It's been almost two years since I've had my 2014 Volt, but I keep learning new things about it. Recently, I did a comparison between driving in L vs D and discovered that driving in D was slightly more efficient for me. This was attributed to the fact that gliding was probably more efficient than doing more regen with L. My previous car was a Prius and since pulse and glide usually produces the most efficiency, I was thinking that using sport mode to get up to speed quickly and gliding until the next stop could increase my efficiency. So, after a couple of comparisons, it seems that sport mode was about the same or slightly more efficient than normal mode. One thing that surprised me, however, is the fact that driving in L in sport mode seemed to be about as efficient or more efficient than D. This goes counter to my previous trial where D was more efficient than L. However, with the small sample size and road construction and changing weather, its hard to be absolutely certain. I'm surprised that no one else has made a more quantitative study on this.