I have two little kids (I know that's not three) and public transit or biking (I can fit both on my bike) is great for outings. It turns the journey into an experience itself. Driving with the kids strapped into car seats the whole time is much less fun. I live in a very bikable town within walking distance to light rail, but that was by design. We bought our house by drawing 1/2 mile circles around parks, rail stops, and grocery stores. Bought the first place that intersected all three. I was just thinking recently about how my kids likely be autonomous much earlier. By age 11 or 12 they'll be able to go all around the city on their own.