PUTRAJAYA - As highways begin to fill and the annual Hari Raya Aidilfitri ‘balik kampung’ exodus gathers momentum, many Malaysians will embark on long journeys carrying more than just kuih raya and luggage.
They will also be relying on increasingly sophisticated driver-assistance technologies such as Adaptive Cruise Control (ACC) and Lane Keep Assist (LKA).
Now common in newer vehicles, these systems promise safer and less tiring journeys. But road safety experts warn that when misunderstood, such technologies may introduce a subtler risk, overconfidence.
The ACC automatically adjusts a vehicle’s speed to maintain a safe distance from the car ahead by accelerating or slowing down using sensors such as radar or cameras, while LKA helps keep the vehicle centred within its lane by detecting road markings and providing gentle steering corrections or warnings if the car begins to drift.
Head of the Road Safety Research Centre at Universiti Putra Malaysia, Assoc Prof Dr Law Teik Hua, said prolonged reliance on driver-assistance systems can reduce active monitoring and increase reaction times, a phenomenon known as automation complacency.
"This phenomenon occurs when drivers assume the system will handle hazards. When unexpected events arise, such as sudden obstacles or sensor failure, drivers may take longer to re-engage," he said.
The Society of Automotive Engineers International classifies vehicles equipped with ACC and lane centring technology at Level 2, meaning the system can control steering and speed simultaneously but requires the driver to continuously monitor the environment and be ready to intervene.
In controlled conditions, these systems, along with other advanced driver assistance systems (ADAS), can enhance safety performance. Festive travel, however, is rarely controlled.
The Aidilfitri exodus typically brings dense congestion, abrupt braking, aggressive lane cutting and motorcycles filtering between vehicles. In such dynamic traffic, sudden cut-ins can challenge ACC response times, while faded or unclear lane markings may limit lane keep assist effectiveness.
"Drivers must understand that these are Level 2 assistance systems. The human driver remains fully responsible," Law stressed.
International research echoes that warning. A report by the Insurance Institute for Highway Safety (IIHS) found that partial automation features are best understood as convenience technologies rather than standalone safety systems.
The study and related research warned that reliance on partial automation can contribute to driver overconfidence and disengagement, with empirical work suggesting that some motorists may take greater risks because they feel the system will handle driving tasks.
Fatigue further complicates matters. Extended highway journeys, often undertaken at night during festive periods, create monotony.
Law said that although semi-autonomous features reduce physical workload, cognitive workload remains.
"When drivers are tired and at the same time confident about the semi-autonomous car, they might react slowly to an emergency,” he said, adding that motorists should ensure they are well-rested before long journeys.
Malaysia’s tropical weather also tests system reliability, whereby heavy rain can interfere with radar and camera sensors, reducing object and lane recognition. Sun glare may affect camera-based systems, while worn or poorly maintained road markings, particularly on secondary roads and in construction zones, can impair lane-keeping performance.
Law noted that driving culture presents another layer of unpredictability, with frequent lane changes, short following distances and motorcycle filtering triggering sudden braking responses from ACC when vehicles cut in, potentially surprising trailing motorists and increasing rear-end risk.
He advised motorists to treat assisted-driving features strictly as support tools.
"Drivers should disengage ACC and lane keep assist during heavy rain, floods, construction zones, sharp curves or complex urban traffic. Both hands must remain on the steering wheel, safe following distances should be maintained, especially in wet conditions, and sensors should be kept clean to ensure proper detection.
Technology can assist, but it cannot replace responsibility," he added.
As families travel home to celebrate, advanced systems may ease fatigue. But safe arrivals will still depend on something far more fundamental than automation: alert, attentive human judgment behind the wheel. - BERNAMA