After driving this road in Palos Verdes, California over one hundred times it hit me, this would look really cool at night. So I climbed to the top of this hill and waited for the "perfect traffic." It's really hard to time it so one car is going in each direction and both cover all of the turns within the longest exposure of the five.
The huge glow in the upper left is from the city of San Pedro. That house on the top of the hill has one heck of a view.