I've been doing a 30mins each way school run for the last um 5 years. It really isn't ideal to say the least.
I don't think it is fair (or tenable) on younger siblings doing it, and I couldn't do it twice a day, 5 days a week myself (2 hrs+ in the car) so I have a full time nanny. This means that we can share school runs, and whoever doesn't do the morning school run stays at home with the younger ones.
If I didn't have the school runs from hell I'd probably have more part-time help. So it is expensive from that point of view!
Environmentally it is also a disaster, obviously
However I wouldn't say that 30mins in the car 2ce a day is terrible for the ones on the school journey - we get a lot of talking and singing and what have you done in the car (including ORT reading!) so by the time they are home they just tumble out and run off to play. It is just a killer on the person doing the return trips! So if you can do a car pool with other local parents, it becomes much more manageable.
Finally, whoever said that it can end up being 3x a day or more at the ends of term is absolutely right. Judo displays, ballet displays, parents evenings, plays - there are a lot of those sort of things.
So basically - if you have a decent option nearby, then try that first. If you don't, then move house. If you have no other decent option, and can't move house (like me) then be prepared for some seriously dull travelling.