Semi-trailer truckMexico

Learn traffic rules with clear explanations and visual examples in our illustrated book, designed to make studying simple and engaging.


30. Semi-trailer truck

A semi-trailer truck is a combination consisting of a road tractor and a semi-trailer used primarily for transporting goods. The semi-trailer is coupled to the tractor so that a significant part of its weight is supported by the tractor rather than entirely by its own wheels.

Semi-trailer trucks are commonly used for long-distance freight transport and may carry containers, refrigerated goods, liquids, bulk materials or other cargo. Special rules can apply concerning driving licences, maximum dimensions and masses, speed limits, lane use, overtaking, loading and driving and rest periods.

Semi-trailer truck
A Mercedes semi-trailer truck. (Regensburg, Germany)
Wikimedia.org • High Contrast • CC BY
What is a semi-trailer truck?

A semi-trailer truck consists of a powered road tractor coupled to a semi-trailer primarily used to transport goods.

What is a semi-trailer?

A semi-trailer is a trailer designed so that part of the trailer and a significant part of its load are supported by the towing tractor.

What is the difference between a semi-trailer and an ordinary trailer?

An ordinary trailer generally supports its own weight through its axles, while a semi-trailer transfers a substantial vertical load to the tractor through its coupling.

How is a semi-trailer connected to the tractor?

The semi-trailer is normally connected through a kingpin and fifth-wheel coupling mounted behind the tractor cab.

Why are semi-trailer trucks called articulated vehicles?

The tractor and semi-trailer are connected by a pivoting coupling, allowing the two parts to turn relative to each other when the combination changes direction.

Do you need a special licence to drive a semi-trailer truck?

Yes. Heavy articulated trucks normally require a heavy-goods-vehicle licence that also authorises the driver to tow a heavy trailer or semi-trailer. The precise licence categories differ between countries.

Do semi-trailer trucks have lower speed limits?

They often do. Many countries impose vehicle-specific maximum speeds on heavy goods vehicles, particularly on motorways and other high-speed roads.

Why do semi-trailer trucks need more space to turn?

The semi-trailer's rear wheels follow a tighter path than the tractor's front wheels. Drivers therefore need additional space when turning, particularly at narrow intersections.

Why should you leave extra distance behind a semi-trailer truck?

Large trucks can restrict your view of traffic ahead and require considerable stopping distance. Keeping an appropriate following distance improves visibility and reaction time.

Why should you take care when driving beside a semi-trailer truck?

Large trucks have substantial blind spots around the cab and trailer. Avoid remaining beside the vehicle unnecessarily and be particularly careful when the truck is turning or changing lane.

1 Mexico 2 Zone 3 Speed limit 4 Pedestrian warning 5 Speed bump 6 Stop sign 7 Give way 8 Railway crossing 9 School area 10 Rockfall 11 Curve 12 Chevron 13 Traffic lights 14 Driving licence 15 Reversing 16 Licence plate 17 Bus 18 Police 19 Ambulance 20 Pothole 21 Path 22 Particulates 23 Air pollution 24 Rush hour 25 Road code 26 Street gutter 27 Cargo bike 28 Forestry vehicle 29 Construction vehicle 30 Semi-trailer truck 31 Trolleybus 32 Speed pedelec 33 Delivery vehicle 34 Idling 35 Tow truck 36 Four-wheel drive 37 Road users 38 Bicycle 39 Motorcycle equipment 40 Rail track 41 Caravan 42 Trailer 43 Tow hitch 44 Fire truck 45 Siren 46 Convoy 47 Emergency vehicle lighting 48 Agricultural machinery 49 Electric bicycle 50 Electric vehicle 51 Pedelec 52 Quadricycle 53 Microcar 54 All-terrain vehicle 55 Van 56 Recreational vehicle 57 Scooter 58 Trikke 59 Personal mobility device 60 Skateboard 61 Segway 62 Kick scooter 63 Roller skates 64 Mailman 65 Hitchhiker 66 Toddler 67 Child 68 Disability 69 Motorail 70 km/h 71 mph 72 Speedometer 73 Ride height 74 Dirt road 75 Driving 76 Start-stop system 77 Manual transmission 78 Automatic transmission 79 Throttle 80 Tachometer 81 Steering wheel 82 Power steering 83 Visual scanning 84 Mirror 85 Fuel 86 Fuel gauge 87 Petrol 88 Diesel 89 Diesel exhaust fluid 90 Car insurance 91 First aid kit 92 Fire extinguisher 93 High-visibility clothing 94 First aid 95 Concrete step barrier 96 Barriers 97 Vehicle lights 98 Street lights 99 Dipped beam 100 High beam ...