What are driver monitoring systems?

When it comes to our roads, driver fatigue and driver distraction are killers.

Fatigue when driving is more serious than you might think, with tired drivers estimated to contribute to up to 20 per cent of all road crashes. Being awake for 17 hours impairs a driver to the same degree as someone with a blood alcohol concentration of 0.05.

Even though there are positive steps we can all take to avoid a fatigue-related crash, such as getting a good night’s sleep before driving, taking breaks at least every two hours, and not travelling for more than eight to 10 hours a day (sharing the driving as much as possible), there is also upcoming in-car technology to help us not drive when we’re too tired.

In a similar vein, driver distraction is another significant contributing factor behind many road traffic accidents. There are many potential sources of distraction both inside and outside the vehicle, but the technological advances of recent years – smartphones in particular – all too often tempt drivers to take their eyes off the road, with sometimes disastrous results. Studies have shown that drivers are three to 12times more at risk of crashing if they are also using their mobile phone while behind the wheel.

Driver monitoring systems (DMS) have been around in a simple form for a while, but there have been big improvements of late, according to the Victorian road safety body, the Transport Accident Commission (TAC).

The TAC’s Acting Manager, Road Safety Research, Insights and Evaluation, Dr David Young, explained: “DMS has evolved a lot recently, all the way from just monitoring the time you’ve been driving and prompting you to have a break, to now lots of vehicles that can actively monitor the driver’s attention, making sure they’re aware, making sure they’re paying attention and looking where they need to look.”

Young added that the DMS technology follows the existing trend of automotive safety technology more generally; it’s beginning to count in the software as much if not more than the hardware. “In many ways, DMS development has been in response to vehicle safety technologies,” he said. “Initially these technologies were about how the vehicle performed during a crash and how it protected its occupants, but now they’re going all the way to active support systems.

“Driver monitoring needs to evolve as well because as active systems come into the car the driving task is going to change; the vehicle’s ability to ensure that the driver is actively involved in the driving task, and ready and able to make decisions, is really important.”

With the latest DMS technology, the system decides when it’s time to alert the driver if it assesses that they are too tired or distracted – if required, the driver is warned with a visual and audible warning. Often, the first warning is a message on the instrument cluster accompanied by a chime. As you would expect, if the message is ignored and erratic driving continues, the warnings become more frequent, asking the driver to respond with the correct action. The DMS will reset when the vehicle has stopped and the driver leaves the car to have a break, or when the driver begins a new trip.

The more advanced DMSs on the market use inputs from a camera trained on the driver as well as the existing Advanced Driver Assistance Systems (ADAS).

These ADAS platforms are often mentioned as key technological vehicle safety improvements. ADAS includes things like autonomous emergency braking (AEB), lane keep assist, lane departure warning, blind-spot detection, and other types of crash-prevention technologies. However, these technologies work best when combined with DMS.

For example, a car using DMS in combination with an AEB system would know if a driver is distracted. In this case, the car can increase the distance before the AEB system automatically initiates braking. Similarly, lane-keeping assistance can become more sensitive and take over more vehicle control when the vehicle detects a distracted or drowsy driver.

Driver face monitoring systems deduce the symptoms of fatigue and distraction from head and face movements. These include the period of time that eyelids are closed, eyelid aperture (opening distance), eye blink rate, blink speed, gaze direction, eye movements, yawning, head nodding and head orientation.

The most advanced DMSs utilise a clever set-up, because not only do they do the obvious thing by constantly checking for the signs of fatigued or distracted driving behaviour, such as sleepy eyes, over-correcting steering or constant speed changes, but they also adapt to a particular driver’s driving style.

In the same way an adaptive automatic transmission will change shift points according to driving style, so to does the DMS ‘learn’ driving styles so it then can detect any out-of-the-ordinary driving. It learns the driver’s typical driving style in the early part of a journey and so if there is a significant change in driving later on, the DMS sets off the driver alert functions.

Advanced DMSs can use data produced by the lane departure warning system’s forward-facing camera to good effect. Yet the DMS is ‘looking’ for something more subtle than lane departure; the system actually compares the movement of the car in the lane compared to data collected at the start of the journey. In particular, the system is looking for increased levels of drifting within the lane, which is an often-seen behaviour in drivers who are getting too tired to drive.

DMS will increasingly become a standard safety feature as ANCAP steps up its assessment of DMS as part of its ADAS testing. Requirements will centre around distracted and drowsy driving to begin, and it is anticipated that later it will require the DMS to have the capacity detect alcohol and drug impairment.

Dr Young explained that the technology is developing so fast that further investigation of its safety potential is required. “We’re at the stage where we are trying to learn how the technology supports drivers, what level of support it provides, and how well it functions. We’re keeping an eye on how the industry is developing.

“It is anticipated that driver monitoring systems will be an important layer in ensuring the safety of drivers, and this will be especially important as vehicles continue to do more for drivers.”