Welcome to the board!!! This is a great question. By big you could mean both round or tall? I imagine all the Disney rides are designed so that 90% of humans can ride, just like cars. Meaning that 5% on the top and bottom ends will have difficulty riding, if at all. While I am certainly overweight, if not obese, I do not have too many problems except for the safety bars sometimes since my fat is mostly in my abdomen and not my posterior. Like April (Stitch) I too have problems with the teacups, but I squeeze in there somehow.
Originally Posted by PA. Chris
Here is some specific info:
Roller Coaster Design Standards
The American Society for Testing and Materials (ASTM) has a committee that deals specifically with amusement rides and devices. Standard F 1159 - 97a develops design procedures in accordance with passenger weights. The weight assigned to an adult passenger for design purposes, shall be 170 lb (77kg) or 12 lb/in. (5.4 kg/25.4 mm) of hip width at the seat, whichever is the greater amount. The weight assigned to a 12-year-old child passenger for design purposes shall be 90 lb (41kg) or 9 lb/in. (4.1 kg/25.4 mm) of hip width at the seat, which ever is the greater amount.
The Society of Automotive Engineers (SAE) has published a description of the physical dimensions of a human. Standard SAE J833 specifies the physical and body pivot dimensions for small, medium, and large humans. A small human represents the 5th percentile female meaning that only 5% of the female population are smaller than the dimensions listed. A medium human represents the halfway position between the small and large humans. Large humans represent the 95th percentile male. Only 5% of the male population are larger than the dimensions given. For the purpose of our project, we will be designing our harness and restraining mechanisms in accordance with a large human. If a height restriction is required, it will be determined at a later date. The typical dimensions we will be concerned with are listed in Table 1.
Table 1: Human Physical Dimensions (SAE, 130)
ASTM standard F 1159 – 97 also sets standards concerning passenger carrying devices. The seating must be designed "to provide adequate support padding and containment for the passenger’s body during operation, and to be consistent with the design intent of the ride." Restraining mechanisms may be used when appropriate; however, the devices may not be limited to the height, speed, and forces on passengers. Passenger clearance is another standard. Design clearance is a standard that ensures safety against passengers coming into contact with other passengers or with objects that could cause injury during operation of a ride or device. This ASTM standard also states that a design will provide sufficient braking capacity to satisfy the designer’s recommended operation parameters. A block system must be implemented for those rides and devices where, by the ride design, it is necessary to prevent independent passenger carrying units from occupying the same area or block of the ride.