This SAE Recommended Practice defines a set of measurements and standard procedures for motor vehicle dimensions. The dimensions are primarily intended to measure the design intent of a vehicle within a design environment (i.e., CAD). All dimensions in this practice can be measured this way.
In addition, some dimensions can be taken in an actual vehicle. If measurements are taken on physical properties, some differences in values should be expected. Also, care should be taken to not confuse design intent measurements with those taken on a physical property. It is intended that the dimensions and procedures described in this practice be generic in their application to both the HPM, described in SAE J826, and the HPM-II, described in SAE J4002. In some circumstances, the figures may only reflect one or the other.
Unless otherwise specified, all dimensions are measured normal to the three-dimensional reference system (see SAE J182), except ground-related dimensions, which are defined normal to ground. All dimensions are taken with the vehicle at curb weight unless otherwise specified.
All dimensions are measured on the base vehicle and do not include Regular Production Options (RPO) or accessory parts, unless otherwise specified.
Although many terms and dimensions use human body parts in their name, they should not be construed as measures that indicate occupant accommodation, capabilities, or comfort.
The 2009 revision of SAE J1100 represents a substantial overhaul of its contents. Specifically, dimension procedures and definitions have been:
harmonized with the Global Car manufacturer’s Information Exchange (GCIE),
coordinated with revisions to other SAE human accommodation standards,
synchronized with related definitions published by the International Standards Organization (ISO), including the use of HPM-II,
formalized with certain regulatory procedures defined by the United States (U.S.) Environmental Protection Agency (EPA), and
made consistent with some definitions found in the U.S. Code of Federal Regulations by the National Highway Traffic Safety Administration (NHTSA).
This revision reinstates some previously deleted SAE J1100 dimensions as well as some older versions of SAE J1100 dimensional definitions (e.g. W27). Additionally, many new definitions, dimensions, and figures were adopted. The document structure was subsequently reorganized for better consistency and to accommodate the number of changes. Most notably, cargo related dimensions were combined whether or not they were used in a Volume Index,, e.g. L505 – Pickup Body Length at Floor was moved from the Exterior Dimensions – Length Table to the Cargo Dimensions – Length Table.
The use of secondary suffixes was expanded to more logically consolidate dimension codes. Consistent with the previous two versions of SAE J1100, the location or designated seating position is identified by the first level suffix. The second level suffix is used to indicate a condition or direction. Additional details are provided in Section 4.
To assist the user in locating information of interest, a detailed Table of Contents was added. Content which underwent the most significant change is described below.
As in the past, all ground-related dimensions are taken normal to the ground plane for any loading condition. The definitions were editorially revised to clarify this point. SAE J1100 also reintroduces the ‘EPA-curb’ loading condition and describes specific dimensions taken at that load. Further, the document provides new dimensions measured at the manufacturer’s declared gross vehicle weight rating, and also assimilates the dimensions from the cancelled SAE J689.
The definition of Designated Seating Position (3.3.8) reflects pending changes to Federal Motor Vehicle Safety Standards (FMVSS) for vehicles manufactured on or after September 1, 2010. Related definitions for seating surface (3.3.17) and seating surface width (33.3.19) were added, as well as a new dimensional metric (SW26) for recording the total number of designated seating positions in each row of seats.
The method for locating the floor reference point (3.5.7) was modified to account for differences between the HPM devices and procedures described in SAE J826 and SAE J4002. This means that SAE J1100 dimensions are applicable to both.
Driver foot control dimensions were revamped to reflect a component-based numbering system which is described in Section 6. Control spacing dimensions based on ISO 3409 were adopted.
H-point travel path dimensions were revised and the points which describe the travel path limits were defined in Section 7. The dimensions were also suffixed (2, 3, 4, …) to allow the natural expansion into second and succeeding rows of seating.
Daylight Opening (DLO) was replaced with Design Glass Outline (DGO). Several regulated dimensions use or define Daylight Opening, or DLO, that were different from the DLO definition found in prior versions of SAE J1100. DGO was created to reduce confusion with these other dimensions and provide a unique measure devoid of regulatory interpretation.
The X-plane section for defining head clearances (W27, W35, and H35) was revised to reflect the side view top of contour consistent with the historical method. It replaces the use of an X-plane through the head contour centroid, first introduced in 2002. This change results in minimal differences in measures for the driver, and yields equivalent results for second and succeeding rows of seated occupants. The head contour centroid and the side view top of contour for these designated seating positions occur on the same X-plane. See SAE J1052.
Lastly, volume indices were expanded to include passenger volume and interior volume metrics congruent with EPA and NHTSA definitions. See Section 9 and Tables 31-33.