Segway PT i2 Getting Started Manual page 67

When your feet are properly positioned on the Mats, all four Rider
Detect sensors depress, allowing the Segway PT to operate normally
in Balance Mode.
If fewer than three Rider Detect sensors are depressed while riding,
the Segway PT reduces the top speed limit regardless of whether
Beginner Setting is enabled or not. Once your feet are properly
positioned again, the Segway PT regains full performance.
If the Segway PT is moved too quickly while in Balance Mode and
none of the Rider Detect Sensors are depressed, the Segway PT will
give the Stick Shake Warning before exiting Balance Mode and
transitioning to Standby Mode.
For additional information on Balance Mode and Standby Mode, see
"Stick Shake Warning" on page 38.
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