I'll admit I've got a small diesel car. I get better fuel economy, I personally find diesels nicer to drive and I'm (just) doing the mileage where it makes financial sense too. It's as "green" as a normal car with an internal combustion engine gets and it has Stop/Start so it doesn't sit in traffic queues pumping out any emissions - the only emissions are when it's moving. It is properly maintained, it spends most of it's life on A roads and motorways and it doesn't ever kick out black clouds of soot when it's driven. And I drop Mrs ND at work / pick her up on a night so I'm also car sharing.
I would dearly love to get a ZEV, but that means going electric and that can't happen with current infrastructure: I live in a terrace house with on street parking so no drive / garage to park it in while it's charging. I could run an extension lead out of the letterbox and across the pavement, but I'm fairly sure that either someone would trip over it and sue me, or I'd come out in the morning and find it had been unplugged before it was charged. And that's assuming I can get parked outside my own house and not 100yds up the street.
There is virtually nowhere in the town where I work to charge an EV either. The only place I can think of is a supermarket a mile or so away from work which has two charging points and a two hour limit on parking...
I've tried public transport, but even with the congestion on the roads, using the car takes at least 30 minutes less and depending on the time of day that I finish this can be considerably more. The cost is also comparable with running a car and I've been the lucky recipient of a written warning for time keeping from my employers last time I used public transport for any length of time as it was so unreliable (I ended up going for the train before the train before the train I needed to catch on a morning and still failed to get to work on time at least a couple of times a month). So that's a no for regular commuting.
So, happy to take a more environmentally friendly choice when there is one that works for me. Until then It's the car.
PS - the car is only used rarely outside of commuting. This weekend it was parked up on Friday night and won't turn a wheel until Monday morning. Weekends we walk / cycle or use public transport whenever we can.