Eyes on the road, no hands upon the wheel

You're sitting at the lights when a Mercedes-Benz S-Class pulls up alongside. A quick scan of the car reveals there's nobody in the back seat – no up-and-coming starlets, no sleazy property developers, no disgraced politicians.

And then you check out the front seat and find... There's no one there either!

This is the sort of ideal-world scenario Mercedes-Benz is working towards. The prestige manufacturer is on a mission to make the autonomous car a reality. It may take decades and it won't happen everywhere at once, but the company that boasts it "invented the car" is developing advanced sub-systems that are the way of the future for personal transportation.

The latest S-Class, coded W222, is the production model that comes closest so far. During the international launch of the car in Toronto last month, motoring.com.au got behind the wheel of a simulator to see how it coped autonomously (in a controlled situation) with many of the day-to-day hazards we encounter on the road.

The simulator car negotiated a series of different urban and rural routes with hazards to be avoided along the way. In doing so it was aided by safety features like Distronic Plus with steering support. This system relies on radar and cameras to hold the car in a lane, pointing where it should for bursts of up to 10 seconds of hands-free motoring. At the 10-second mark it warns the driver to return at least one hand to the wheel. If the driver doesn't do so within five seconds the system will withdraw support.

Even if the driver has a heart attack at the wheel, the car's Pre-SAFE BRAKE active safety system will endeavour to avoid collisions altogether or at least mitigate the severity of the impact. The S-Class can distinguish pedestrians and cyclists at speeds up to 50km/h also.

Benz and other manufacturers are already well down the track of autonomous driving development, but Jochen Hermann, the Director of Driver Assistance Systems and Active Safety at Benz, was counselling ‘baby steps’ when he discussed the issue with motoring.com.au during the launch of the new S-Class.

Talk began with the new Adaptive High Beam Assist Plus system developed by Benz for both the recently introduced E-Class and the new S-Class.

Hermann is confident that the Benz headlight system will cope with all the vagaries of the Australian driving environment. Even in a challenging situation like the highly reflective directional signs on the outside of a bend on a country road at night, the S-Class system would manage to adjust its lights correctly, he said. The system will recognise that the signs are reflecting the car's own lights, rather than generating light of their own, but it will also dip the beams and save the driver being dazzled by the reflected light if necessary.

"If the situation is too complex, it will dim down," Hermann said by way of explaining that the system will opt for fully dipped as a default.

Onboard cameras and radar pick out different roadside furniture, but also they are now spotting parked cars, pedestrians, cyclists and animals. In fact, the S-Class Benz can distinguish a pedestrian standing next to a parked car at night, simply from the different heat signatures.

But while the S-Class will brake to a complete half for pedestrians, it will not brake for animals.

The S-Class has a spotlight that blinks and shines at pedestrians it regards as at risk of impact with the car. This is intended to alert the pedestrians of the car's proximity and closing speed. The spotlight is directed at both pedestrians and cyclists, but is aimed below the neck so that they are not blinded by it and placed at further risk.

Animals don't get the same courtesy, however, since they're more likely to be panicked by the blinking spotlight (which is normally accompanied by a red framing graphic in the instrument binnacle for the driver's information).

"We do not brake for animals," Hermann said.

In his considered opinion, it's better not to startle the animals, since they don't have a "learned response" to on-coming vehicles as humans do. They are just as likely to hop or run toward the car, rather than away from it – the animals, that is...

BRAKE WITH TRADITION
From there talk turned to collision avoidance of a different kind – Pre-SAFE BRAKE's facility to identify "a big chunk of metal", to use Hermann's words.

Not only does the S-Class’ autonomous braking system identify the threat posed by a car in front (and behind, for that matter), it will take pre-emptive action if the driver doesn't respond. Hermann says that the system will warn the driver, through "optical and acoustic" means, 2.6 seconds ahead of a forecast impact.

Should the driver neglect to respond, the car will apply up to 40 per cent of available braking effort, but hands partial control back to the driver. If, however, the driver is not applying enough pedal pressure to avoid the collision, Brake Assist will intervene – and bear in mind that unlike other systems, it's being guided by Pre-SAFE BRAKE's assessment of the impending crash rather than tyre slip registered through the stability control system.

This all happens about a second after the initial warning to the driver. If the driver has not responded at all to the warning with just 0.6 seconds remaining to impact, the system will autonomously initiate a full emergency brake event. At this point, the car's system is expecting impact and the braking is aimed at reducing the prospects of lives being lost in the worst case scenario.

The Benz system sounds a lot like similar systems offered by other prestige brands. This prompted a couple of questions to Hermann concerning how drivers accept the system in the real world.

The example given was one often experienced when a car equipped with a safety feature like Pre-SAFE BRAKE approaches from behind a car making a left turn. Often the driver will maintain speed, since it's clear that the vehicle in front will leave the intersection before the safe braking distance is reduced to the point where impact is assured.

But other systems will not recognise the future prospect of the car in front clearing the intersection before the car behind reaches it. Those other systems will immediately warn the driver by visual and audible alarms and immediately apply braking effort. As we discovered the next day, however, the Benz system is more sophisticated and will wait longer before taking the initiative away from the driver.

As demonstrated on a closed taxiway at a regional Canadian airfield, the Benz system would wait much later before applying the brakes, but would also ease off the brakes as soon as the driver took avoiding action by steering out of danger. So there's little to no chance that a vehicle following diagonally to the right of the Benz will slam into the side of it because the Benz driver has merged right suddenly, only to find the car is still braking for an emergency ahead in the left lane.

A NEW COURSE?
We came away convinced that there will be fewer false alarms troubling the drivers of new Mercedes-Benz models equipped with Pre-SAFE BRAKE.

But still, there was that niggling thought: Wouldn't emergency steering save more lives than emergency braking? Why not develop a system that is to steering what Brake Assist is to Emergency Braking – or even a fully autonomous steering system that can detect not only that "big chunk of metal" in front, but also other chunks of metal following... and place the car in a safe position on the road accordingly?

Remember Benz's own 1980-era ads when antilock brakes were introduced? Antilock-equipped S-Class W126 steered around boxes on a wet road, while the non-equipped car ploughed on straight ahead. Now imagine that instead of three boxes on the road ahead, there's a car making a left turn – and the driver of that car has decidedly suddenly not to proceed because there's a pedestrian crossing from the other side at a brisk walking pace.

Hermann's response is simple: "Steering is very difficult... Braking is very effective."

Already, numbers to hand have revealed that over the past five years, there has been an 18 per cent downturn in panel damage to the rear of Benz cars equipped with Pre-SAFE BRAKE.

"The guy behind you will thank you," Hermann adds, explaining that nose-to-tail accidents frequently involve more than two cars, because the impact of the second with the leading car has led to such sudden deceleration that cars behind can't stop in time. Pre-SAFE BRAKE not only warns the driver of the car equipped with the system, but has the effect of warning driver(s) behind also, in a timely way.

Autonomous steering for emergencies is harder to implement, Hermann claims. The complex nature of traffic movements places too much strain on the system – and both Benz and regulators around the world remain agreed that a human pilot should always be in charge where decision-making is concerned.

Hermann does hint, however, that the company is working towards an autonomous steering system, with the foundation stone being its 'Stop&Go Pilot'. This system uses Distronic radar cruise control and cameras to lock onto a car in front and follow it at a discreet interval. It will keep within the marked lines on a road, and maintain that safe braking distance to the car in front, but if the lines disappear, the Benz will then follow the car in front solely.

"That's where autonomous driving will start," Hermann concludes.

Asked whether we could expect to see such technology in a mid-life cycle refresh of the new S-Class, Hermann demurred – which is as close as 'yes' as you'll ever get from an automotive industry executive questioned about future product.

>> Brake Assist Plus with Cross-Traffic Assist to avoid collisions with crossing traffic while reversing.
>> Active Lane Keeping Assist to apply brakes on one side to bring the vehicle back into its lane and avoid colliding with an on-coming car.
>> Adaptive High Beam Assist to configure on the fly the LED-based high-beam headlight system to save drivers of on-coming vehicles from being dazzled.
>> Night View Assist, to alert the driver to the presence of pedestrians and animals near the road at night, while shining a spotlight in the direction of the pedestrian as a warning that the car is approaching.
>> Attention Assist to warn the driver that fatigue is setting in.

If safety is key in the new S-Class, fuel efficiency isn't far behind. One of the principal developments aimed at reducing the S-Class variants' fuel consumption and emissions is the full LED technology, which replaces conventional globes for the headlights, tail lights and interior lighting systems.

Every conventional globe in the car has been replaced by LEDs. There are 56 for the headlights and 35 for the tail lights (not including the four LEDs for the rear fog light). A further 300 LEDs can be found inside, lighting all facets of the interior, among them an ambient lighting array.