Chevrolet 2011 Volt Owner's Manual page 135

The speedometer shows the
vehicle speed in both kilometers
per hour (km/h) and miles per
hour (mph). The DIC menu can
be used to change the units.
See
.
The odometer shows how far the
vehicle has been driven, in either
kilometers or miles.
The trip odometer is within
the Driver Information Center.
See
for more information.