Garmin GPS IIplus Owner's Manual page 64

Reference
Fig. 58
58
Using the Highway Page
+
The GPS II ' s Highway Page (Fig. 58 and p. 59) also provides graphic steering
guidance to a destination waypoint, with a greater emphasis on the straight-line
desired course and the distance and direction you are off course. As you head toward
your destination, the middle of the screen provides visual guidance to your waypoint
on a moving graphic "highway."
Your present position is represented by the diamond in the center of the course
deviation scale. The line down the middle of the highway represents your desired
track. As you navigate toward a waypoint, the highway will actually move—indicat-
ing the direction you're off course—relative to the position diamond on the CDI
scale. To stay on course, simply move toward the center of the highway.
If you do get off the desired course by more than 1/5th of the selected CDI
range, the exact distance you are off course will be displayed where the CDI scale
setting normally appears. If you get too far off course (the highway has disappeared),
a message box will appear to indicate what course to steer to get back on course.
(For information on how to set this scale, see p. 78.) As you approach a waypoint, a
horizontal "finish line" will move toward the bottom of the highway. When the finish
line reaches the CDI scale, you've arrived at your destination.