2010 Volvo XC60: Collision Warning Freak Out
December 07, 2009
Our XC60 is fitted with Volvo's Collision Warning system which flashes a visual alert on the windshield, triggers an audio alarm and will apply the brakes at up to 50 percent of maximum braking power. I had a few false alarms from this system when driving the XC60 over the weekend. One is excusable, the other might not be.
The above photo shows the visual alert which is a line of LEDs built into the dashboard that reflect off the windshield when illuminated. They're much brighter and more obvious than this photo illustrates.
Here are the two scenarios:
The first false happened leaving our office's underground parking garage last week. When approaching the ramp, the system activated in all it's beeping, flashing glory. The ramp to street level is steeply raked enough that it's likely the rear-view-mirror-mounted laser sensor saw the it as an obstacle directly in the line of travel. Because there was no risk, I kept my foot in the throttle and the brakes were never applied -- but the warnings were distracting.
The second situation is less easily forgiven. The system was triggered when driving down a narrow, curving two-lane street at 25 or 30 mph in moderate rain. My guess is that the sensor probably picked up one of the cars parked on the side of this very narrow street and assumed (because the street curves heavily) that it was a car in my lane. In some places on this street parked vehicles actually align directly with the front of cars driving in the lanes. Again, the audible and visual warnings only last a few seconds and the brakes were never applied.
Systems like Collision Warning and City Safety (which can completely halt the XC60 at maximum brake force) are substantial pieces of technology which utilize expensive hardware and demand extensive tuning. Having the sensor range necessary to make them effective probably requires compromises like these in certain situations. Whether those compromises are worth it or not is up to you.
Josh Jacquot, Senior road test editor