Forward Collision Warning (FCW) & Lane Departure Warning (LDW)

Forward Collision Warning (FCW) & Lane Departure Warning (LDW)


This week I’ve been cruising in the new GMC Terrain. And this Terrain is equipped with the most advanced safety features and accident prevention equipment on the market; GM’s forward collision warning (FCW) and lane departure warning (LDW) system. It turns out this simple, relatively inexpensive system makes a big impact.


The simplicity stems from the fact that the entire system utilizes one high-resolution camera to function. The camera is mounted in the windshield, on the right side of the rear-view mirror. The camera constantly takes four different pictures and runs them through algorithms to determine where the lanes are on the road and the relative distance and speed of a vehicle in front of the car. By comparison, most forward collision systems utilize radar on the front of the vehicle – usually the same radar utilized by adaptive cruise control systems.


The hardware’s simplicity leads to the headline of the system: it’s only a $780 option. So, is it worth it?


Short answer, yes. Both the lane departure warning and forward collision assistance work really well. Here are some notes I’ve taken during the last week regarding the system:


  • FCW cuts off the radio and alerts when a driver ahead of you has slowed down to turn. This is really useful when said driver fails to use their blinker.
  • Part of FCW is a “tailgating alert” function. When the Terrain detects I’m following someone close the visual alert goes off.
  • Thanks to the camera’s location at the top of the windshield, the LDW alerts before the driver realizes that the vehicles is veering out of the lane.
  • LDW works even when there are only center road lines (not on snow covered roads when you cannot see the lines).
  • If you utilize the blinker, LDW will not alert when you switch lanes.