16 round trip? 8 miles one way? Take the bicycle! ZERO fuel.
7 or 8 years ago, I lived 10 miles from work and I rode my bicycle as often as I could! Took me 45 minutes each way. But, I was lucky in that my office building at that time had a fitness center with excellent shower facilities. I had a child seat on my bicycle, and I just put my office clothes in a backpack and tossed the backpack in the child seat. No sweaty clothes, rainproof, and ZERO fuel costs! I loved it!
My boss lived 7 miles away, and he rode a bicycle too.
Now, I'm 14 miles away and no sidewalk or bike lane on 6 or 7 of those miles, making it just a bit too much of a challenge.
My son commutes on his XR650L, getting ~50mpg.