Returning with Uncle and Aunt by car from Lake Hopatcong, and driving along Rt.46 near Rt. 80 in northern New Jersey, I spotted 2 orange lights obviously part of one vehicle, but the space between the two appeared empty -- no craft was visable.

The lights appeared to be vertical, but as we moved south on the highway they became horizontal and the space between them was about 12 of those lights wide, but that area was just dark. However from between the two lights there flew about 8 or more white sparks in a squiggle-type form, extending out what appeared to be 50 to 100 feet.  
I asked my aunt who was in the front passenger seat, to look out her window over her right shoulder and tell me what she saw in the sky.  She spotted it and said "What the heck is that?" We both watched this display for a couple minutes, commenting to each other on what we saw, and wondering what it could be. 
My uncle was all curious but could not stop the car as there was considerable traffic and no shoulder on which to park.   We discounted any commercial display or advertising -- although its altitude appeared to be less than 2000 feet, and it surely was not some small plane or helicopter.  After a few minutes we had gotten so far from it we could no longer see it.   
A few years ago I came upon a paper-back book being sold on a super-market revolving display and showing pictures and drawings of various sightings, in which was a diagram of exactly what we saw and the date it appeared -- but the darn book was $23 bucks and I didn't feel it was worth buying.  But I've kicked myself many times for not buying it.  My uncle and aunt are gone -- but my memory of that sighting will never leave me.
Witness indicates that the date of the incident is approximate.  PD