Hmm I could only really give personal answers so I will provide this link about the legal consequences - https://oag.parliament.nz/2013/drink-driving/appendix3.htm as to whether these sentences are considered harsh or not, I'm unsure. They're all I know! I can comment on our culture though - we have a nasty drinking/driving history and while things are changing, we lose hundreds of people to driving related incidents each year, in 2017 about 50% of those were drug/alcohol influenced deaths. That article also suggests making the alcohol limit 0 for adults which is the current rule for teenagers which I honestly wouldn't mind. But I rarely drive my car, I live in a small city and I walk everywhere I need to go so this wouldn't impact me in any real way. We do have some stellar ads around drink driving though, etched into our lexicon almost a decade down the line - My parents told me when I was about 16 and heading off for a booze cruise with my friends, how impressed they were that our group always, always, always has a "sober D" and that in their day it would just be a matter of the least drunk driving everyone home. So hopefully we're on the right path culturally.
Interesting! The state I live in seems to have "harsher" penalties in place, but is bottom third in terms of DUI deaths / 100k (source: https://backgroundchecks.org/which-states-have-the-worst-dui-problems.html). Wondering what kind of deeper analysis has been done on this on what really impacts DUIs - definitely looking like at least in the states the highest rates are found in more rural states which do not have walkability like you're describing. That is an AMAZING advert and I want to say thanks for sharing that.