How to operate a wheelchair safely outdoors<br>Stay on even surfaces. Uneven surfaces can make any wheelchair get off balance. Even when someone is pushing a wheelchair, an uneven surface can cause harm.
An uneven surface will harm anyone pushing a wheelchair.
( z1 harm :ARG0 ( z2 surface :ARG1-of ( z3 even :polarity - ) ) :ARG1 ( z4 anyone :ARG0-of ( z5 push :ARG1 ( z6 wheelchair ) ) ) )