Is there a different (lower!) speed limit if you are towing a car? The reason I ask is that I was travelling along the A12 today (dual carriage way with crash barriers = max 70mph for cars). I was coming up for the exit I wanted and was slowing (doing about 60) when a car passed me towing another car. They only had a short length (not even a cars length!!) of yellow nylon rope between them and if the car in front had to stop suddenly I'm sure there would have been an accident. Not only that, but the car being towed had its hazards on and because of the short length of the towrope, it was nearly impossible to see the indicators and brake lights of the car in front, so there was no way for road users behind this pair of daredevils to be warned of what the car in front was going to do. An accident waiting to happen.
It depends on what your towing really. But by law the max is 60mph.
However psychically its possible to go to 70, 80 depending on what your towing. For instance by law the towing vehicle must be 70% of towees weight. Meaning big heavy car, small load and chucks of power and torque.
Thats why 4x4s are the tower's choice, plenty of caravaners use them for their weight alone. The Discovery seems to be the favourite at the minute.
Just another little towing tip...legally you do not need an 'ON TOW' sign, but legally the towed vehicle should display a sign with the towing vehicles registration on it (just like an articulated truck).
in Florida it 65 miles per hour if you are on the highway and less on on the roads and at night. in Texas the maximum towing speed is 7o and 65 at night. so i would tend to think that 65miles per hour is the safest speed. http://4wheelonline.com/Towing/Gooseneck_Trailer_Hitch.199800