why 3 doors?

[HO455]

I believe both of those stories can be discounted. Photos in this thread linked below show a four door suburban was planned in 1964 and by 1965 the 4th door had been dropped in favor of the 3 door version.

The National Highway Safety Act was not passed into law until 1966 and it wasn't until 1968 that those laws took effect. Second link.

Stand alone roll over tests are really a thing they are tied into the collision avoidance test. Those tests didn't begin until the 21st century. The 3rd link describes the current testing done and gives a history of the program.

http://67-72chevytrucks.com/vboard/f...splay.php?f=38

https://autouniversum.wordpress.com/...ety-standards/

https://www.caranddriver.com/feature...ngs-feature-3/

And as far as a school district charting the course of a new vehicle, I firmly believe that GM wouldn't have taken orders or even recommendations from a mere school district. They were General Motors. Back then they barely obeyed the laws the government passed down to them. Of course GM would of made a special bus version for a school if the school district was willing to pony up the extra costs.

I truly believe the decision was based on money, and money alone.