VIETA CDV7500GP Owner's Manual page 66

Navigation Operation
If you drive in zig-zags.
If there is a loop or similar
road configuration.
If you are driving on a long,
straight road or a gently
curving road.
If the road has connected
hairpin bends.
If you take a ferry.
If you are on a steep
mountain road with many
height changes.
BR - 66