Road safety systems have traditionally relied on chemical testing to identify whether a driver has consumed alcohol or other substances. But the presence of a substance in the body does not necessarily tell us how much a person's ability to drive has actually been affected. This distinction between intoxication and impairment is at the centre of the second paper in Seeing Machines' technical series on driver intoxication.

The paper explores how camera-based Driver Monitoring Systems (DMS) can take a different approach by observing the driver's functional state in real time. Instead of trying to determine which substance is responsible for a driver's condition, the system looks for visual and behavioural indicators that suggest reduced driving capability. This is particularly relevant when impairment may result from cannabis, combinations of substances or other factors that cannot easily be addressed through a single chemical threshold.

This cause-agnostic approach is interesting because it shifts the focus from identifying what is in the driver's body to assessing whether the driver is currently capable of driving safely. A DMS can continuously monitor changes in the driver's condition and potentially trigger an intervention when the risk becomes significant. The paper presents this as a complement to existing roadside enforcement rather than a replacement for chemical testing.

The development fits into a wider evolution of in-vehicle safety technology. Driver monitoring is increasingly moving beyond relatively simple measurements such as eye closure or gaze direction towards a more comprehensive assessment of driver state. This becomes particularly important as vehicles gain more advanced ADAS functions, because the system needs to understand not only what is happening around the vehicle but also whether the person behind the wheel remains able to supervise it effectively.

As vehicles become more automated, understanding the driver's condition will become increasingly important. A vehicle may be capable of performing many driving tasks itself, but the transition between human and automated control still depends on the human being sufficiently attentive and capable of responding when required. Real-time monitoring could therefore become an important part of the safety architecture of increasingly automated vehicles.

You can read the full article here. SEEING MACHINES. Technical Paper Series – Intoxication: Part 2 [online]. April 2026 [cited 2026-08-16]. Available from:https://seeingmachines.com/technical-paper-series-intoxication-part-2/