Street lights in residential areas could be switched off at night in a bid to save money.
Between 12.30am and 5.30am 10,000 street lights would plunge into darkness in the quieter areas of West Sussex if the proposals were to get the go ahead.
The county council said concerns about increases in crime and a rise in the number of traffic accidents have also been considered, but no evidence has yet been found which backs up these fears.
The council has operated a part night lighting policy since the 1970s and already has 30,000 part night lights in residential roads where there are fewer people on the streets and limited car movements in the early hours of the morning.
The proposal is now in the discussion phase with local councils.
Main roads in urban areas will remain lit although the majority of street lights are already dimmed by 50% cent after midnight to save energy.
Town centres will not be affected by the proposal at all and will remain lit throughout the hours of darkness.