I have a similar situation.
I work 12 hour shifts on rotation. 4 days of 8am-8pm, 4 days off, 4 days 8pm-8am, 4 days off and repeat.
My ride is 25 minutes (downhill woohoo) to work and 35-40ish minutes (yea uphill
) home.
For my first year I drove to work everyday and only rode for enjoyment on my days off.
Then I got serious about my health and my wallet and decided to make my hobby of cycling really pay off.
I started just a day or two here and there and only on my day shift. Since I have to pay to park only during the day, I had a huge incentive to cut out driving on that shift. Soon enough I started riding in on all my 8am-8pm shifts.
Then my car needed some work and was scheduled to be in the shop during my 4 night shifts. I had limited options. There was no public transit options that would work for me (2 transfers and an hour of time EACH WAY.) Cabs are $20-$30 EACH WAY. Didn't want to bum rides from my girl or my roommates the whole week. So I made the decision to try and ride my way in for my night shifts. Everyone thought I was insane. They told me I would be too tired. They told me it was too dangerous.
Well they were all 100% completely wrong. I crushed that week, and many weeks after that. I ride to work now for a good 75% of my shifts.
You know what? Riding my bike to work has been one of the greatest changes I could have made in my life. I have more money (I am averaging a $40-$50 gas fill up PER MONTH now) and I am in great shape. My days off I can do whatever I want and not worry about making sure I spend X hours trying to stay in shape. I automatically stay in shape just going to and from work.
I still drive to work when the weather is crummy.
So give it a try! Start small and work your way up.
When you are rich and fit you will thank yourself.