Night hawks

At the Frankfurt motor show the spotlight is on road safety, with BMW and Mercedes both showcasing systems to help drivers see and avoid hazards in the dark. Dan Thisdell reports.

Motor industry players from around the world are heading for Frankfurt next  week to sell cars, rub shoulders and survey the competition. And they won’t be disappointed by Europe’s biggest motor show. The drapery will come off no fewer than 122 new car models – including 80 world premières – and component suppliers are promising over 100 innovations. For many, Frankfurt will also offer a first look at some of the Chinese brands hoping to break into the European market.

The biennial showcase should put a spring of optimism in the steps of European motor moguls whose outlooks, and bottom lines, have been dented by the weak dollar and strong oil prices.

But engineers, marketing gurus and road safety campaigners will be taking a careful look at a new technology that could help to save some of the 9,000 pedestrians and cyclists killed yearly by cars on Europe’s roads. Another 200,000 injuries result from accidents, with the hours of darkness being the most dangerous. Few will challenge the argument that the time is right for drivers to benefit from systems such as military-style night vision technology.

BMW and Mercedes-Benz will both show infrared night vision systems at Frankfurt, on their top-of-the-line 7 Series and S Class saloons. The great commercial rivalry between these two companies is reflected in the differences between the technologies they have chosen.

BMW’s approach uses Far Infrared technology (FIR), a passive system that has an infrared camera mounted in the front bumper to see some 300m up the road. A black and white image is shown on a screen on the dashboard, with warm objects showing bright. BMW claims the system, made by Swedish supplier Autoliv, is ideal for highlighting pedestrians, cyclists or animals beyond the reach of high-beam headlamps.

Mercedes-Benz has opted for a different approach. Its Near Infrared (NIR) night view assist system, supplied by Automotive Lighting, features infrared searchlights in the headlamp housings. These illuminate the road ahead to a range roughly that of a car’s high beams. An infrared camera inside the windscreen detects the reflected light, which is electronically translated into a clear greyscale image displayed on a screen in the instrument panel. NIR technology shows a driver not only hazards like pedestrians, but also the course of the road.

Because IR light does not dazzle drivers of oncoming cars, the system helps maintain a driver’s perception of the road even when high beams cannot be used. Drivers with night view assist may also have a better view of the road at moments when they are dazzled by light from oncoming cars. According to Mercedes, collisions at night often result from drivers losing control of their vehicles because they were unable to recognise the course of the road and slow down in time, with more than half these vehicles leaving the road or hitting oncoming traffic.

The Mercedes system would appear to be superior in that it helps drivers avoid accidents beyond colliding with a pedestrian. BMW spokesman Frank Schloeder readily concedes that a driver comparing both systems will be immediately impressed by the clarity of the scene viewed through the Mercedes NIR screen. But, he said, in this case more detail is not necessarily better. BMW’s approach is based on wanting to warn drivers of a hazard, not riskdistracting them by replacing their ordinary vision through the windscreen.

Indeed, BMW sees little use for the system in city driving, where there is light from streetlamps and other vehicles. Instead, Schloeder believes FIR is the right way for BMW to go for several reasons. The system ‘sees’ about 300m. This is beyond the range of high beam headlamps and twice as far as was achieved by Mercedes’ NIR systems in a University of Michigan test, cited by BMW. FIR also has fewer components, and is not itself dazzled by the lights of oncoming traffic, though Mercedes claims to have minimised this problem.

Other night vision systems will also be on display. Leading French vehicle electronics maker Valeo plans to unveil such a system, though it won’t yet release details, while German supplier Siemens VDO is working on both NIR and FIR systems and will be demonstrating the technology at Frankfurt as part of its focus on driver assistance systems.

For all the inevitable European interest in BMW and Mercedes’ market-ready cars, the two manufacturers are picking up a baton already put down by the industry’s biggest player, General Motors. In 2000 GM’s US luxury brand, Cadillac, offered an FIR system with head-up display as an option on its Deville saloon at a cost of about $2,000 (£1,000). Internet postings suggest drivers in northern states liked the idea of obtaining a warning that they might be heading for a collision with a deer, but the cost of the system may have been too great. According to GM, customers were reluctant to pay for technology that is difficult to appreciate without direct experience.

So the option was dropped late last year. GM has also conceded that night vision’s lukewarm reception may have owed much to a failure to consider the needs of Cadillac’s target audience. While the technology is most useful to drivers on dark rural roads, the typical Cadillac owner is a wealthy urbanite.

Whether BMW and Mercedes are heading down the same path to market disappointment remains to be seen. BMW’s night vision system will cost a fairly pricey £1,330 in Germany.

However, five years on from its introduction by GM, BMW is claiming some critical improvements which may be more effective in persuading buyers to part with their cash.

According to Schloeder, BMW has introduced lots of electronic image enhancement to improve contrast and picture stability along with automatic zoom and panning functions that offer a better picture at speed or on bends.

The system also uses a dash-mounted screen rather than a head-up display because a moving image in the driver’s main field of vision proved distracting.

Meanwhile, a £5.5m European Union-supported project known as SAVE-U (Sensors and system Architecture for VulnerablE road Users protection) is working to develop a more advanced system combining stereoscopic infrared thermal imaging with radar to detect and identify objects in the road and plot their course. The system will alert drivers to, say, a pedestrian in the road by highlighting its image on a screen with a red box and activating the brakes automatically if necessary. A spokesman for Siemens VDO, which is working on the sensors for SAVE-U, said that to be reliable a pedestrian detection system needed lots of computing power but the company was optimistic that good results would be achieved.

Honda has already opened the door to this next generation of night vision technology. Last summer the company introduced the world’s first intelligent FIR system in Japan only. This uses two infrared sensors to identify pedestrians moving across a car’s path, giving drivers a visual warning on a head-up display.

But ultimately only the market and road accident statistics will tell if the BMW, Mercedes or Honda systems are adequate, or if it will ultimately take SAVE-U or an even more advanced concept to bring effective night vision from the battlefield to the highway.