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What is the maximum permitted forward distance of a semi-trailer?
半挂车允许的最大前向距离（forward distance）是多少？
The maximum forward distance of a semi-trailer is 9.2 metres, measured from its rear axis to the centre of the kingpin.
半挂车的前向距离是从半挂车后轴基准线（rear axis）到牵引销中心（centre of the kingpin）的距离，最大为 9.2 米。
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Do not measure from the towing vehicle's rear axle to the front of the semi-trailer. The semi-trailer's own rear axis and kingpin define this measurement.
对半挂车而言，前向距离（forward distance）的测量基准是半挂车的后轴基准线与牵引销中心，最大为 9.2 米。不能把它理解为牵引车后轴到半挂车前端的距离。