Driving under the influence: the difference between drugs and alcohol

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Driving under the influence: the difference between drugs and alcohol

13 HOURS AGO
Letter to the Editor

The persistence of the alcohol-versus-drugs debate reflects gaps in knowledge, enforcement asymmetries and cultural attitudes

From P Sundramoorthy


The belief that driving under the influence of alcohol is inherently “worse” than drug-impaired driving is widespread in Malaysia but from a criminological perspective, this hierarchy is neither straightforward nor particularly useful.


It reflects more about social perceptions, enforcement patterns and cultural narratives than the actual risks posed by different substances.

Recent high-profile vehicular manslaughter cases have intensified public anger, often accompanied by calls for harsher punishments, including the death penalty. Such reactions risk oversimplifying a complex issue.


At its core, impairment regardless of substance is the central concern. Alcohol has long dominated road safety campaigns and enforcement strategies. Alcohol-impaired driving is highly visible and heavily stigmatised. However, this visibility can create a cognitive bias; what is more frequently detected is often assumed to be more dangerous.

Drug-impaired driving by contrast, remains less visible and under-examined. Unlike alcohol, which typically produces predictable depressant effects, drugs have diverse and sometimes contradictory impacts.

The number of drug users in Malaysia is significant. A larger population of drug users increases the likelihood that some individuals will drive while impaired.

In certain contexts, this probability may exceed that of alcohol-impaired driving especially since alcohol consumption is often episodic, whereas some forms of drug use are habitual or integrated into daily routines.


While alcohol-impaired driving is more visible and frequently detected, drug-impaired driving may be more prevalent but under-recognised.

This reflects the “dark figure” of crime – behaviours that occur but are not fully captured in official statistics. The relative invisibility of drug-impaired driving should not be mistaken for lower risk but rather seen as an indicator of enforcement and surveillance gaps.

Legal and cultural factors also shape perceptions. Alcohol though regulated, is socially accepted in many contexts, whereas most drugs are criminalised and heavily stigmatised. Paradoxically, this can lead to an underestimation of drug-related risks in road safety discourse.

Detecting alcohol impairment is relatively straightforward but identifying drug impairment often requires more complex testing methods. This gap reinforces the perception that drug-impaired driving is less prevalent or less dangerous.


Alcohol impairment can be broadly measured through blood alcohol concentration, allowing for standardised legal thresholds. Drug impairment, however, is far less uniform. The same quantity of a drug can affect individuals differently depending on tolerance, metabolism and context. This complicates enforcement, prosecution and public messaging, reinforcing ambiguity around drug-impaired driving.

In response to tragic cases, there have been renewed calls to impose the death penalty for vehicular manslaughter involving impairment.

However, evidence consistently shows that the certainty of detection and punishment not the severity of punishment is the more effective deterrent.

The death penalty, in particular, has not been shown to produce a meaningful deterrent effect in cases involving impulsive or risk-laden behaviours such as impaired driving.

A more effective approach would focus on increasing the certainty and consistency of enforcement. This includes expanding roadside drug testing capabilities, improving forensic toxicology capacity, enhancing data collection and ensuring that enforcement is applied uniformly without regard to status or background.

When the public perceives that laws are enforced consistently and fairly, confidence in the justice system is strengthened, reducing the impulse to call for excessively punitive measures.

Both alcohol- and drug-impaired driving pose serious threats to public safety and require evidence-based responses.

Public education should emphasize that impairment is impairment, regardless of the substance and that driving under such conditions reflects broader issues of risk perception, accountability and social responsibility.

In a context where drug use is significant and often under-detected, drug-impaired driving may represent a more pervasive, if less visible, threat.

At the same time, calls for extreme punitive measures such as the death penalty risk diverting attention from more effective, evidence-based interventions.

A balanced and rational approach must recognise that crime is colourblind, deterrence depends on certainty rather than severity, and all forms of impaired driving must be addressed with equal seriousness and strategic clarity.



P Sundramoorthy is a criminologist at the Centre for Policy Research at Universiti Sains Malaysia and an FMT reader.