ASC Regulation tl;dr
The occupant space by regs is defined by an 835 mm arc pivoting about a designated point. Nothing can be within this arc with the exception of the steering wheel, mirrors, and seats. When occupants are seated normally, with safety-belts and helmets on, no part of the occupant nor the full free range of motion of the occupant's head (with helmet) may extend beyond the occupant cell (defined as roll cage + structural chassis). For ASC there is no minimum amount of space between the occupant's helmet and the extent of the occupant cell. For WSC only, no point of any occupant’s helmet may lie within 50 mm of the extents of the occupant cell.
By regulation, the minimum occupant cell size is based on a 50th percentile male (not including helmet space). Thus, as a team we have a say over who will be able to fit inside our vehicle.
Our Internal Goals for Sizing
We would like to accommodate as many different sized people as possible within our vehicle as we are shipping ourselves as a consumer-oriented passenger vehicle. The industry standard in automotive design is to comfortably accommodate 90 percent of the population ranging from 5th percentile female to a 95th percentile male (FSAE Rules95th_2016.pdf; think bell-curve distribution of people ranging from small woman to large man). With that being said, we also need to design a competitive vehicle for competition, so comfort will be compromised (to some extent) to optimize vehicle efficiency.
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