Pioneer AVIC-8200NEX Operating Manual page 82

Appendix
 If there is a parallel road.
 If there is another road very nearby, such as in the case of an
elevated freeway.
 If you take a recently opened road that is not on the map.
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 If you drive in zigzags.

If the road has a series of hairpin bends.
 If there is a loop or similar road configuration.
 If you take a ferry.
 If you are driving on a long, straight road or a gently curving
road.

If you are on a steep mountain road with many height
changes.