Some interesting points being raised throughout the thread and mirrors some of the thinking that I've been mulling over in the last year or so. For us as a family, a car is an essential for a number of reasons, not least of which is the fact that my family live in the SW of England and by far and away the cheapest way to get there with my family, from Germany, is to drive. My wife also uses the car for work as there just isn't a practical alternative, public transport is just sadly too intermittent to get her there and back on time. We've never had to use a car for school runs though, with the junior school a 100m from our door and now eldest daughter has moved on, her school is 5km away, but she has a free bus pass and two buses whisk her to school every morning.
That all said, we have been mulling over ways to cut our already low car usage even more. Whilst small shopping errands have always been done by bike, it's not been practical to do a weekly family shop by bike, the nearest large shops are 4 km away which is too far to walk with a weeks shopping and no busses run there. In Germany we also don't have shopping home delivery services, so car it was.
I did weigh up a number of options like cargo bikes, but we had no good storage options for a big heavy cargo bike, so I settled on a trailer from Croozer. It's been absolutely brilliant, we have two bike attachment mounts on some ancient old town bikes that we use as general run around bikes and we use it for running all manner of errands. The trailer cost €300, but that's it, in 10 months I've not spent another penny on either the bikes or trailer. It gets used weekly for all kinds of errands and easily swallows a week's family shopping along with the occasional cheeky crate of beer. Just this morning it was -1 when I set off with a trailer full of paper and glass recycling, that done it was off to the supermarket for a weeks family shopping.