white/yellowish lights shaped like a bulldozer track moving in a counterclockwise direction.

My wife, 2 daughters and I were driving south on Interstate 93 late November 1977 about 8 to 10 miles south of the New Hampton, NH exit.  It was about 22:30 in the evening, very clear and cool (maybe 45 degrees F)outside.  We were traveling about 75mph, without any other vehicles around.  I was driving the vehicle and out of nowhere there appeared this UFO on the drivers side of the car.  It was about 100 to 150 feet above the ground moving in the southern direction with us at the same rate of speed.  The only visable feature of this UFO was a band of lights moving in the counterclockwise direction.  The lights reminded me of a track used on heavy equipment like a bulldozer track.  The individual foot pads (like on a track) were lite very bright (kinda white/yellow color) just like the color of a light bulb.  There was even spaces between each light just like the spaces between the pads on a bulldozer track.  The rate of movement on the lights was about 50 t! o 60 RPM.  As I stated before we could not see any shape at all besides these lights, nothing.  The size of this object was about 10 times the size of our vehicle (1977 Monty Carlo).  The UFO stayed with us for 1 to 2 minutes and disappeared as quickly as it appeared.  We did not see it arrive or leave, it just appeared and then disappeared.
Witness indicates that the date of the sighting is approximate.  PD