Collision mitigation and winter a tough mix
Precise sensors meant to keep drivers safe offer little protection against elements
While the auto industry news recently has been overflowing with reports of multiple carmakers racing to get their autonomous vehicles to the streets first, it’s often easy to forget we’ve had several key features of self-driving cars for some time now.
Under the collision mitigation (CM) banner, many vehicles (and not necessarily higher-end units) offer lane-keeping warning or assist, forward (and rearward) collision warning, automatic braking, pedestrian sensing, adaptivecruise control, blind-spot monitoring, rear-view cameras and parallel parking assist.
It’s clear from statistics that these systems can go a long way to improve traffic safety.
But what has also been revealed is how our Canadian winters can turn many of these features into utterly useless technology.
The majority of collision mitigation systems use sensors which detect objects through visual (cameras), imaging (radar) or sound (sonar) methods.
When the sensors are covered in ice, snow or road grime they usually can’t do their jobs.
Some systems will notify the driver via an instrument-panel warning that they’re offline in these conditions, while other less developed units won’t.
The other major factor that leads to these failures is the lack of clear lane markings on our roads (specifically in the case of lane-departure warning or assist systems).
This is not just an issue in rural Canada; a Volvo executive nearly blew his own gasket when trying to demonstrate his company’s latest autonomous prototype on the streets of Manhattan. The vehicle refused to obey any commands to move when it couldn’t ‘see’ any clear lane markings.
Even when there are clear markings on the road, the surfaces of the sensors must be cleaned to keep these safety features working correctly.
Driving on a snowy day means this can pretty much be a fruitless task, but for the rest of the time, keeping a soft cloth and some windshield washer fluid in the vehicle is the best place to start.
Take the time to familiarize yourself with the locations of the various CM sensors on your vehicle.
Most owner’s manuals will contain this information, often along with instructions on how to keep them functional.
Front and rear park-assist sensors are usually located in the bumper covers and will appear as circular dimples, evenly spaced across the width of the covers.
Most front-collision sensors are located behind the grille and are protected from the elements.
They will usually work correctly unless the grille is completely iced over.
Lane-detection sensors or cameras are often found on the underside of exterior mirrors and can quickly collect road grime and slush. The same goes for rear-view cameras.
Never dry-wipe a camera because their lenses can easily be scratched.
Instead, rinse away any grit buildup with washer fluid before wiping dry; keeping some in a spray bottle makes this an easy task.
Some automakers, such as Subaru and Volvo, mount their forwardoriented cameras inside the upper area of the windshield and, as you might suspect, if that area is frosted or iced over, the system likely will not function correctly.
Radar sensors for blind-spot monitoring and cross-traffic detection are usually found mounted inside metal body panels and are generally trouble-free, unless there’s a particularly thick coating of ice or slush on the rear fenders.
In some models, however, these locations have proved problematic because of moisture causing corrosion on electrical connectors.
Getting a thorough under-carriage spray-wash from time to time is a good defence against this.