Trailer Reference

Complete Trailer Types Guide

Side-profile diagrams, legal dimensions, and broker use cases for every trailer type used in North American freight — plus axle configurations, tandem, tridem, quad, and lift axles.

12 min read · 10 trailer types · 5 axle configurations · Updated August 2026

📦 Dry Van ❄️ Reefer (Refrigerated)🟩 Flatbed 📐 Step Deck (Drop Deck)⬇️ Double Drop (Lowboy)🔓 RGN (Removable Gooseneck)🔲 Container Chassis 🏹 Conestoga 🚗 Roll-on/Roll-off (Auto Hauler)🪵 Rack and Tarp (Pipe / Lumber)🚛 B-Train / Maxi (Double Trailer)⚙️ Axle Configurations

📦

Dry Van

The most common trailer in North America — fully enclosed, weathertight, palletized freight.

Side profile

Specifications

Standard length	53 ft (48 ft regional)
Interior width	98–100 in (8'2"–8'4")
Interior height	108–110 in (9'–9'2")
Floor height	50–54 in from ground
Max overall height	~13'4" (under 13'6" legal)
Max payload (53')	42,000–45,000 lbs
Pallet positions	Up to 30 standard GMA (48×40)
Door opening	94–96 in W × 102–106 in H

✓ Common Freight

Palletized CPG and retail
Packaged food (non-perishable)
Paper products, textiles, clothing
Electronics (boxed)
Automotive parts (boxed)
Tile, drywall, flooring on pallets

✗ Cannot Haul

Temperature-sensitive freight
Top-loading or crane-loaded freight
Oversized or overweight freight

💡

Broker Tip Always confirm actual weight and pallet count — "full truckload" is not a spec. Light bulky freight (tissue, clothing) cubes out at 30 pallets/~18,000 lbs. Heavy freight (beverages) hits 44,000 lbs at 20–22 pallets.

❄️

Reefer (Refrigerated)

Temperature-controlled enclosed trailer. Identical profile to dry van with active refrigeration unit at nose.

Side profile

Specifications

Standard length	53 ft
Interior width	96–98 in (insulation reduces ~2")
Interior height	100–104 in (insulation reduces ~6")
Floor height	52–56 in from ground
Temp range	-20°F to +70°F typical
Max payload	42,000–44,000 lbs (reefer unit ~3,000 lbs)
Reefer fuel	0.4–0.8 gal/hr diesel or electric
Pallet positions	Up to 28–30 GMA pallets

✓ Common Freight

Fresh produce (33°F–41°F)
Dairy, eggs, meat, poultry
Frozen goods (-10°F to 0°F)
Pharmaceuticals (strict temp logs)
Beer and beverages
Chocolate on hot lanes

✗ Cannot Haul

Non-refrigerated freight (higher cost, waste capacity)
Freight too wide/tall for interior

⚠️

Watch Out Confirm the set-point temp before booking — a carrier running at 34°F cannot add a frozen stop. Ask if a printed temp report (download) is required at delivery. Reefer loads almost always carry a rate premium over dry van.

🟩

Flatbed

Open-deck trailer with no sides or roof. Loaded from any direction by forklift or crane.

Side profile

Specifications

Standard lengths	48 ft (most common), 53 ft
Deck width	8'6" (102 in)
Deck height	58–62 in from ground
Max freight height	Up to 8'6" without permit (13'6" total)
Max payload (48')	47,000–48,000 lbs
Max payload (53')	43,000–45,000 lbs
Stake pockets	Every 24–36 in along edges
Securement	4+ straps or chains per FMCSA 393

✓ Common Freight

Structural steel: beams, columns, pipe
Steel coils, sheet, plate
Lumber and building materials
Construction equipment under 8'6" tall
Large machinery and industrial equipment
Agricultural equipment and wind energy components

✗ Cannot Haul

Freight requiring weather protection (use conestoga)
Freight over 8'6" wide without permits
Dock-loading freight (flatbed is side/top load only)

📌

Broker Note Tarping is set by the shipper — confirm before quoting. Tarp surcharges add $50–$200. Steel coils almost always require tarping. Coated or finished goods need wrapping. Never assume tarp is included in the carrier quote.

📐

Step Deck (Drop Deck)

Two-level flatbed: a short upper deck at standard height drops to a longer lower deck for taller freight.

Side profile

Specifications

Overall length	48–53 ft typical
Upper deck length	10–12 ft
Lower deck length	37–40 ft
Upper deck height	62–64 in from ground
Lower deck height	38–42 in from ground
Max freight height	Up to 9'6" on lower deck (no permit)
Deck width	8'6" (102 in)
Max payload	43,000–46,000 lbs

✓ Common Freight

Freight 8'7"–9'6" tall that won't clear a flatbed
Agricultural machinery: combines, headers, planters
Construction equipment: skid steers, scissor lifts
Forklifts and material handling equipment
HVAC rooftop units, large compressors
Tall generators and industrial machinery

✗ Cannot Haul

Freight taller than 9'6" without OW permits
Very long freight that won't bridge one level

💡

Broker Tip Step deck gives ~18–20" more freight height than flatbed on the lower deck. If equipment is 9' tall with a flat base, step deck is almost always the right call before going to a double drop. Confirm whether equipment can be craned on or must drive on (that's an RGN).

⬇️

Double Drop (Lowboy)

The lowest deck height available — gooseneck, ultra-low well, and raised tail for the heaviest and tallest loads.

Side profile

Specifications

Well deck height	18–24 in from ground (19–22" most common)
Well deck length	24–29 ft usable
Gooseneck height	~52–60 in from ground
Max freight height	Up to 11'2"–11'6" in well (no permit)
Max payload	40,000–55,000 lbs (tandem axle)
Heavy config	100,000+ lbs with added axles
Axle count	2–4+ axles depending on load weight
Typical OW permit	Required above 80,000 lbs GVW

✓ Common Freight

Large construction equipment: excavators, bulldozers
Heavy industrial machinery: transformers, turbines
Oil field equipment: pump jacks, BOPs
Military vehicles and armored equipment
Freight 10'–11'6" tall

✗ Cannot Haul

Equipment too long for the well (needs extendable)
Equipment that must drive on (needs RGN)
Freight over 11'6" without oversize permits

⚠️

Watch Out Always get all four dimensions + weight before calling carriers. No dimensions = no quote. Transit is slower — daylight only, no Sunday in many states, pilot cars often required. Permit lead time: 1–5 days per state crossed.

🔓

RGN (Removable Gooseneck)

Like a double drop, but the front gooseneck detaches — allowing equipment to drive directly onto the well deck.

Side profile

Specifications

Well deck height	18–24 in from ground (same as double drop)
Loading method	Drive-on from front OR crane-on
Gooseneck removal	15–30 min setup time at shipper
Well deck length	24–36 ft depending on config
Max payload	40,000–70,000 lbs standard
Heavy config	100,000+ lbs with additional axles
Width standard	8'6" well; 10'–14'6" with outriggers

✓ Common Freight

Self-propelled equipment: dozers, excavators, graders
Equipment with limited crane points
Wheeled or tracked machinery under own power
Armored vehicles and military equipment
Large agricultural equipment with complex attachment points

✗ Cannot Haul

Freight that cannot drive or be craned on
Anything not suited for a well-deck approach

💡

Broker Tip Ask the shipper: "Can it be craned, or does it need to drive on?" Drive-on = RGN required. Crane = double drop or RGN both work. RGN rates carry a premium over standard double drop. Confirm flat ground is available at the shipper for gooseneck removal.

🔲

Container Chassis

Low-profile frame designed to carry ISO intermodal containers from ports and rail yards.

Side profile

Specifications

Chassis lengths	20 ft, 40 ft, 45 ft, 48 ft, 53 ft
Std container H	8'6" (ISO standard)
High-cube H	9'6" (HC — most common in NA)
Platform height	48–52 in from ground
Max GVW	80,000 lbs US federal
40ft payload	~44,000–48,000 lbs
Twist lock type	ISO corner casting (20ft or 40ft spacing)
Pool equipment	Often chassis pool — not carrier-owned

✓ Common Freight

Port drayage — ocean container to warehouse
Rail drayage — container from intermodal ramp
Import/export freight in ISO containers
Cross-border CA–US sealed container moves
Transloading operations

✗ Cannot Haul

Freight not in an ISO container
Oversized containers exceeding chassis specs

⚠️

Watch Out Chassis pool availability is a real constraint at congested ports (LA/LB, Savannah, Prince Rupert). Confirm chassis before booking. Per-diem charges apply if container is not returned on time. Chassis splits add cost — avoid when possible.

🏹

Conestoga

A flatbed with a rolling tarp system — loads like a flatbed from the side, protects freight like an enclosed trailer.

Side profile

Specifications

Base trailer	Flatbed — 48 ft or 53 ft
Deck height	58–62 in from ground (same as flatbed)
Interior height	~100–108 in under the tarp frame
Tarp system wt	2,000–3,500 lbs (reduces payload)
Max payload	43,000–46,000 lbs
Side loading	Yes — tarp rolls back from either side
Deck width	8'6" usable (same as flatbed)

✓ Common Freight

Coated or finished steel (full tarp on all sides)
Lumber and building materials needing full coverage
Paper rolls and coils (forklift-loaded, needs coverage)
Large weathersensitive machinery (top-loaded)
Glass and building facade materials

✗ Cannot Haul

Temperature-sensitive freight
Freight too tall for the tarp frame

📌

Broker Note Conestoga availability is much lower than flatbed. If unavailable, a flatbed with full wrap + tarp may be negotiated depending on commodity. Carriers with Conestogas command a rate premium — book early on tight lanes.

🚗

Roll-on/Roll-off (Auto Hauler)

Multi-level open trailer with rear ramps — vehicles and equipment drive on under their own power.

Side profile

Specifications

Type	Open multi-level (7–10 vehicles typical)
Overall length	75–80 ft (combination unit)
Deck levels	2 (upper hydraulic, lower fixed)
Vehicle height	~7'0"–8'0" per level
Total payload	~30,000–40,000 lbs (7–9 vehicles)
Loading	Rear ramp at ground; upper via hydraulic ramp
Rate basis	Per vehicle (not per truckload)

✓ Common Freight

New vehicle OEM deliveries (plant → dealer, port → dealer)
Used vehicle transport (auction-to-auction)
Fleet vehicles for rental and corporate fleets
Non-running vehicles within weight/size limits

✗ Cannot Haul

Lifted trucks, buses, large RVs (too tall per level)
Oversized vehicles (>8'6" — need flatbed)
Standard freight (not a vehicle)

📌

Broker Note Auto transport is a separate niche — rates are per vehicle, not per truckload. Most auto transport is brokered through specialized boards (Central Dispatch). Standard freight brokerage load boards are not the right tool for vehicle moves.

🪵

Rack and Tarp (Pipe / Lumber)

Flatbed fitted with metal side racks and a full-length tarp — purpose-built for pipe, lumber, and long bundled freight.

Side profile

Specifications

Base trailer	Flatbed 48 ft (most common)
Deck height	58–62 in from ground
Rack height	24–36 in above deck
Rack spacing	Stakes every 4–6 ft along deck
Max payload	45,000–48,000 lbs
Tarp coverage	Full-length (up to 3 tarps for long loads)
Typical commodity	Dimensional lumber, OSB, pipe, rebar

✓ Common Freight

Framing lumber and dimensional wood products
OSB, plywood, engineered wood panels
Steel pipe and PVC pipe (bundled)
Rebar and wire rod bundles
Structural conduit and tubing

✗ Cannot Haul

Freight requiring full enclosure or temp control
Freight too tall for the tarp to cover

💡

Broker Tip Confirm how many tarps the shipper requires — lumber often needs 1–3. Lumberyards and building suppliers often have tight receiving windows. Confirm whether a delivery appointment is required before booking; late deliveries on lumber sites cause downstream delays.

🚛

B-Train / Maxi (Double Trailer)

Two full-length trailers connected via a fifth-wheel dolly on the back of the first trailer — common in Canada.

Side profile

Specifications

Configuration	Two 28–28.5 ft trailers or two 53 ft (B-train)
Overall length	Up to 95 ft combined (province-dependent)
Trailer type	Dry van most common; flatbed B-train also used
Max payload	~90,000–140,000 lbs combined (province rules)
Common provinces	AB, SK, MB, ON (permitted on major highways)
Axle config	Tandem or tridem on each trailing unit
Rate basis	Per km/mile combined — not per trailer

✓ Common Freight

High-volume dry goods on major Canadian corridors (AB → ON)
Oil patch supply in Alberta
Retail distribution to DCs on BC/AB/SK routes
Grain and agricultural bulk (B-train hopper combos)

✗ Cannot Haul

Urban deliveries (restricted on city streets)
US-bound freight (doubles rules differ by state)
Freight that cannot be co-loaded across two trailers

⚠️

Watch Out B-trains are regulated at the provincial level — not all provinces allow the same configuration or weight. Always confirm the specific corridor and weight with the carrier. Cross-border B-train moves into the US require knowledge of individual state doubles regulations.

⚙️ Axle Configurations

The number and type of axles determines legal weight limits and operating costs. Every broker should understand what "tandem", "tridem", "quad", and "lift axle" means — you hear these terms on every heavy haul quote.

Tandem Axle

Two axles spaced ~52" apart. Standard on most trailers. US federal limit: 34,000 lbs for the axle group. In Canada, a tandem-rear truck combination typically operates at up to ~48,000 lbs GVW depending on province.

Max weight: 34,000 lbs group (US federal) · ~48,000 lbs GVW (CDN)

Used on: Standard on all dry van, reefer, flatbed, step deck trailers

Tri-Axle (Tridem)

Three axles grouped together. Common on heavy haul, B-trains, and tanker/aggregate trailers in Canada. A tri-axle combination typically operates at up to ~60,000 lbs GVW in Canadian provinces.

Max weight: Up to ~60,000 lbs GVW (CDN provincial typical)

Used on: Heavy haul, B-train rear units, aggregate/tanker in Canada

Quad Axle

Four axles at the rear of the trailer or drive unit. Used on the heaviest legal loads — typically with a provincial permit. Common on concrete mixers, aggregate dumps, and heavy haul lowboys.

Max weight: Up to ~90,000 lbs GVW (CDN provincial permit)

Used on: Heavy haul lowboys, superload configurations, Canadian aggregate trailers

Super Single / Wide-Base

One wide tire per axle position replacing the traditional dual tires. Lighter weight, better fuel economy, used on weight-sensitive loads (max payload applications).

Max weight: Same legal limits per axle; saves ~1,200 lbs vs dual-tire setup

Used on: Max-payload dry van and reefer runs; premium carrier fleets

Lift Axle (Drop Axle)

A retractable third axle that raises when empty and lowers when loaded. Common on flatbeds and heavy-haul configurations — allows legal weight when loaded without dragging an extra axle empty.

Max weight: Adds 20,000 lbs capacity when deployed; raised when empty to save tire wear

Used on: Flatbeds on heavy lanes, concrete pumpers, dump trailers, some step decks

Tandem axle close-up

U.S. Federal Axle Weight Limits (FHWA) — Standard Interstate

Axle Configuration	US Federal Limit	Canadian (typical GVW)	Notes
Steer axle (single)	12,000 lbs	~13,000 lbs	Front axle of tractor
Single drive axle	20,000 lbs	~20,000 lbs	Single rear axle (non-tandem)
Tandem drive axles	34,000 lbs	~34,000 lbs	Two rear tractor axles combined
Tandem trailer axles	34,000 lbs	~48,000 lbs GVW	CDN GVW is for full truck combination; higher gross allowed
Tridem (3-axle group)	Bridge formula	~60,000 lbs GVW	CDN provinces; exact limit varies by province and axle spread
Quad axle	Bridge formula	Up to ~90,000 lbs GVW	Permit required; AB/SK/MB most permissive
Gross vehicle weight	80,000 lbs	Varies by province	CDN provincial GVW often higher; permits extend further

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