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SAE J586 2024: Unified Stop Lamp Requirements for All Vehicle Widths
The newly revised SAE J586 (May 2024) consolidates requirements for stop lamps used on motor vehicles less than, equal to, or greater than 2032 mm in overall width. This standard merges the previous SAE J2261 for wider vehicles into a single document, simplifying compliance and design for manufacturers of passenger cars, trucks, buses, and trailers. Whether you are designing stop lamps for a compact car or a heavy-duty tractor-trailer, this standard provides a unified set of test procedures, performance criteria, and identification codes.
Key Consolidation: SAE J2261 is now obsolete and its requirements have been fully integrated into SAE J586. Users searching for J2261 will be redirected to this updated standard.
Key Updates and Identification Codes
The standard applies to stop lamps—commonly known as brake lights—for vehicles of all widths. The revision introduces several important changes:
- Title expanded to explicitly include vehicles less than, equal to, or greater than 2032 mm in overall width.
- Definition updates for “stop lamp arrangement” and “multiple lamp arrangement” to align with other SAE documents.
- Addition of identification code S2 for stop lamps used on vehicles 2032 mm or more in overall width. The existing code S remains for narrower vehicles.
- References updated to reflect current SAE, federal (FMVSS 108, CMVSS 108), and United Nations regulations.
Lamps are classified by their effective projected luminous lens area, which determines the minimum luminous intensity values they must meet. The table assigns photometry figures based on size:
| Size Category | Identification Code | Vehicle Width | Minimum Luminous Intensity (cd) |
|---|---|---|---|
| Size 1 | S or S2 | All widths | See Figure 1 in standard |
| Size 2 | S | Less than 2032 mm | See Figure 2 |
| Size 3 | S | Less than 2032 mm | See Figure 3 |
Design Insight 🛠️: The standard uses the effective projected luminous lens area to classify lamps into three sizes, with corresponding photometry figures. Lamps for wider vehicles (S2) must also meet additional requirements in SAE J2139, ensuring adequate visibility for larger vehicle profiles.
⚠️ Common Mistake: Do not confuse “S” and “S2” codes. The “S2” code is reserved exclusively for stop lamps on vehicles with an overall width of 2032 mm or more. Using the wrong code can lead to non-compliance with FMVSS 108.
Testing and Performance Validation
Stop lamps must pass a series of environmental and durability tests specified in SAE J575 (for vehicles less than 2032 mm) or SAE J2139 (for vehicles 2032 mm or more). These include vibration, moisture, dust, corrosion, photometry, and warpage tests. The standard also outlines color requirements (per SAE J578) and material specifications for plastic optics (per SAE J576).
For installation, the standard provides guidelines to ensure the stop light function is visible and unobstructed. Figure 4 defines the unobstructed projected area or luminous intensity visibility requirements.
Frequently Asked Questions
What is the difference between S and S2 identification codes?
S is for stop lamps on vehicles less than 2032 mm in overall width. S2 is for stop lamps on vehicles 2032 mm or more in overall width. The S2 code signifies compliance with additional requirements from SAE J2139.
Does SAE J586 replace SAE J2261?
Yes. The May 2024 revision of SAE J586 merges the stop lamp requirements from SAE J2261. SAE J2261 has been made obsolete, and users are directed to SAE J586.
What photometry tests must a stop lamp pass?
The photometry test measures luminous intensity at various test points. The standard defines minimum intensity values for three size categories (Sizes 1, 2, 3) based on the effective projected luminous lens area. Lamps must also meet chromaticity requirements to emit a red light.
🔍 For more detailed specifications, designers should refer directly to SAE J586_202405, the full standard available from SAE International.
