My husband was born and raised in the next town over(and we still live in town) and every teenager had a car. You couldn't get anywhere without one. Cars were easily had, much cheaper and easily worked on. My husband can't think of one friend that didn't have a car in those days. Perhaps some bigger or financially strapped families had kids share one but at least here in Belchertown it was more common for teens to have their own car than not. We're talking about towns that in the 70's (and even today truthfully) that do not have stores, restaurants etc on every corner. Belchertown didn't even have a grocery store of its own until the 2000's LOL
You are correct in saying that in the '70's you couldn't go anywhere without a car in that area. However, that meant a lot of students didn't go anywhere! That was true for all 5 campuses, I believe, although there was generally a frat party or two on weekends at Amherst College. Even wealthy college students didn't have cars. (Cars actually weren't allowed freshman year on my campus.) I knew one student in my class who had one, but she was a day student from Granby with a single working father. I knew twins in the class after me who had a car (a Pinto, lol), but they were able to split the price and upkeep; they were the only ones in my entire dorm to own a car! This was pretty typical.... Students were in the area to study, not to party (the dorm had only one TV, and most of the time it was off, for gosh sake). My friend from Granby partied in high school, but it was a whole different scene when she got to college.
So, although many high school students in the area might have had cars, this was not true of college students.
I even had professors who didn't have cars (professors were required to live nearby, incidentally).
And, as I mentioned in my post above, the nearest big mall was in Connecticut (Enfield). The current busy drag through Hadley was mostly fields: certainly not the mix of major stores and hotels there now. There were not a whole lot of restaurants, even. I remember the Rusty Scupper, but that was it! A restaurant meal was a big treat.
There was a free bus that linked the five colleges.
I didn't know of a single person in my high school, either, who had a car. Except my older brother, who worked 30+ hours per week, which allowed him to pay for one. Even at grad school, students didn't have cars: I did grad school at a wealthy university and I was the only one I knew who had one, and I worked for 2 years before grad school so I had some savings. (Tires weren't good in those days, so it frequently had flats.)
My parents could never have afforded a car for any of their offspring, even though my father had a comfortable salary.
Something nasty could have gone down at an Amherst frat party...... If anything, frat parties in general were worse then than they are now (since then, frats have been abolished at Amherst IIRC). At Amherst, frat parties were reputed to be ankle-deep in beer: a young woman could easily have been assaulted while in a stupor.
What do you think the possibility is that the perp(s) in this case could have been a local high school student(s)?