Practically speaking (from personal observation), it would be pretty hard for a family to get by without a family car, in a car-centric place like Boise, Idaho. There are destinations that the entire group travels to, across town or out of town. There are occasional heavy or bulky loads that have to be transported. Even the most charitable friend might grow tired of loaning you his pickup truck, if it happened every couple weeks or so.
For most of us, myself included, "car-free" isn't practical, but "car-lite" is something we can do.
Particularly in the summer, I go for weeks at a time without getting into a car, either as driver or passenger. But inevitably, I'll need to drive across town with the wife and kids (who are bike-averse). Or haul a load of Venturer Scouts to Donnelly. Or I'll have to get some bags of concrete mix or a stack of 2-by-4s at Lowes... and the car comes in handy. (Sometimes I amaze myself at the loads I can transport on my BOB trailer. I've carried everything from tomato plants, to bakery-outlet bread, to 2-liter soda bottles and ice cream, to shovels and rakes, to 8-foot sections of crown molding. But now and then, it just ain't gonna happen.)
A student, on the other hand, might have an easier time. Biggest load - might be all those books. The most distant destination might be the convenience store (with fake ID in hand). And - it's a significant hassle and expense to operate AND PARK an automobile on campus.
Boise State University just made it easier for students to go "car-lite." Starting this fall, students (over 18 with good driving records) can join ZIPCAR. Zipcar is a cooperative of folks who join up and have a fleet of cars available for rent, either by the hour ($8) or the day ($66). Gas and insurance and 180 free miles are included. (I'm assuming that's for the day - that would be some serious driving - even by a student - to rack up 180 miles in an hour!)
According to Wikipedia, Zipcar is "a for-profit, membership-based carsharing company providing automobile rental to its members, billable by the hour or day. ... [It is] the world's largest car-sharing service, sharing 6,000 vehicles among 275,000 drivers in 49 U.S. cities, Vancouver, Toronto, and London..."
Interesting concept. I hope it works out for Bronco Nation. (For non-students, on the website Boise is listed as a "Zipcar city," but it says "There aren't any Zipcars at Boise... Check back soon.")