Collision mitigation07 March 2016

Braking and stability systems have been influenced as much by legislation as engineering innovation, but the new technology comes in several different strengths. Ian Norwell explains

The brake used to be the middle pedal, of course, but with the clutch gone the way of so much driver control and influence, there are now only two. And with the accelerator already working part time, progressive automation may yet challenge even these in the driver’s footwell.

It’s a moot point whether AEBS (advanced emergency braking systems) legislation would have arrived as early as last November had the technologies not been pushed through by OEMs and system suppliers. Either way, that November deadline marked the point when new trucks became better equipped with safety systems than the average car.

In fact, the EU’s drive to mandate these safety systems was spurred on by a white paper on European transport policy in 2011. Its target was to halve the number of fatalities on EU roads by 2020, and move close to zero fatalities by 2050. Advanced driver assistance systems (ADAS) were seen as the obvious route, so Regulation 661/2009/EC mandated fitting safety features in a phased introduction. Electronic stability control (ESC) arrived in November 2014, with an orderly queue following. Lane departure warning (LDW) and AEBS became mandatory for new type approvals back in 2013.

The payback for system manufacturers such as Wabco and Bosch is a slow burn with a hoped-for explosion of uptake at the end. Their accountants need a special kind of tolerance. A lifetime ago, when ABS (anti-lock braking system) was developed, take-up rose gradually to around 4% of registrations. When it became mandatory (for commercial vehicles in October 1991), ABS had already been in production for well over 30 years.

That certainly was a slow burn, but the fuse is getting shorter. Yes, AEBS arrived in commercial vehicles as a mandatory fitment last November, but it’s only been available as an option for a few short years.

That said, some industry professionals worry about a perception that the equipment in a post-November 2015 registered truck, is a full emergency brake stop. That’s not the case. As DAF Trucks demonstration driver and trainer Mandy Wannerton says: “Spectacular video clips that show full-pressure automated stops have been circulating for a while, and many drivers mistakenly assume that it’s what they will have.”

Wannerton concedes that some trucks may be fitted with full collision avoidance, but insists they will be a rarity. “The vast bulk of systems in trucks registered from November 2015 are better described as collision mitigation. They do not provide that complete halt.” Clearly, drivers shouldn’t be modifying safety-conscious driving styles simply because AEBS is fitted, but she’s right to make the distinction.

Among suppliers leading the charge for AEBS is Wabco. Its accountants must now be looking forward to a return on substantial R&D investments, given the firm launched its EBS for CVs back in 1996. At the time, it represented an exceptional advance, resulting in some of the most dramatic test track brake demonstrations on the planet.

But that led to ESC attracting more legislation. “Now, to meet the European Commission’s requirements for AEBS, a haptic or acoustic warning to the driver needs to be provided no later than 1.4 seconds before the start of emergency braking,” says Wabco chief technology officer Dr Christian Wiehen.

That’s the precursor. Current AEBS legislation is then framed as a two-step process, both based on collision mitigation, not avoidance. Step one (November 2015 registrations onwards) has two performance expectations to limit an impact firstly on slow moving vehicles, and secondly on stationary traffic. It applies to vehicles over 8 tonnes with air brakes and air suspension. Step two AEBS (November 2018) increases the performance requirements, but also brings down the weight class to 3.5 tonnes.

Step three has yet to be framed, but this is likely to be full-fat collision avoidance. “For now, AEBS step two parameters will mean that a vehicle driving at 80kph should not impact a vehicle driving at a speed of 12kph,” explains Wiehen. “The mandatory speed reduction [from step one] will be increased to 70kph. The speed reduction for a stationary vehicle will also be increased to 20kph.”

Clearly, that’s mitigation, not avoidance. Log on to YouTube, however, and the star of the show is full collision avoidance AEBS. But there’s no legislation yet framed to introduce it, and unless you’ve paid for the optional extra, it won’t be on your truck.

There are two technical and commercial challenges here. First, truck makers need to integrate expensive kit with the lowest possible price impact. New model ranges offer a good opportunity to soften the blow. Secondly, though, system developers need to get full AEBS onto the statute books to drive uptake.

Truck makers aren’t standing in the way, and those who actively promote safety already offer full-fat systems. No surprises: you can order them on a Volvo FH and on a Mercedes-Benz Actros, for example. Meanwhile, other truck makers are ahead of the game, too – among the DAF and Iveco, which have gone straight to the 2018 mandated levels, by-passing step one.

“Our latest AEBS – OnGuardActive – is capable of delivering full braking on moving and stopping vehicles, as well as partial braking on stationary vehicles, and it can bring the vehicle to a complete stop,” asserts Wiehen. “Its 77GHz radar sensor offers up to five-times the bandwidth of 24GHz systems already on the market.” And he adds that the system's dual-mode function addresses both long range and adjacent lane views. In fact, it analyses traffic up to 200 meters ahead, recognising critical driving situations earlier than its predecessors.

But how much extra will fleet managers pay for top level protection? Mercedes ABA3 (active brake assist) costs £3,000 and the Volvo equivalent, forward collision warning (FCW), is £2,500. It’s not difficult to see both as reasonable, but the creep of legislation suggests it will take time to make even step one systems commonplace. The result: “As a truck is maybe five years in first ownership and then often sold to eastern countries, which also operate in the EU, it will probably take 10 years until ADAS has been fitted in every CV on European roads,” opines Wiehen.

During this period, differentials in braking capability will widen, with older non-AEBS and some (albeit rare) examples of ABA3 fleets sharing road space. If these extremes are driving in the same lane, then less-well-equipped following vehicles could be at risk. That’s certainly no argument for non-fitment, but it could make sense to mandate pulsing LED brake lights on trailers pulled by ABA3-equipped trucks, giving their poor relations a sporting chance.

Ian Norwell

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Related Companies
Bosch Ltd
DAF Trucks Ltd
Iveco Ltd
Mercedes-Benz UK Ltd
Volvo Group UK Ltd
WABCO Automotive UK Ltd

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