Our results show that DWI, marijuana along with stimulant pill use is a major issue in the commercial driver population of Pakistan. Currently, owing to the fact that sale and use of alcohol is illegal in the Muslim dominant Pakistani population, alcohol use while driving is not considered a major risk factor for road traffic injuries. This common belief is contradictory to our study findings which show up to 10% of truck drivers involved in alcohol use while driving. Our estimates are based on self reports, and as the practice of alcohol use is illegal and frowned upon in general society, we can safely assume that our findings are underestimated and the actual problem is of a greater magnitude. Our results show higher use of alcohol and marijuana in truck drivers compared to bus drivers. A possible explanation for this could be the conditions in which these two different groups drive. Bus drivers transport passengers in their vehicles resulting in there being less of a chance for the driver to engage in such activities without being reprimanded by the passengers.
Prevalence of DWI and marijuana use among commercial drivers is high in Pakistan compared to other countries. Studies on commercial drivers also show lower estimates compared to our study (0.5%-4.9%) [20
]. This difference may be due to lapses in the enforcement of drug and alcohol use laws by the Pakistani highway police. Some western studies also show high prevalence of substance abuse but these findings are likely to be over-estimated as they have been done in drivers suspected and then checked for substance abuse by the traffic police [30
The drivers' opinions on why alcohol and marijuana is used indicate a lack of awareness of the hazards associated with this practice. Most drivers believed that substance abuse relieves fatigue, makes the journey easier, and even prevents sleepiness, although sleep debt accumulates and cannot be relieved without normal restorative sleep [32
]. This presents us with an avenue for intervention to reduce substance abuse in this population. Awareness campaigns for behaviour modification are known to be effective, especially when coupled with promotion of alternative behaviours [33
]. The success of these campaign has been greater when they are combined with proper enforcement of stringent laws on drunk driving and substance abuse, and improved awareness of these laws and consequences of violations [33
Laws against DWI are ineffective in the country owing to the lack of use of methods such as random breath analyzer tests and blood tests on drivers suspected of DWI [2
]. Evidence of reduced fitness to drive as a consequence of drug consumption is essential for proper law enforcement [35
]. Pakistan still does not have a law specifying the allowable blood alcohol concentration of drivers on the road. Designating a BAC level, random checks and breathalyzer tests on these drivers on the road, combined with appropriate awareness campaigns may prove to be effective to resolve this dilemma [17
]. It is also important to note that regulations need to be enforced not just on the roads but also in the commercial transport organizations which hire the drivers to transport goods or passengers. Regular checks of drug and alcohol should be carried out in all drivers working for such companies for continued employment and the results should be available to law enforcement authorities.
Our results show significant variations in substance abuse among drivers of different ethnicities and socioeconomic strata. These findings indicate psychosocial elements influencing the use of drugs and alcohol in this population which were not explored in our study. Further investigations looking into this aspect may clarify the relationships between social, cultural and psychological risk factors for DWI and provide critical information for targeted and appropriate interventions.
The commercial drivers of large vehicles are a mobile population, spending most of their time on the road and stopping at segregation points from time to time. Our study was done at one of the biggest bus/truck stations in the country, lying on the Karachi-khyber route which runs across the country. The drivers stopping at this point are representative of the Pakistani large vehicle commercial driver population. Furthermore, we used time location cluster sampling, a type of probability sampling for mobile populations, minimizing any selection bias in our results. Our study included general commercial drivers of large vehicles driving on highways, giving us the prevalence estimates for this population and not only of those involved in crashes. This information is not frequently seen in the scientific literature. A limitation of the study is that we did not assess blood alcohol levels and instead resorted to self reporting of the practice by the drivers. There is a high level of agreement between reported and observed information on crashes and RTIS [36
] seen but reported information on illegal or socially unaccepted activities such as substance abuse while driving is generally under-reported [37
]. Considering our objectives and the fact that alcohol use is illegal by law, and disliked in the Muslim dominant Pakistanis society, we believe that self reported alcohol use while driving is a reasonable indicator for the presence of DWI and marijuana use in this population. It can be inferred that the actual problem may be greater than what our study recorded.