Honda 1990 Accord Sedan Owner's Manual page 76

Parking with a Trailer
Whenever parking your car on an incline with a trailer attach-
ed, place and seat chocks at each wheel of the car and trailer.
This is in addition to the normal parking preparations of firmly
applying the parking brake and placing the transmission in first
or reverse (manual transmission) or P (automatic transmis-
sion).
CAUTION: Parking on an incline is not recommended and
should be done only if it cannot be avoided. Follow all precau-
tions mentioned above and turn the wheels to point towards a
curb if facing downhill, away from a curb if facing uphill. When
leaving an inclined parking place, move the car slightly to
unseat the chocks. Then while keeping the foot brakes firmly
applied, have an assistant remove the chocks.