Ok, what happens at Night? It gets Dark. So what do you need to be able to see, Lights!
You are getting interference from the Lighting. If your equipment is very close to a Light Pole, try moving it further away. Otherwise a bad Transformer in the light pole can cause interference and even glitching of the cars.
Also, are you using Coaxial Cable, or Shielded Wire?
Normally Shielded wire only has the shield connected at one end. If you ground both ends, it will be ineffective.