Vehicle category cheat sheet¶
GB 38031-2025 does not redefine vehicle categories — it inherits the standard Chinese vehicle classification system (originally derived from UN ECE category definitions). This page summarizes the categories used in the standard's test methods.
Categories used in GB 38031-2025¶
| Category | Description | Where it appears in GB 38031-2025 |
|---|---|---|
| M1 | Passenger vehicle, ≤ 9 seats including driver | Vibration test parameters (8.2.1.4 / Table 3) |
| N1 | Goods-carrying vehicle, max mass ≤ 3.5 t | Vibration test parameters (8.2.1.4 / Table 3) |
| All other M and N | Vehicles outside M1/N1 (buses, trucks, etc.) | Vibration test parameters (8.2.1.3 / Table 2) |
| N-class with min ground clearance ≥ 200 mm fully loaded | Trucks/commercial with high underbody clearance | Exempt from bottom impact test (8.2.16.1) |
Curb weight tiers (used in simulated collision)¶
The simulated collision test (8.2.3) scales pulse parameters by vehicle curb weight:
| Tier | Curb weight |
|---|---|
| Light | ≤ 3.5 t |
| Medium | > 3.5 t and < 7.5 t |
| Heavy | ≥ 7.5 t |
See the Simulated collision page for the full pulse envelopes (Table 6, 8 control points × 3 weight tiers × 2 axes).
Common category meanings (general reference)¶
These are the standard Chinese / UN ECE category definitions, included here for context:
| Category | Definition |
|---|---|
| M | Power-driven vehicles with at least 4 wheels designed for carriage of passengers |
| M1 | M-vehicles with ≤ 9 seats including driver (passenger cars) |
| M2 | M-vehicles with > 9 seats, max mass ≤ 5 t (small buses) |
| M3 | M-vehicles with > 9 seats, max mass > 5 t (large buses, coaches) |
| N | Power-driven vehicles with at least 4 wheels designed for carriage of goods |
| N1 | N-vehicles with max mass ≤ 3.5 t (light commercial vehicles) |
| N2 | N-vehicles with max mass > 3.5 t and ≤ 12 t (medium trucks) |
| N3 | N-vehicles with max mass > 12 t (heavy trucks) |
Engineering note (non-normative): The GB 38031-2025 vibration test treats M1 and N1 as a single class (per Table 3), while everything else (M2, M3, N2, N3) uses Table 2's tougher RMS values. The asymmetry exists because passenger cars and light commercial vehicles share similar suspension travel and road-input spectra, whereas heavier vehicles see different — generally more severe — vibration profiles.
Engineering note (non-normative): The bottom impact exemption for N-class vehicles with ≥ 200 mm ground clearance is geometric: at that clearance, underbody strikes from typical road debris are unlikely. Confirm clearance is measured fully loaded, not unladen — heavy commercial vehicles can lose 50+ mm of clearance at full load, which may push a borderline-exempt design back into scope.
Source: GB 38031-2025 clauses 8.2.1.3, 8.2.1.4, 8.2.3, 8.2.16.1. Vehicle category definitions per Chinese / UN ECE classification (not redefined in GB 38031-2025 itself).