarely fixed, and they stretch long hours to make their ends meet. They neglect meals and eat whatever is cheap and available on the road. They have no time to sleep, rest aside exercise and a very few think about their health and fitness.
Their poor physical state deteriorates their mental state. Lack of sleep leads to sleepiness during daytime and impairs psychomotor skills, cognitive functions and memory and causes mood disorders. Disturbances of the circadian rhythm of sleep and wakefulness are often associated with depression, owing to the disturbed serotonergic transmission. Other factors that illicit emotional reactions in drivers is the stressful nature of work – tight timelines, congested roads, rude behaviour of customers and other drivers, frequent road rage incidents, direct relationship of hours of work and incentives and not enough time for relaxation and recreation.
This study aims to highlight the poor mental health status of cab drivers, along with their working conditions and lifestyle behaviours. The current study revealed that all drivers were males and majority were migrants. The findings are congruent with other studies.,, The current study reported that working conditions of drivers are not favourable to health as they are not getting enough sleep, have to drive for long hours and are working for 6 or even 7 days a week. Studies have suggested that taxi drivers are commonly exposed to many unhealthy working conditions such as long hours, irregular shift work, sleep disturbances, stressful conditions and unpredictable and harmful exposures to environmental pollution.,, Apart from the unhealthy working conditions, the personal behaviours of the drivers were also not health promoting. In the current study, more than half of the drivers were not having meals on time and consumed junk food in place of major meals many times during a week. Additionally, a shocking proportion of drivers (83.6%) revealed that they never exercised. Other studies also suggest that drivers may experience prolonged sitting and physical inactivity, with limited access to healthy foods.,, In another study done by Gany et al. on south Asian taxi drivers, almost all drivers described little to no physical activity and regularly eating unhealthy food at work. Drivers reported that common barriers to exercise included lack of motivation, opportunity and time, exhaustion and not seeing any benefit of exercise. The information on healthy living should be disseminated through multimedia like television, newspapers and mobile phones. Places like eateries and restaurants, taxi stands, airports and resting points that are frequently visited by drivers should also be included in providing them health education.
In the present study, almost one-third drivers have reported the use of tobacco either in smoking form or chewable form. The findings are congruent with that of another study by Gany et al. where approximately 30% of drivers reported ever using tobacco (including cigarettes, cigars, hookahs and smokeless tobacco). However, a study done by Shetty et al. in Bengaluru city of India, reported that 70.88% of cab drivers were consuming tobacco in any form and long working hours, working at night and family members consuming tobacco were significant risk factors for tobacco use among cab drivers. The lower proportion of drivers consuming tobacco in the current study may be due to non-inclusion of night shift drivers, who report a higher use of tobacco to improve concentration and to reduce sleepiness. Tobacco use in India is a major public health problem as around 1 million people die every year due to tobacco consumption. Interventions at the worksite and in the community are powerful ways to modify the risk profiles of populations. Use of support groups or peer groups at work along with health promotion by higher management may be useful in curbing smoking habits of people.
In the present study, one-fourth of the drivers were suffering from GI disorders and 38% were suffering from musculoskeletal disorders like back pain and knee pain. Similar proportion of drivers (24%) have reported having GI problems in another study. The drivers suffering from lower back pain were much higher in other studies (60% or more)., While, another study reported much lesser proportion of taxi drivers with lower back pain. The main reasons of higher physical morbidity is driving for long hours, resting in the car in uncomfortable positions, frequent use of clutch during traffic situations, little physical activity and unhealthy eating.
In the current study, more than half of the drivers screened positive for depression, however, none of the independent variable was found to be significantly associated with the same. In a study done on truck drivers of Brazil, the prevalence of depression among truck drivers was 13.6% and depression was associated with younger age, low educational, use of stimulants and wage earning. In another study done on truck drivers of USA, 26.9% were suffering from depression, 20.6% from chronic sleep disturbance and 13% from other emotional problems.
In the current study, almost one-third are suffering from anxiety. The findings are different from a study done on truck drivers of USA, where 14.5% suffer from anxiety. In the current study, 36% drivers had variable degrees of stress. The findings are congruent with a study done by Davidson et al. in Australia on taxi drivers which reported that one-third (33%) of drivers had very high (K10 ≥30) levels of distress and 28% had high (K10 = 22–29) levels of distress. The levels of stress, however, were reported to be very high among drivers of public transport in Belgium where 70.2% drivers revealed their job to be stressful. Los Angeles and New York city taxi driver data also highlight poor working conditions, high stress, safety fears and unstable income., The lesser levels of stress reported in the current study is due to the use of a tool, which used proxy statements to measure stress rather than asking about stress itself. The results of the current study have shed light on the emotional and occupational health of cab drivers which is a highly underserved occupational group. Mental health should become a focal point of health interventions among the drivers and emphasis should be laid on promotion and prevention of mental health. Mental diseases should be assessed and treatment should be provided.
Health seeking among drivers in the current study is poor. More than two-third of the drivers never had a health check up in the last 1 year. When asked about self-reported diabetes and hypertension, only one driver had been diagnosed with diabetes and three with hypertension. The proportion is much lower than that reported in another study, where 28% of drivers had hypertension and 14% had diabetes. Very few cases of chronic disease in the current study does not suggest absence of hypertension or diabetes among the drivers but mere non-diagnosis.
In the current study, none of the drivers had any health insurance provided by the company. In other studies the proportion of drivers with health insurance was higher (46–50%)., Health insurance cover in general population is low in India, the findings of current study reinforces the same. Moreover, drivers are generally considered independent contractors and thus not 'employees.' The vast majority are therefore not entitled to employer-sponsored health insurance options through taxi companies.
The study may have certain limitations. The sample size is small and due to time constraints, the interview had to be kept short, which may have led to neglect some important independent variables that affect mental and physical health. A very important factor that may affect mental health status is personality trait – which was not assessed due to time constraints. The tool used to assess mental health was a mere screening tool and actual prevalence of depression, anxiety or stress could not be assessed. Owing to safety issues, the interview was only conducted during the day and this may have led to a bias due to non-inclusion of night shift drivers. Despite this, the study has good generalisability to other cab drivers of the city or other major cities of the country. Available data still provides valuable information on an understudied occupational group.
| Conclusion|| |
The extent of mental and physical morbidities found in this study is profound and underscores the need to address driver's health through multiple levels of intervention. Unique characteristics of this job and demographic profile of drivers mandate highly specialised interventions. Their mental health problems should be addressed through screening, counselling and promotion of relaxation techniques like yoga. There is also an urgent need to promote healthy eating habits, taking walking breaks, cessation of use of habit-forming substances and frequent health check-ups. The cab companies need to implement measures to improve job satisfaction, particularly among the wage-earning drivers – as this is likely to improve their mental health. Improving health insurance coverage for this group of workers is recommended. Larger cohort studies should be done to study various aspects of driver's health and collaboration with hospitals should be done so that they can conveniently seek care.
The authors would like to thank all study subjects for their precious time and participation.
The authors declare no competing interests.
Akanksha Rathi has conceptualised the study, collected the data and written the manuscript. Vikas Kumar has done data analysis and has revised the manuscript, Amrita Singh has done data collection and analysis and Panna Lal has revised and finalised the manuscript.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Elshatarat RA, Burgel BJ. Cardiovascular risk factors of taxi drivers. J Urban Health. 2016;93:589-606.
Miyamoto M, Konno S, Gembun Y, Liu X, Minami K, Ito H. Epidemiological study of low back pain and occupational risk factors among taxi drivers. Ind Health 2008;46:112-7.
Raanaas RK, Anderson D. A questionnaire survey of Norwegian taxi drivers' musculoskeletal health, and work-related risk factors. Int J Ind Ergon 2008;38:280-90.
Davidson S, Wadley G, Reavley N, Gunn J, Fletcher S. Psychological distress and unmet mental health needs among urban taxi drivers: A cross-sectional survey. Aust N
Z J Psychiatr 2018;52:473-82.
Vézina M, Gingras S. Work and mental health: Risk groups. Can J Public Health 1996;87:135-40.
Assari S, Moghani Lankarani M, Dejman M, Farnia M, Alasvand R, Sehat M, et al
. Drug Use among iranian drivers involved in fatal car accidents. Front Psychiatr 2014;5:69.
Borowsky A, Shinar D, Oron-Gilad T. Age, skill, and hazard perception in driving. Accid Anal Prev 2010;42:1240-9.
Clarke DD, Ward P, Bartle C, Truman W. Older drivers' road traffic crashes in the UK. Accid Anal Prev 2010;42:1018-24.
Ryb GE, Dischinger P, Kufera J, Soderstrom C. Smoking is a marker of risky behaviors independent of substance abuse in injured drivers. Traffic Inj Prev 2007;8:248-52.
Gururaj G, Varghese M, Benegal V, Rao GN, Pathak K, Singh LK, et al
. National mental health survey of India, 2015–2016. Prevalence, Pattern and Outcomes. National Institute of Mental Health and Neuro Sciences; 2016.
Kallakuri S, Devarapalli S, Tripathi AP, Patel A, Maulik PK. Common mental disorders and risk factors in rural India: Baseline data from the SMART mental health project. BJPsych Open 2018;4:192-8.
Kaneko SY. Mental health survey of truck drivers. Nihon Eiseigaku Zasshi 2014;69:199-204.
Shrivastava BM. Tobacco use among police personnel in Indore, India. In: Lu R, Mackay J, Niu S, Peto R, editors. Tobacco: The Growing Epidemic. London: Springer; 2000.
Ansari-Moghaddam A, Habybabady RH, Shakiba M, Mirzaei R, Shahriyari F, Aghaei S. Predictors of initiation, continuation and transition of drug use in south-eastern Iran. J Pak Med Assoc 2012; 62:698-703.
Antony MM, Bieling PJ, Cox BJ, Enns MW, Swinson RP. Psychometric properties of the 42-item and 21-item versions of the depression anxiety stress scales in clinical groups and a community sample. Psychol Assess 1998;10:176-81.
Ng F, Trauer T, Dodd S, Callaly T, Campbell S, Berk M. The validity of the 21-item version of the depression anxiety stress scales as a routine clinical outcome measure. Acta Neuropsychiatrica 2007;19:304-10.
Chan RC, Xu T, Huang J, Wang Y, Zhao Q, Shum DH, et al
. Extending the utility of the depression anxiety stress scale by examining its psychometric properties in Chinese settings. Psychiatr Res 2012;200:879-83.
Musa R, Fadzil MA Zaini Z. Translation, validation and psychometric properties of Bahasa Malaysia version of the depression anxiety and stress scales (DASS). ASEAN J Psychiatr 2007;82:82-9.
Dinges DF, Pack F, Williams K, Gillen KA, Powell JW, Ott GE, et al
. Cumulative sleepiness, mood disturbance, and psychomotor vigilance performance decrements during a week of sleep restricted to 4-5 hours per night. Sleep 1997;20:267-77.
Platek AE, Szymanski FM, Filipiak KJ, Ozieranski K, Kotkowski M, Tyminska A, et al
. Prevalence of depressive disorders in professional drivers – epidemiologic subanalysis of the RACER study. Psychiatr Pol 2016;50:859-71.
Tamrin SB, Yokoyama K, Jalaludin J, Aziz NA, Jemoin N, Nordin R, et al
. The Association between risk factors and low back pain among commercial vehicle drivers in peninsular Malaysia: A preliminary result. Ind Health 2007;45:268-78.
Bawa MS, Srivastav M. Study of the epidemiological profile of taxi drivers in the background of occupational environment, stress and personality characteristics. Indian J Occup Environ Med 2013;17:108-13.
] [Full text]
Wu S, Deng F, Niu J, Huang Q, Liu Y, Guo X. Association of heart rate variability in taxi drivers with marked changes in particulate air pollution in Beijing in 2009. Environ Health Perspect2008;118:87-91.
Brucker N, Charao MF, Moro AM, Ferrari P, Bubols G, Sauer E, et al
. Atherosclerotic process in taxi drivers occupationally exposed to air pollution and co-morbidities. Environ Res 2014;131:31-8.
Apantaku-Onayemi F, Baldyga W, Amuwo S, Adefuye A, Mason T, Mitchell R, et al
. Driving to better health: Cancer and cardiovascular risk assessment among taxi cab operators in Chicago. J Health Care Poor Underserved 2012;23:768-80.
Gany FM, Gill PP, Ahmed A, Acharya S, Leng J. “Every disease…man can get can start in this cab”: Focus groups to identify south Asian taxi drivers' knowledge, attitudes and beliefs about cardiovascular disease and its risks. J Immigr Minor Health 2012;15:986-92.
Burgel BJ, Gillen M, White MC. Health and safety strategies of urban taxi drivers. J Urban Health2012;89:717-22.
Gany F, Bari S, Gill P, Ramirez J, Ayash C, Loeb R, et al
. Step on it! Workplace cardiovascular risk assessment of New York City yellow taxi drivers. J Immigr Minor Health 2016;18:118-34.
Shetty P, Khargekar NC, Debnath A, Khargekar NR, Srivastava BK, Hakeen NEF. Determinants of tobacco use and prevalence of oral precancerous lesions in cab drivers in Bengaluru City, India. Int J Prev Med 2017;8:100.
] [Full text]
Jha P, Jacob B, Gajalakshmi V, Gupta PC, Dhingra N, Kumar R, et al
. RGI-CGHR investigators. N
Engl J Med 2008;358:1137-47.
National Institute for Occupational Safety and Health (NIOSH). Using Total Worker Health concepts to enhance workplace tobacco prevention and control. In: Afanuh S, Lee M, Hudson H. Cincinnati, OH: U.S. Department of Health and Human Services, Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health; 2015. DHHS (NIOSH) Publication No. 2015-202. Available from: http://www.cdc.gov/niosh/docs/wp-solutions/2015-202/pdfs/2015-202.pdf
. [Last accessed on 2018 Jul 11].
Yang Y, Fan XS, Tian CH, Zhang W, Li J, Li SQ. Health status, intention to seek health examination, and participation in health education among taxi drivers in Jinan, China. Iran Red Crescent Med J 2014;16:e13355.
Burgel BJ, Elshatarat RA. Psychosocial work factors and low back pain in taxi drivers. Am J Ind Med 2017;60:734-46.
da Silva-Júnior FP, de Pinho RS, de Mello MT, de Bruin VM, de Bruin PF. Risk factors for depression in truck drivers. Soc Psychiatry Psychiatr Epidemiol 2009;44:125-9.
Shattell M, Apostolopoulos Y, Collins C, Sönmez S, Fehrenbacher C. Trucking organization and mental health disorders of truck drivers. Issues Ment Health Nurs 2012;33:436-44.
De Valck E, Smeekens L, Vantrappen L. Periodic psychological examination of train drivers' fitness in Belgium: Deficits observed and efficacy of the screening procedure. J Occup Environ Med 2015;57:445-52.
Blasi G, Leavitt J. Driving poor: Taxi drivers and the regulation of the taxi industry in Los Angeles. Los Angeles, U.S.: UCLA: Institute of Industrial Relations; 2006.
Project CD. UNFARE taxi drivers and the cost of moving the city. New York, NY: Urban Justice Center; 2003.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]