Overview
ISO 13674-2:2016, “Road vehicles - Test method for the quantification of on-centre handling - Part 2: Transition test,” defines a repeatable laboratory-style driving manoeuvre and data‑analysis schedule to quantify the on-centre handling behaviour of road vehicles. Applicable to passenger cars (per ISO 3833) and light trucks (N1 category), the standard measures vehicle response to a controlled steering input while minimizing environmental disturbances. The manoeuvre is not representative of everyday driving but is valuable for comparing steering feel and precision under tightly controlled conditions.
Key topics and technical requirements
- Purpose and principle
- Quantifies on‑centre handling at low lateral accelerations (typically ≤ 1 m/s²).
- Tests are run with the vehicle driven nominally straight at constant forward speed while driver inputs and vehicle responses are recorded.
- Measured variables
- Mandatory: steering‑wheel angle (δ), steering‑wheel torque (M), yaw velocity (dψ/dt), longitudinal velocity (vx), lateral acceleration (ay).
- Recommended: steering‑wheel angular velocity and roll angle.
- Measuring equipment and accuracy
- Equipment must meet ISO 15037-1 requirements.
- Typical recommended maximum errors (combined transducer + recorder): steering‑wheel angle ±0.1°, torque ±0.1 Nm, yaw velocity ±0.1°/s, lateral acceleration ±0.1 m/s².
- Test conditions
- Test track and environmental conditions follow ISO 15037-1; lateral surface gradient should not exceed 1%.
- Care is required to avoid added friction/inertia from steering robots or transducers affecting torque measurements.
- Data processing and outputs
- Time histories and characteristic plots (e.g., steering torque vs. angle, yaw rate vs. angle) are specified for evaluation and presentation of results.
- Limitations
- Results represent a narrow aspect of vehicle dynamics and should not be over‑generalized; regulatory use requires proven correlation with safety outcomes.
Practical applications and users
ISO 13674-2 is primarily used by:
- Vehicle manufacturers and chassis/steering engineers for handling benchmarking and tuning.
- Automotive test laboratories conducting comparative handling evaluations.
- Tier‑1 suppliers of steering systems and tyres for component validation.
- Vehicle dynamics researchers studying steering feel, precision, and low‑lateral‑acceleration behaviour.
Benefits include repeatable, discriminatory handling metrics that support design decisions, component selection, and quality control. Users should combine ISO 13674-2 data with other tests (e.g., weave test) and real‑world assessments for comprehensive handling evaluation.
Related standards
Keywords: ISO 13674-2, on-centre handling, transition test, vehicle dynamics, steering-wheel torque, yaw velocity, lateral acceleration, ISO test method.