INTERNATIONAL TRUCK STOP - Researching safety… by accident

Tuesday, November 13, 2018

Ever wondered what’s the biggest cause of road traffic accidents? Try the person behind the wheel. Volvo Trucks’ latest safety report yields some thought-provoking stats…

Road safety, and especially what causes us to do daft things once we get behind the wheel, is an interesting topic. When it comes to informed debate on HGV accident statistics, a go-to source is Volvo Trucks’ Safety Report, an infrequent, though highly informative analysis of European Union road accident data involving HGVs of all makes, not just Volvo. The report is compiled by Volvo Trucks Accident Research Team (ART), one of the main driving forces behind increased traffic safety at the Swedish truck manufacturer for the past 49 years. Since its creation in 1969, ART has studied and analysed more than 1700 accidents involving Volvo trucks, using the information gained “…as a basis for the development of our products to become as safe as possible”.

Incidentally, Mercedes- Benz operates a similar in-house accident research unit that attends collisions involving trucks with the three-pointed star, analysing the details, and seeing how the safety systems it has developed have proved their worth in the field. When it comes to what actually causes an accident, the 2017 Volvo Trucks Safety Report confirms that, while accidentcausing scenarios are complex: “It is seldom vehicle technical failure or [road] infrastructure solely that causes an accident. Human factors are involved in approx. 90% of all cases.” Interestingly, it then adds “…human factors are not necessarily the same as human errors. For instance, if you look in the side mirror for a split second and the car in front of you suddenly stops, you may not react in time to apply the brakes.”

That sounds to me like the kind of scenario that Autonomous Emergency Braking Systems (AEBS) were designed to handle. Since 2015 AEBS has been mandatory on most new trucks sold in Europe above 8 tonnes fitted with rear air suspension (with some notable exemptions), while this November the breakpoint comes down even further to 3.51 tonnes for trucks with all types of rear suspension. As to what constitutes ‘human factors’, the report lists three examples: Inattention; lack of risk awareness; and misjudgement of complex traffic environments. Commenting on the first, it says: “It’s difficult to know exactly how many accidents are caused by inattention. Research suggests it’s a common cause, one that’s been increasing over the past few years.” Given the growing number of distractions in today’s world, we shouldn’t be surprised. Inattention is certainly a typical contributory factor in two of the most common ‘Type A’ accidents – categorised in the report as solely involving HGVs, resulting in an injury or fatality to the occupants of the truck.

(‘Type B’ accidents involved cars and HGVs). The first involves a single truck driving off the road, often, though not necessarily, followed by a rollover or a collision with an object (35-40%). The second is where one truck drives into the back of another (15-20%). Naturally, inattention cuts both ways – as any truck driver will tell you who’s just had a pedestrian staring into a mobile device step out in front of them. The report clearly identifies that as a problem. Under the heading ‘Smartphones steal attention’ it says: “17% of all pedestrians use their smartphones while crossing the roads and fail to pay attention to the traffic situation.” But then again, pedestrians aren’t the only ones who can be distracted by a smartphone… are they? Moving on to the above-mentioned ‘lack of risk awareness’, a good example amongst HGV drivers would be those who consistently refuse to ‘belt up’.

While no one would dispute seatbelts save lives, the report says: “Despite this, drivers of HGVs show lower usage rates [compared with car drivers] even though strengthened HGV cabs can only protect their occupants if they are properly belted.” Apparently one of the common reasons given for not wearing a belt is that it’s “Too much work” or “it takes too long.” Getting more HGV occupants to wear a seatbelt is one of the report’s key recommendations.

Personally, I wouldn’t drive a truck without wearing a seatbelt, and wouldn’t be happy if anyone else in the cab wasn’t wearing one either. There’s a famous Volvo Trucks video showing two crash test dummies in the cab of an FH filmed during a rollover test. One has a seatbelt on, the other doesn’t. As the truck tumbles down a slope the unrestrained dummy is flung all over the place before finally being ejected through the front windscreen. The belted dummy, on the other hand, stays put thanks to their seatbelt. Now here’s the kicker. Having seen the video a couple of times I was asked by one of Volvo’s safety experts “Which dummy survived the roll-over?” ‘Easy peasy’ I thought, “The one with the seatbelt on.” He smiled knowingly, and then re-ran the video, pointing out the bit where the unrestrained dummy flies across the cab and smashes into the one wearing the seatbelt with such force that had it been for real, both occupants would have sustained severe injuries. Food for thought. One of the more surprising findings of the report is that “A vast majority of all severe accidents occur during daytime in fair weather.” You’d have expected night-time and in winter. However, the simple explanation is that there are more cars and HGVs on the road during daytime – so consequently accidents are more frequent. Drill down and you find another surprise. Dry roads are the most prevalent road conditions of all types of accidents, which the report says “correlates with the fact that most accidents occur in fair weather”. So what’s going on there? Dry roads offer the best braking surface, though clearly not for many drivers.

It’s sobering to know that according to the Volvo report, “30-35% of all HGV collisions are ‘Type C’ accidents” i.e. those involving a vulnerable road user (VRU) – be they pedestrian, cyclist or motorcyclist – resulting in death or serious injury. And the most common (30%) of them involve a collision between a VRU and the truck at an intersection where the VRU suddenly crosses in front of the truck. Typically it’s down to inattention on the part of the VRU, or the HGV driver, a lack of judgement, or misjudgement of the truck’s speed by the VRU, and limited visibility of the VRU from the cab. Close behind (20%) is the classic HGV turning manoeuvre (right in a left-hooker and left in a right-hooker) where the front or side of the truck strikes the VRU as the gap between the truck and a cyclist or pedestrian closes up as the vehicle turns. Again, typical causes include limited visibility from the cab nearside, a lack of communication between the VRU and driver, or inattention and misjudgement on the part of the VRU.

However, as the report’s authors acknowledge, “Accidents involving VRUs are very complex since VRUs are somewhat unpredictable. They can move in ways that leave little room for a driver to react. Hence, accidents happen even when the driver is focusing fully on the traffic.” Amongst the ‘Prioritised Areas for Improving Traffic Safety’, Volvo recommends further development of active safety systems like AEBS “to include scenarios involving VRUs, for example crossing accidents”. For the record, Mercedes- Benz’s latest generation optional Active Brake Assist 4 system (AEBS), available on its long haul Econic trucks and Setra coaches, already features a pedestrian detection function that automatically warns the driver of an imminent collision when one walks out in front of the vehicle, and simultaneously initiates partial braking. The system is active at speeds up to 50km/h.

Ultimately, as the report confirms, active safety systems don’t just mitigate an accident, they can also prevent it altogether. Moreover, the ongoing reduction in accidents involving HGVs in Europe shows that active safety systems like AEBS, adaptive cruise control (ACC), and electronic stability control (ESC) can be powerful allies in avoiding death and injury on the road.