组合车辆测试

With a fully-charged air system, turn off the engine, release the parking brake; and time the air pressure drop. The loss rate should be less than three psi in one minute for combination vehicles, we do not add the additional second here because the brakes are released. / 气压充满后，熄火、释放驻车制动并计时气压下降；组合车辆在 1 分钟内的压降应 小于 3 PSI 。

One good rule says you need at least one second for each 10 feet of vehicle length at speeds below 40 mph. At greater speeds, you must add 1 second for safety. / 一个常用规则： 40 mph 以下 ，每 10 英尺 车长至少留 1 秒 ；更高速度需再 多加 1 秒 。

Rear wheel braking skids occur when the rear drive wheels lock. Because locked wheels have less traction than rolling wheels, the rear wheels usually slide sideways to "catch up" with the front wheels. With vehicles towing trailers, a drive-wheel skid can let the trailer push the towing vehicle sideways, causing a sudden jackknife. / 当 驱动轮 被锁死时抓地力更差，后轴会横向滑移来“追上”前轮；带挂车时，挂车会 把牵引车侧推 ，形成突然的折刀。

Use low gear range to begin raising the landing gear, once free of weight, switch to the high gear range. Raise the landing gear all the way up. Never drive with landing gear only part way up as it may catch on railroad tracks or other things. After raising landing gear, secure the crank handle safely. / 先用低速档开始摇起支腿，脱重后换高速档并 完全收起 ；切勿让其只升到一半——可能会 挂到道口 等障碍。收好后把摇柄固定在支架上。

Brake the same way, regardless of whether you have ABS on the tractor, the trailer, or both. / 无论 ABS 安装在牵引车、挂车，还是两者都有， 制动方法相同 ；ABS 只是帮助防抱死。

The trailer should be low enough that it is raised slightly by the tractor when the tractor is backed under it. If the trailer is too low, the tractor may strike and damage the trailer nose; if the trailer is too high, it may not couple correctly. / 挂车应略低于五轮，使牵引车倒入时能将其 轻微托起 。挂车太低可能顶伤鼻部，太高可能无法正确挂接。

With a fully-charged air system, turn off the engine, release the parking brake; and time the air pressure drop. The loss rate should be less than three psi in one minute for combination vehicles, adding one second if the brakes are applied. / 在空气系统充满时，熄火、释放驻车制动并记录气压下降速度。组合车在 1 分钟内的压降应小于 3 psi；若踩住脚刹，则允许值再增加约 1 psi（即约 4 psi）。

Large combination vehicles take longer to stop when they are empty than when they are fully loaded. When empty, the very stiff suspension springs and strong brakes give poor traction and make it very easy to lock up the wheels causing the tractor to jackknife. / 大型组合车在 空载 时比满载更难刹住；悬架更硬、制动更猛，抓地差、更容易抱死并导致折叠。

When a vehicle goes around a corner the rear wheels follow a different path than the front wheels, and this is called off-tracking or "cheating." Longer vehicles will off-track more. If there is more than one trailer, the rear wheels of the last trailer will off-track the most. / 车辆转弯时后轮走出的轨迹与前轮不同，称为“偏轨”。 车越长偏轨越大 ；若有多节挂车，最后一节的偏轨最大。

Make sure air and electrical lines are not tangled, pinched, dragging against tractor parts, and have enough slack for turns. / 确保气管与电缆 不缠绕、不被夹、不拖地 ，并 留足转弯余量 。

More than half of truck driver deaths in crashes are the result of truck rollovers. / 在卡车碰撞致死的事故中， 超过一半 源于车辆侧翻。

From cab, push in air supply knob or move tractor protection valve control from the emergency to the normal position to supply air to the trailer brake system. Check brake system for crossed air-lines. Shut engine off so you can hear the brakes. Check air brake system pressure gauge for signs of major air loss. / 在驾驶室按入挂车供气旋钮（或把保护阀从“紧急”拨到“正常”），向挂车供气；检查是否把气管接反；熄火并听是否有明显漏气。

The earliest way to notice that your trailer is jackknifing is to see it swinging out in your mirrors. / 挂车开始形成折刀（jackknife）的最早迹象，是你会从后视镜里看到它向外摆动。

The emergency line, also called the supply line, has two purposes. First, it supplies air to the trailer air tanks. Second, the emergency line controls the emergency brakes on combination vehicles. / 应急（供气）管路有两项作用：向挂车储气筒供气，并控制组合车辆的紧急制动。

Trailers that do not have spring brakes have emergency brakes, which work from the air stored in the trailer air tank. A major leak in the emergency line will cause the tractor protection valve to close and the trailer emergency brakes to come on, but the brakes will hold only if there is air pressure in the trailer air tank. Eventually, the air will leak away and then there will be no brakes. Therefore, it is very important for safety that you use wheel chocks when you park trailers without spring brakes. / 无弹簧制动的挂车只有储气筒里的空气能维持紧急制动；空气最终会 漏光 ，届时将 没有制动 ，因此务必使用 轮挡 。

Check glad hand seals and connect tractor emergency and service air-line to trailer emergency and service glad hand. Make sure air-lines are safely supported where they won't be crushed or caught while tractor is backing under the trailer. / 先检查手爪密封，并把牵引车的 应急与行车 两根气管接到挂车对应的手爪接头上；并确保气管悬挂妥当，不会在倒入时被挤压或钩住。

If you do cross the air-lines, supply air will be sent to the service line instead of going to charge the trailer air tanks. Air will not be available to release the trailer spring brakes. If the spring brakes don't release when you push the trailer air supply control, check the air-line connections. / 若把两根气管接反，供气会被送到行车管路而非充满挂车储气罐，导致 弹簧制动无法释放 。若按下挂车供气控制后仍不释放，应检查气管连接。

Check if fifth wheel is in proper position for coupling: The fifth wheel should be tilted down toward rear of tractor. / 对接前检查五轮姿态：应当 朝向牵引车尾部下倾 。

Glad hands are coupling devices used to connect the service and emergency air-lines from the truck or tractor to the trailer. / glad hands 是用于连接牵引车与挂车 行车 / 应急 空气管路的接头。

Put the tractor directly in front of the trailer. Never back under the trailer at an angle because you might push the trailer sideways and break the landing gear. / 没错！让牵引车 正对 挂车。切勿斜着倒入，否则可能把挂车横推，压坏支腿。