Scale Explorer

Vehicles

How big is a semi truck?

Semi truck · Tractor with a long-haul semitrailer (interstate design vehicle)

Overall length (WB-67 design vehicle)
≈ 23 m 74 ft approx.
Height (typical state limits)
4.1–4.3 m 13.5–14 ft range
Width (federal limit)
2.59 m 8 ft 6 in
Maximum gross weight
up to 36.3 t 80,000 lb maximum
Show
Human, Car, School bus, Semi truck drawn to the same scaleHuman: height 1.61–1.75 m. Car: length 4.915 m. School bus: length (65/66-passenger type c) ≈ 10.86 m. Semi truck: overall length (wb-67 design vehicle) ≈ 23 m.Human: 1.61–1.75 mCar: 4.915 mSchool bus: ≈ 10.86 mSemi truck: ≈ 23 mSemi truck≈ 23 mSchool bus≈ 10.86 mHuman1.61–1.75 mCar4.915 m
Everything is drawn to the same scale, standing on the same ground line. Silhouettes are simplified outlines scaled to the measured dimension. A faded outline shows the top of a size range.

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Dimensions

MeasurementMetricImperialNotesSource
Overall length (WB-67 design vehicle) ≈ 23 m ≈ 74 ft Long-haul tractor-semitrailer that road designers plan for; real rigs vary. Approximate [1]
Height (typical state limits) 4.1–4.3 m 13.5–14 ft Most state height limits range from 13 ft 6 in to 14 ft; there is no federal height limit. Range: varies [2]
Width (federal limit) 2.59 m 8 ft 6 in Width that states must allow on the National Network [3]
Maximum gross weight up to 36.3 t up to 80,000 lb Federal gross vehicle weight limit. Maximum [3]
Minimum semitrailer length states must allow at least 14.6 m at least 48 ft Federal minimum for the semitrailer in a tractor-semitrailer combination [3]

About the semi truck

A semi truck is a tractor unit pulling a semitrailer. Road designers use the WB-67 'interstate' design vehicle, with a 67 ft wheelbase and an overall length of about 74 ft, to represent long-haul tractor-trailers. Federal rules set the width at 102 inches on the National Network and the gross weight limit at 80,000 lb, while height limits are set by the states.

  • States may not impose an overall length limit on a tractor-semitrailer combination on the National Network. [2]

How many fit?

  • ≈ 13 × Human · height lined up end to end match the Semi truck · overall length (wb-67 design vehicle)
  • ≈ 430 × Human · body mass on the scales weigh as much as Semi truck · maximum gross weight
  • ≈ 1.8 × City bus · length over bumpers lined up end to end match the Semi truck · overall length (wb-67 design vehicle)
  • ≈ 2.4–2.9 × City bus · curb weight on the scales weigh as much as Semi truck · maximum gross weight

Counts divide one sourced figure by another. "End to end" uses each object's main measurement; weight and volume rows appear only when both figures are sourced.

How it compares

  • 13× A semi truck is about 13 times as long as an average adult is tall. See side by side
  • 1.8× A semi truck is about 1.8 times as long as a city bus. See side by side
  • 1.9× A semi truck is about 1.9 times as long as a Brachiosaurus is tall. See side by side
  • 1/1.1 A semi truck is about as long as a tennis court. See side by side
  • 1/1.7 A Boeing 737 is about 1.7 times as long as a semi truck. See side by side
  • 1/2.6 The Leaning Tower of Pisa is about 2.6 times as tall as a semi truck is long. See side by side

Factors compare the overall length (wb-67 design vehicle) of a semi truck with each object’s own main measurement (height for a human). Where a size varies, the factor is given as a range.

Notes on these figures

  • Tractor-trailer lengths vary with the tractor and trailer. The 74 ft figure is the WB-67 design vehicle that road designers use for long-haul trucks.

Sources

  1. Seattle Department of Transportation (Streets Illustrated), 3.11 Freight. Accessed 24 September 2026.
  2. Federal Highway Administration, Federal Size Regulations for Commercial Motor Vehicles (FHWA-HOP-04-022). Accessed 24 September 2026.
  3. Federal Highway Administration, Vehicle Size and Weight Program Overview. Accessed 24 September 2026.

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