Originally Posted by P.C.

My latest car has several of the features that comprise the suite of eight I-Activesense features available in the Mazda 6, including the radar cruise control, and I like it because while it doesn't lull me into any false sense of security, it is nice nevertheless to feel that the car has your back. Just set the cruise for, say, 65, and as you drive down the interstate you maintain that speed unless and until you come up behind a car in your lane that is driving more slowly. In that case, your car slows down, applying the brakes lightly if necessary, and maintains a gap (which I can adjust in size) between the vehicles. If the passing lane is clear, I can pull out, and the radar, recognizing the clear lane, allows the car to accelerate back to the set speed.

It is a good system, but has its limitations: Because of the existence of two-lane roads with oncoming traffic, the cone of radar detection is relatively narrow from a left-to-right perspective (to keep the system from crapping its pants if it spots an oncoming car being driven normally in its own lane). If a car is a moderate distance in front of you, and can be picked up by the radar while both cars are on a straight section of road, it is possible that if the car in front of you enters a decently sharp curve, the radar will lose track of the preceding car, and the cruise system will prompt acceleration if you were traveling below the set speed before you entered the curve. The acceleration is not strong and can be easily countered by the driver, but it does point out a limitation of the system. A similar limitation can be noted if you are driving on a road with a lot of up and down pitching (driving on a road with a lot of short but steep hills). If the nose of the radar-equipped car pitches up or down too much, the radar will lose track of the preceding car and some acceleration can occur. Again, nothing wild, but it can happen. Ford goes to great pains to explain these shortcomings in the owner's manual, and the driver can elect not to use the radar control, controlling the speed manually, or can set the cruise control to a non-radar setting, and use the old-school type of cruise control that will attempt to maintain a set speed unless defeated by the driver.

Interesting system, which will no doubt undergo more refinement as the years progress.