24 Fleet Maintenance | March 2018
overcome maintenance neglect in
these key areas.
“If your tires are bald and your brakes
are worn, the safety system is going to
utilize these as best it can, but it’s not
going to work optimally,” Andersky says.
He adds that it’s important to keep in
mind many safety systems interact with
and build on each other.
“If the ABS system has a fault in it,
that’s going to take out the stability
system,” he says. “And if the stability
system is not functional, the collision
mitigation technology is likely not to
be functional either. Keeping your ABS
system, your brakes and your tires in
good shape takes care of everything else.”
It is also a good idea to keep cameras
and radar sensors clean and free from
bugs, snow, ice, mud or any other type
of buildup that might interfere with
normal operation.
Some systems, such as Lytx’s in-cab
camera systems, are self-sustaining to
the point that they even keep themselves
up-to-date with the latest available
soft ware.
“Upkeep largely comes from overthe
air soft ware updates and bug fi xes,”
says Lytx’s Lisk. “Th ey’re connected by
cellular. Every day they’re connecting
back to our servers and getting soft ware
updates, bug fi xes, sending data to us,
all back and forth.”
He goes on to say that in the event of
a unit failure, replacement is a simple
plug-and-play process.
“We’ll send the fl eet a replacement
and, essentially, they just plug that in.
It’s just a straight swap-out,” Lisk says.
While most safety systems are relatively
durable, they are not completely
impervious to damage from accidents.
Even an event as minor as a driver
pulling forward too far and hitting
a parking pylon with the radar can
cause the sensor to malfunction or
stop working. Fortunately, in situations
such as these, technicians should
be able to make the repairs without
special training.
But Andersky warns not to assume a
sensor is faulty unless physical damage
is evident.
“Don’t run off and replace the radar,”
he says. “Check the wiring going back
through the harness to see if there’s a
spot that’s worn through or something.”
In the event of a more severe collision
where additional components need to be
replaced, more complicated repairs such
as system calibration may be required.
“If you do front end work on a vehicle
equipped with a stability system, like a
front end alignment, you do have to go
There’s a sensor for that
One thing that all safety systems have in common is that they
rely on sensors to provide them with the raw data needed
to calculate risks and alert the driver of an impending event.
Here are some of those sensors and how they work.
• Ultrasonic sensors - Send out audio waves at a specific
frequency and wait for the waves
to bounce back to determine
how far the vehicle is away from
another object. These are most
commonly used in forward and
reverse proximity sensors.
• Radar sensors - Send out electromagnetic
waves (rather than the
audio waves used by ultrasonic
sensors) to determine how far an
object is away and how quickly it
is approaching. Radar sensors are
used in some blind spot detection
and forward collision detection
and mitigation applications.
• LiDAR (Light Detection and
Ranging) - A more advanced
form of radar, LiDAR scans the
environment using a non-harmful
invisible laser beam to provide
a three-dimensional view of the
surrounding area. When combined
with camera data, LiDAR
can be used to detect what type
of object the vehicle is approaching
(vehicle, pedestrian, etc.).
• Cameras - Used in some forward
collision detection and mitigation
applications. Also used for maneuverability
at low speeds (forward,
rear and 360-degree cameras),
to monitor driver awareness and
to record unexpected incidents.
» Infrared - Creates an image
using infrared radiation
instead of light like a typical
camera. Used to help some
vehicles “see” in the dark.
» Machine vision - Analyzes
and interprets images from
camera sensors to determine
risks. Used in some lane keep
assist, blind spot monitoring
and collision detection
and mitigation systems.
• GPS - Pinpoints the vehicle’s location
and speed by determining
distance from global satellites.
• Accelerometer - Measures
acceleration and deceleration
in a vehicle. Used to determine
sudden unexpected
maneuvers or collisions.
• Connection to vehicle CANbus
- Allows certain systems to access
vehicle information such as
steering, accelerator and brake
input, vehicle speed, etc. Can be
used to determine driver inputs
during an unexpected maneuver
or an accident and later used to
determine the cause of the event.
VehicleServicePros.com/20977932
» Drivers are given visual and
audible warnings when the system
detects an impending collision.
Photo courtesy of Volvo Trucks North America
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