TOYOTA 2011 Avalon - Manual (Page 238)

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2-5. Driving information
AVALON_U (OM41428U)
Trailer towing
Toyota does not recommend towing a trailer with your vehicle.
Toyota also does not recommend the installation of a tow hitch or
the use of a tow hitch carrier for a wheelchair, scooter, bicycle, etc.
Your Toyota is not designed for trailer towing or for the use of tow
hitch mounted carriers.