From personal experience, I find riding at night slightly safer. Let me first say that I have a number of lights on my bike.

Rear blinkie, helmet blinkie, headlight, and front blinkies. Also have rear facing blinkies in the ends of my drop bars.

My experience is that during the day cars can see you and are unafraid to buzz you, relying on their "awesome" driving skills to come within inches of you without hitting you.

At night, when they cannot clearly see your outline, rather just a bunch of lights, so they give you more room.

Just my opinion.