Driving from NH to PA many times, I've gone down the parkways every time towing my covered trailer with my Cobra in it. I've had many locals "yell" at me, so I looked up the law. It is trailers over a certain height (which mine isn't) and commercial trailers (which I am not). That cop was mis-informed about the trailer on parkways law.
Quick google search:
"In New York, trailers, especially those attached to commercial vehicles like tractor-trailers, are generally prohibited on parkways. This is due to low bridge clearances and the design of parkways, which were intended for passenger vehicles. Commercial vehicles, including trucks and tractor-trailers, often strike these low bridges, causing accidents and delays.
Specifics:
Parkway Restrictions:
Many parkways in New York have restrictions against commercial vehicles, including trailers.
Low Bridges:
Some parkway bridges have clearances as low as 6'11", making them hazardous for taller vehicles.
Potential Consequences:
Violating parkway restrictions can lead to fines, points on your license, accidents, and damage to vehicles and infrastructure.
Examples of Restricted Parkways:
Some parkways with restrictions include the Taconic State Parkway, Bear Mountain Parkway, Saw Mill River Parkway, Bronx River Parkway, Cross County Parkway, Hutchinson River Parkway, Sprain Brook Parkway, Long Mountain Parkway, Palisades Interstate Parkway, and Lake Welch Parkway, according to
www.speedlaw.net. "