If the night riding makes you uncomfortable or is just plain unsafe in your area, just ride the morning commute and hitch a bus or ride home with a buddy if possible.
There have been numerous (if you believe me!) studies that have shown that even short periods of exercise, especially in the morning, have substantial benefit to fitness, sleep regularity and overall health. If ride sharing is not possible and the darkness is evil hit the trainer for 20 minutes before breakfast, shower eat and go. This would take no less time that your commute anyway.
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"I love fools’ experiments. I am always making them." - Darwin