By Motoring Channel Staff - 8/12/2004
Adaptive headlight technology is advancing
rapidly - some new systems will incorporate
satellite navigation to tell the lights when the
car is driving through an urban area, changing
the direction and intensity of the headlights
Over 80 percent of all road traffic accidents occur in darkness
and bad weather, according German automaker Opel which
was a compelling enough reason for its engineers to put their
efforts into developing the next generation of intelligent
The aim is to improve visibility for the driver and so achieve
a significant increase in road safety and driving comfort.
Further motivation for the up-and-coming German brand is
the fact that human eyesight continually deteriorates with
From the age of 45, everyone experiences reduced visual acuity
in poor light conditions and around 25 million drivers
license holders in Germany, or more than half of all the country's
drivers, are older than 40.
Today, Opel (General Motor's German operation) is a leader
in the field of car lighting technology and isn't sitting
on its laurels: in 2003, Opel was the first car manufacturer
to bring dynamic curve lights and the 90-degree cornering
light to the mid-size segment with its Adaptive Forward Lighting
The Vectra and Signum (a Vectra wagon) are still the only
cars to offer Bi-Xenon headlamps, which combine both these
functions in the headlamp assembly.
Engineers at the International Technical Development Center
(ITDC) in Rüsselsheim are currently developing the next-generation
Adaptive Forward Lighting (AFL).
Country light, highway light, city light and bad weather
light are additional functions whose legal basis for installation
in cars is expected to be established from 2007 by a new ECE
norm. Looking towards the future, experts in the field are
conducting the first practical tests of an even more advanced
system at the Opel test center in Dudenhofen, and one that
caters to different driving scenarios, not just rounding corners.
With the next-generation AFL that Opel is working on, the
headlamps' light distribution automatically orients itself
to the prevailing road and visibility conditions. When travelling
quickly in a straight line, for instance on the highway, a
far-reaching beam of light is needed.
The requirements in an urban environment are quite different:
here, the broadest possible blanket of light brings sources
of danger and important signals on the car's periphery into
the driver's field of vision. Thanks to an additional mirror/lens
system, on country roads the road ahead and bends are illuminated
even more consistently and accurately than with today's AFL
And if you thought that was using technology to improve safety,
the developers are even considering linking the light controls
with satellite navigation systems. When provided with this
more exact road information, the system would be able to adapt
to bends or hilltops accurately and in good time.
The bad weather light also ensures that the driver sees more
in rain, snow or fog without, for example, being disturbed
by light reflecting off the road surface. This is achieved
by reducing the strength of the central illuminated area in
favour of two cones of light, which have a middle-distance
range and point towards the edges of the road.
This image shows the difference in
road illumination between standard
lights and adaptive front lights
Opel's lighting technology specialists' main objective is
to achieve the best possible visibility for drivers in all
conditions while eliminating glare for oncoming traffic.
Ingolf Schneider, head of lighting technology development
at the ITDC in Rüsselsheim, quotes further priorities
from the specification book for the next-generation AFL: "To
meet all requirements in terms of aerodynamics, design and
space efficiency, we have to incorporate the additional functions
into the smallest possible space.
"We achieve this by the intelligent multiple-usage and
inter-linking of individual function groups. Moreover, future
multi-functional swivel-headlamps should cost the customer
roughly the same as today's AFL systems," stated Schneider.
The core elements of Opel's next-generation AFL are both
horizontally and vertically swivelling Bi-Xenon headlamp units,
with moveable reflector elements and variable filters mounted
in the path of the beam. In a fraction of a second, electric
step motors adjust these components to adapt accordingly to
the prevailing situation.
The so-called 'actuators' receive their commands continually
from a microcomputer that is integrated into the vehicle's
electronic data network. This assumes control of the AFL system
dependently of sensor-recorded parameters such as speed, front-wheel
lock angle, body tilt, load and ambient light.
The market potential of such high-tech solutions is shown
by the number of orders placed for the current AFL generation.
This year, around 28 percent of Signum buyers in Germany opted
for the steering-linked headlamps. As of August (model year
2005), Opel has offered this high-tech feature in Germany
as part of the comfort package and since then, almost half
(45%) of the Signum customers and nearly a quarter (23%) of
buyers have ordered their car with AFL. In the new Astra for
instance, the AFL curve light is fitted as standard to the
top-shelf version, the 2.0-litre 147kW (200hp) Turbo.
A study by Darmstadt Technical University drew similar conclusions.
By measuring drivers' eye movements while driving, scientists
proved for the first time that curve visibility on night journeys
with steering-linked Xenon headlamps nearly reaches the level
under normal daylight conditions.
More than 50 people were tested with an eye tracking system
based on a highly sensitive infrared video camera. Participants
ranged from the 18-year old holding a fresh driver's license
to professional drivers and experienced seniors up to 68 years
Video imaging and mirroring of two infrared beams aimed at
the pupils showed the following results: Curve visibility
on night journeys with dynamic curve light based on Xenon
technology reaches a visibility of 36 meters, which is almost
the ideal 38 meters in normal daylight conditions. In comparison,
nocturnal visibility with halogen curve lights is only 27
meters, with static halogen headlamps 24 meters.
Like other safety-based technologies in the past that were
once the afforded to only the most prestigious vehicles, such
as ABS, power steering and satellite navigation and tracking,
the technology that powers adaptive front lights will become
cheaper to produce over time and will one day be standard
on almost all cars.
And if regions such as Europe decide to make it illegal for
cars to be sold without adaptive front lights (rumoured to
be slated for 2007) as a safety issue, they could be illuminating
dark roads on even entry-level compact cars much sooner than