In scope: occupant cell space requirements, seat geometry regulations, forward and sidewards vision, rear vision, structural chassis clearance from occupants

Out of scope: occupant cell safety (FEA), seat belt regulations, egress, ventilation, crush zone

ASC/FSGP 2018 Regulations (Rev C – Released Jul 1, 2018)

9.5 Visibility

9.5.A Eye Height

In the normal driving position with a fully laden solar car, all occupant’s eyes must be at least 700 mm above the ground.

9.5.B Forward and Sideward Vision

9.5.B.1 From the normal driving position, the driver must be able to see at all times, without artificial assistance, points at the following locations:

(1) A point on the ground 8 m in front of the solar car

(2) A point 6.4 m above the ground and 12.2 m ahead of the leading edge of the car. (Will be inspected with a pole positioned 3 m ahead of the car)

(3) A full 100° to either side of center

9.5.B.2 The driver will be required to identify 75 mm high letters at a distance of 3 m from the front of the solar car, through any of the required viewing angles.

9.5.B.3 The driver will be required to identify 50 mm high letters at a distance of 3 m from the side of the solar car, through any of the required viewing angles.

9.5.B.4 Some elements of the roll cage may obstruct a portion of the forward vision. However, this view must be essentially unobstructed as much as is reasonably possible by the solar car structure.

9.5.E Rear Vision

9.5.E.1 All solar cars must be equipped with a rear-view system that at all times will allow the driver to see a vehicle 15 m directly behind the solar car and up to 30° off center. The system must provide the driver with a single reflex type image and must operate without driver input. The driver will be required to identify the direction of an arrow with a 200 mm thick brush stoke on a 1 m2 board held about 1 m off the ground.

9.5.E.2 If equipped: the camera and view screen shall be fixed in position such that road bumps and vehicle vibration will not alter the viewing angles.

9.5.E.3 If equipped: the view screen shall be positioned such that the driver shall be able to see the view screen while seated in normal driving position.

10.3 Occupant Cell

The occupants cell may not subject the solar car occupants to excessive strain during normal operation, and must be designed to protect the occupants from injury in the event of an accident. The occupants must be provided adequate space for safe operation of the vehicle. Care needs to be taken in the design and construction of the vehicle to minimize the risk that any shafts or sharp objects could penetrate the cockpit in the event of a crash and potentially injure the occupants.

10.3.A Definitions

The following definitions shall be incorporated into the Regulations:

10.3.A.1 Roll Cage: is the structural cage that encompasses the drivers head and upper body as per Reg.10.3.G. The roll cage shall be integrally attached to the structural chassis of Reg.10.3.F.

10.3.A.2 Roll Bars: are the series of tubular bars which comprise the roll cage.

10.3.A.3 Structural Chassis: is the tubular frame / monocoque composite chassis / hybrid of composite & tubular frame which encompasses the occupant’s body, and to which the vehicle suspension system is connected.

10.3.B Occupant Seats

10.3.B.1 Single-occupant solar cars shall only have one seat.

10.3.B.2 Multi-occupant solar cars shall be designed to carry more than one occupant.

10.3.B.3 Each solar car occupant must have a seat that faces forward at an angle less than 10 degrees from the forward direction of travel.

10.3.B.4 Each seat must have a back and a head restraint Reg. 10.3.G.8. The distance from the hip point to the top of the head restraint must be at least 800 mm for front seats and those of a single-occupant solar car and at least 750 mm for rear seats. (49 CFR 571.202a - Standard No. 202a; Head restraints). The hip point may be approximated as shown in the diagram below. Any additional seat padding must be included in this measurement.

Figure 10.1 - Hip Point Definition

10.3.B.5 Each occupant’s heels must be below their hip point.

10.3.B.6 The angle between each occupant’s shoulders, hips and knees must be more than 90 degrees.

10.3.B.7 Any additional seat padding must be positively secured to the seat.

10.3.C Occupant Space

10.3.C.1 The occupant space for each occupant’s upper torso shall be defined by an arc defined with an 835 mm radius measured from the hip point as defined in Appendix B of the occupant and projects forward 45 degrees from vertical, 25 degrees rearwards and 7 degrees side-to-side from the centerline of the occupant. Note: This minimum occupant space requirement is based on a 50-percentile male and does not allow for a helmet. Taller team members may need more occupant space.

10.3.C.2 The solar car structure, including the windscreen must lie wholly outside the occupant space. The steering wheel, mirrors seat backs and head restraints may be inside the occupant space but must be designed to minimize the risk of injury to the occupant.

10.3.C.3 The driver’s head must be above and behind the driver’s feet. The seat must be appropriately constructed with a solid base and back rest.

Appendix B. Occupant Space Diagram

10.3.G Roll Cage

10.3.G.2 The roll cage and structural chassis combination shall encompass the occupant in all directions. The roll cage must encompass the occupants well enough that a cloth stretched around the roll cage is clear of a full free range of motion of the occupant’s head including helmet with the safety belts in use.

10.3.G.7 Note, the forward portion of the front roll cage shall be far enough forward that in the event of a collision causing the occupants head to move forward, the furthest extent of the occupant’s head is still within the confines of the roll cage.

10.3.G.8 The roll cage must be padded with energy-absorbing material which is bonded and secured to the roll cage, meeting SFI-45.1 or FIA 8857-2001 Type A or B, or better, wherever it may come into contact with the occupant’s helmet covering 50% of the roll cage member. In addition, a headrest of at least 20 mm thick resilient material must be securely mounted behind the occupant’s head without the use of cable ties, fabric straps, or temporary attachments. The headrest must support the occupant’s head in normal driving position.

10.3.G.9 There must be 50 mm of clearance in all directions between any member of the roll cage and the helmets of the occupants seated in the normal driving position. There must be at least 30 mm of clearance between the occupant’s helmet and the padding to allow for free movement of the occupant’s head.

WSC 2019 Regulations (V3.0 - Released October 17, 2018)

2.11 Occupant cell
2.11.1 Solar car occupants must be enclosed in an occupant cell designed to protect them from injury.
2.11.2 Teams must provide documentation that specifies which parts of their solar car constitute the occupant cell.
2.11.3 When occupants are seated normally, with safety-belts and helmets on, no part of any occupant or their helmet may intersect with the convex hull of the occupant cell.
2.11.4 No point of any occupant’s helmet may lie within 50 mm of the convex hull.

Imagine stretching a rubber skin around the occupant cell; no part of any occupant may touch the skin, and helmets must be more than 50 mm from the skin.

2.11.5 Each team must provide a description of how the occupant cell will protect the occupants from frontal impacts, side impacts and rollover impacts. This description must be endorsed by the team’s certifying engineer.

For teams wishing to do finite element analysis of the occupant cell, the minimum test loads are:
• frontal impact: a 5 g load, opposing the direction of travel, applied to the front of the occupant cell in an area less than 250 mm high and less than 600 mm wide
• side impact: a 5 g load into the side of the occupant cell, applied adjacent to the driver’s torso in an area less than 250 mm high and less than 600 mm wide
• top impact: a load with components 5 g down, 1.5 g sideways and 4 g backwards, applied at each possible area of contact between the occupant cell and the ground when the occupant cell is upside down; the contact area for each test load must have a diameter less than 150 mm.

Loads are based on the fully-laden mass of the solar car. Teams must be able to show that the occupant cell structure will not fail with these test loads, and that any deformations will not impinge on the occupants. To reduce the risk of injury from impacts, the interior of the occupant cell adjacent to each occupant’s pelvis, abdomen, thorax and shoulder should be covered with energy absorbing material at least 50 mm thick and with a compressive strength of 500–1000 kPa.

2.11.6 The solar car body and occupant cell must be designed so that parts, such as the solar collector, cannot detach and injure occupants.

2.12 Seats2.12.1 Cruiser solar cars must be designed to carry more than one occupant.2.12.2 Each solar car occupant must have a seat that faces forward at an angle less than 10°, about a vertical axis, from the forward direction of travel.2.12.3 Each seat must have a back and a head restraint. Each head restraint must be entirely behind the occupant’s head. The distance from the hip point to the top of the head restraint must be at least 800 mm for front seats and at least 750 mm for rear seats (UNECE Regulations 17 and 25). The hip point may be approximated as shown in the diagram below.

2.12.4 Each occupant’s heels must be below their hip point.

2.12.5 The angle between each occupant’s shoulders, hips and knees must be more than 90°.

2.12.6 No more than four solar car seats may be occupied while driving.

2.13 Occupant space2.13.1 Occupant space for each seat must comply with Section LK of the Australian National Code of Practice for Light Vehicle Construction and Modification, as shown in the following diagram. The 835mm radius arm must be able to move 45° forwards, 25° backwards and 7° either side of vertical. The solar car structure, including the windscreen, must lie wholly outside the occupant space. The steering wheel, mirrors, seat backs and head restraints may be inside the occupant space, but must be designed to minimise the risk of injury in a crash.This minimum occupant space requirement is based on a 50-percentile male and does not allow for a helmet. Taller team members may need more occupant space.

2.17 Forward and sideward vision2.17.1 Each driver, when seated in the normal driving position with safety-belt and helmet on, must be able to identify 75 mm high letters at every point of forward travel that is:

4m from the driver’s eyes, and
between 0.4m below eye level and 0.7m above eye level, and
between 100° left and 100° right of the direction of travel.
2.17.2 Forward and sideward vision must be achieved without the aid of mirrors, lenses or electronic vision systems.
2.17.3 The windscreen that is used for forward and sidewards vision must have an optical transmittance more than 75%.
2.17.4 Traffic light colours must be discernible through the windscreen.

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