RoRo vs Container Shipping for Vehicles and Machinery

If cargo has wheels or tracks and can roll, it can go on a RoRo vessel. If it fits inside a box, it can go in a container. Plenty of cargo qualifies for both, and that is where the decision gets expensive, because the two modes are measured, priced and regulated in genuinely different ways.

The short version: containers win on dense, box-shaped, weather-sensitive cargo that fits through a door opening of 2.597 m. RoRo wins on anything tall, self-propelled, or awkward enough that you would otherwise be buying an out-of-gauge slot. The rest of this guide is the numbers behind that, and the 2026 rule changes that most published guidance has got wrong.

What RoRo actually is

RoRo covers several distinct vessel types, and the differences matter more than the shared name suggests.

• PCC and PCTC (pure car carrier, pure car and truck carrier) are dedicated multi-deck vehicle carriers. Modern tonnage is large: Hoegh Autoliners' Aurora class carries up to 9,100 car equivalent units across 14 decks, with a maximum deck height of 6.5 m and a ramp rated to 375 tonnes.
• ConRo vessels carry both. Atlantic Container Line's G4 class runs roughly 3,800 TEU of container capacity alongside about 6,412 lane metres of RoRo deck, with a 420 tonne stern ramp and deck heights up to 7.4 m.
• RoPax are RoRo passenger ships. Keep them mentally separate, because as the fire safety section below shows, regulators treat passenger vessels under a far stricter regime than cargo vessels.

Capacity is quoted in CEU (car equivalent units) for vehicle decks and in lane metres for trailer and rolling freight decks. Both are deck-space measures, which is the first clue that RoRo economics are about area and height rather than the box count that drives container pricing.

The numbers that decide it: height, door and payload

Almost every RoRo-or-container argument resolves to three measurements. These are from a carrier's published equipment specification, so they are the numbers you will actually be held to:

Watch the high cube trap. A 40ft high cube is 2,896 mm tall on the outside, and that is the number people quote. The internal height is 2,700 mm and the door opening is 2,597 mm. A machine 2.7 m tall does not go through the door. More cargo is caught by the door opening than by the internal height, because loading is done through the door and not through the roof.

There are other container constraints worth knowing before you commit. A 40ft container carries a maximum spread load of about 3 tonnes per running metre of length, rising to 6 tonnes for steel-floor units. Flatrack lashing points are typically rated at 5,000 kg each, heavy cargo must sit on the main girder, and welding to a flatrack is not permitted. Our guides to container types and dimensions, high cube versus standard containers and special container equipment go deeper on each.

How each mode is charged, and why that usually decides it

This is the part that gets missed, and it explains more cost differences than vessel choice ever does.

• Containers are priced per box. A 40ft container costs what a 40ft container costs, whether it holds 3 tonnes or 28. Underfill it and you pay for air.
• Cars and vans on RoRo are priced per unit. One car, one rate.
• High-and-heavy and static RoRo cargo is priced on weight or measurement, commonly abbreviated W/M: whichever is greater of the cubic metres or the tonnes. ACL's published tariff shows exactly this split, with per-unit rates for cars and vans alongside per-W/M and per-metric-tonne rates for static and high-and-heavy cargo.

The consequence is a simple rule of thumb. A dense, heavy, box-shaped machine tends to win in a container, because you are paying for a box you can actually fill. A tall, light, awkward machine tends to win on a RoRo deck, because W/M rating does not punish you for a shape that would waste most of a container, and because you avoid buying an out-of-gauge slot.

Be sceptical of any specific out-of-gauge surcharge figure you find online. The numbers that circulate come from forwarder marketing pages rather than carrier tariffs, and OOG pricing is quoted case by case. Get it from the carrier for your actual piece.

Static cargo does not need wheels

A common misconception is that RoRo is only for things that drive. Non-self-propelled cargo travels on roll trailers, known in the trade as mafi trailers, which are towed on and off. Hoegh's roll trailer fleet runs from 20 to 80 ft with payloads up to 160 tonnes, and its superlow trailer is only 0.47 m high, which is precisely the point: a low bed is what lets a tall static machine fit under a deck that a container could never accommodate.

Some vessels also have liftable decks, so deck heights can be adjusted to the cargo. What carriers want in return is engineering detail before booking: drawings, weights, centre of gravity and an explanation of how the piece will be secured. Static cargo must have appropriate lashing points to secure it to the vessel, and a piece with nowhere to attach a lashing is a piece that will be refused. Our guides to project cargo and out-of-gauge shipping, breakbulk and lashing and bracing cover the securing side in detail.

The dangerous goods asymmetry nobody mentions

Here is the most under-reported technical difference between the two modes, and it runs opposite to most people's intuition.

Under the IMDG Code's special provision 961.1, a vehicle stowed in a vehicle space, special category space or RoRo space, or on the weather deck of a RoRo ship, is excepted from the Code, provided there is no sign of leakage from the battery, engine, fuel cell, gas cylinder or fuel tank. The European Maritime Safety Agency states the same exception in its own guidance, and adds the sting in the tail: when the vehicle is packed in a cargo transport unit, the exception does not apply to container cargo spaces of a RoRo ship.

In other words, the same vehicle can be outside the Code on a RoRo deck and inside it in a box. Shipping a vehicle in a container does not avoid dangerous goods handling. It is often what triggers it.

The quarter-tank rule is widely misattributed. The requirement that a flammable liquid fuel tank be no more than one quarter full, and in any case no more than 250 L, sits in special provision 962, which applies to vehicles that do not meet 961. Carriers such as Hoegh and ACL impose the quarter-tank limit on RoRo bookings anyway as a commercial condition, which is why it is universally believed to be an IMO rule for RoRo. Follow it, because your carrier requires it, but know which instrument it comes from when someone tells you a container shipment is exempt.

What changed on 1 January 2026. IMDG Amendment 42-24, adopted in May 2024, became mandatory at the start of this year and created three new UN entries for battery-powered vehicles: UN 3556 (lithium ion), UN 3557 (lithium metal) and UN 3558 (sodium ion). The generic UN 3171 classification is no longer permitted for lithium or sodium-ion powered vehicles. Carrier advisories are blunt about the consequence: declare the correct UN number, placard containers on all four sides where special provision 962 applies, and expect non-compliant shipments to be delayed, rejected or penalised. Classification for a battery vehicle is genuinely mode-dependent now, so confirm it with your carrier for the specific routing rather than assuming last year's answer still holds. Our guides to shipping lithium batteries and the dangerous goods declaration cover the paperwork.

What carriers require for vehicles

Published carrier conditions are fairly consistent, and Hoegh's are representative:

• Fuel: maximum one quarter tank for petrol, diesel and gas vehicles alike.
• Battery electric vehicles: maximum 50% state of charge, with enough charge left for basic driving on and off the vessel, and simple operating instructions left inside the car.
• Hybrids: maximum one quarter tank plus a recommended 50% state of charge.
• Nothing loose inside: no personal effects, household goods, waste, spare batteries of any kind, pyrotechnics, portable fuel tanks, medical supplies or non-original fire extinguishers.
• Documents: title and registration, bill of lading, shipping note, proof of insurance, bill of sale or commercial invoice where applicable, and photo identification.

The personal effects prohibition frustrates people shipping a car, but it is not arbitrary. Loose goods inside a vehicle are undeclared cargo for customs purposes, and they can carry their own dangerous goods status. They also defeat the condition that the vehicle is being carried as a vehicle.

Battery disconnection is the one to take seriously. The US National Transportation Safety Board investigated the total loss of the Hoegh Xiamen at Jacksonville in June 2020, a fire that destroyed 2,420 used vehicles and injured nine firefighters. Its probable cause was ineffective oversight of longshoremen, which did not identify that vehicle battery securement procedures were not being followed. A post-accident examination of 59 sampled vehicles found that not one complied with the battery disconnect procedure. These were used conventional vehicles, not electric ones.

Electric vehicles and the 2026 rules: what actually changed

You will read that the IMO introduced new rules for electric vehicles on RoRo ships after the Felicity Ace and Fremantle Highway fires. That is not what happened, and the detail is worth getting right because it affects what you can expect your carrier to do.

The instrument that entered into force on 1 January 2026 is IMO Resolution MSC.550(108), amending SOLAS chapter II-2. It is a general RoRo fire safety package and it does not mention electric vehicles, batteries or alternative fuels at all. The IMO itself describes the package as being about the fire safety of RoRo passenger ships. Of its requirements:

• The only new obligation reaching cargo ships, which is what a PCTC is, is fixed fire detection and alarm in vehicle, special category and RoRo spaces, and only for cargo ships built on or after 1 January 2026.
• Video monitoring, weather-deck water monitors rated at a minimum of 1,250 L/min, structural fire protection and decision-making signage are all passenger ship requirements.
• The widely quoted 2028 deadline is a retrofit date for existing passenger ships, not for car carriers.

The EV-specific work is still upstream. At the IMO's SSE sub-committee in March 2026, members agreed to prioritise car carriers and to develop two sets of interim guidelines first, ahead of goal-based SOLAS amendments. Both DNV and Bureau Veritas put the target entry into force for those amendments at 2032 at the earliest, with work continuing to the next session in March 2027.

What fills the gap today is voluntary. EMSA's guidance on carrying alternative fuel vehicles in RoRo spaces, revised in April 2025, recommends a 20% to 50% state of charge band for electric vehicles, on the reasoning that state of charge directly influences peak heat release rate and that thermal runaway is very unlikely below 30%. Two things about that recommendation are routinely misreported: it sits in the chapter covering car carriers and RoRo cargo ships, not ferries, and it is guidance rather than law. The same document says a vehicle with a damaged or defective battery should have the battery removed or be refused carriage outright, and that onboard charging should not be allowed except to move a flat vehicle out of the way during discharge. It also notes that electric vehicles are on average about 25% heavier than conventional ones, which is a stability and lashing consideration as much as a fire one.

National positions vary and some are notably relaxed. The UK Maritime and Coastguard Agency's guidance states that fires in these vehicles do not release significantly more energy than fires in conventionally fuelled vehicles and are not at greater risk of fire, although such fires may last longer and be more liable to re-ignite. It sets no state of charge limit and leaves vehicle positioning to the operator.

What the fire investigations actually found

The assumption that recent car carrier losses were EV fires does not survive contact with the reports.

• Hoegh Xiamen (2020): improperly disconnected batteries in used conventional vehicles, per the NTSB.
• Grande Costa D'Avorio (2023, Port Newark): two firefighters died. The NTSB's probable cause was the use of a passenger vehicle as a pusher vehicle in an industrial application it was not intended for, causing transmission fluid to overheat, boil over and ignite on a hot engine surface. Not an EV.
• Fremantle Highway (2023): two separate investigations. The Dutch Safety Board's report, published in May 2025, deliberately covers only the emergency response and not the cause. Cause was the Panamanian flag state's remit, and its reported findings, which point to electric vehicles on one deck and to crew being unaware of where EVs were stowed, circulate secondhand rather than as a document you can read.
• Morning Midas (2025): carrying 3,159 vehicles including 65 fully electric and 681 hybrid, abandoned and sunk. The manager said the fire originated in the section carrying electric vehicles, but the cause remains undetermined.
• Felicity Ace (2022): no published investigation report could be located. Treat any confident account of its cause with suspicion.

The honest summary is that battery fires are a real and actively regulated concern, that the industry is moving ahead of the IMO on it, and that the two fatal and total-loss incidents with completed official investigations were both caused by something other than an electric vehicle.

Exporting a used vehicle from the United States

Whichever mode you pick, a used self-propelled vehicle leaving the US carries its own compliance layer, and the rules have been stable for a long time while the citations around them have not.

The 72-hour rule is really two rules. Under 19 CFR 192.2(c), for export by vessel or aircraft the documentation and the vehicle itself must be presented to Customs at least 72 hours before export. For export by rail, highway or under its own power, the documentation goes in 72 hours ahead but the vehicle is presented only at the time of export. Most summaries collapse these into one rule and lose the distinction that matters for anyone booking a sailing.

"Used" is a title test, not a mileage test. 19 CFR 192.1 defines a used vehicle as one whose title has been transferred to an ultimate purchaser, meaning the first buyer who is not a dealer buying to resell. A zero-mile, current-model-year car that has been retailed to a consumer is "used" for export purposes. The definition also covers trucks, buses, motorcycles, motor homes, and self-propelled agricultural and construction equipment, which catches a lot of machinery shippers who assume the rule is about cars.

The document set is the original certificate of title, or a certified copy, plus two complete copies, where "complete" means both sides where anything is written on the back. A lien or a lease does not exempt you; it adds a requirement, namely a separate letter from the lienholder on its own letterhead expressly permitting export. There are exactly three exemptions in the regulation: vehicles entered under an in-bond procedure, under a Temporary Importation Bond, or under a carnet.

The export filing is separate and also runs on 72 hours. Electronic Export Information must be filed for used self-propelled vehicles regardless of value, must always be transmitted predeparture with no postdeparture privilege, and the filing citation must reach Customs at least 72 hours before export. One citation trap is worth knowing: that requirement moved from 15 CFR 30.4(b)(5) to 30.4(b)(4) on 15 September 2025. The substance did not change, but any guide, SOP or filing instruction still citing (b)(5) is visibly out of date, and at the time of writing CBP's own public FAQ page still cites the dead paragraph.

Check the destination clock before you ship

Import rules at the far end are where vehicle shipments most often come unstuck, and the US is a good illustration of why, because it runs two different age clocks administered by two different agencies:

• NHTSA: 25 years. A motor vehicle at least 25 years old is outside the federal safety standards, under 49 U.S.C. 30112(b)(9) and 49 CFR 591.5(i), declared in Box 1 of the HS-7 form. Neither the statute nor the regulation says how the 25 years is measured; counting from the date of manufacture is NHTSA's administrative practice rather than something written into the text.
• EPA: 21 years, and the arithmetic is written down. 40 CFR 85.1502 defines the age as the calendar year of import minus the calendar year of production, and 40 CFR 85.1511(f) grants relief above twenty such years, which is why the form says 21. Note the regulation is 85.1511, not 85.1512, which is a different provision about catalyst-equipped vehicles and is one of the most commonly miscited rules in this area.
• Only one of them cares whether the car is original. EPA's exemption requires "original unmodified configuration" and replacement engines generally disqualify it. NHTSA's 25-year exemption carries no such condition. So a 22-year-old car is EPA-clear and NHTSA-blocked, while a heavily modified 30-year-old car is the reverse.

Other markets differ far more sharply than most shippers expect, and several ban what people assume is merely restricted. The Philippines prohibits right-hand-drive vehicles outright by statute, with narrow exceptions for pre-1960 vintage cars and sanctioned motorsport, and separately bans most used vehicle imports rather than age-limiting them. Chile permits only unused vehicles, with a carve-out for historic vehicles of fifty years or more. Several African markets run mandatory pre-shipment inspection with age limits measured from first registration rather than manufacture. These regimes change, so confirm the current rule with the destination regulator or a customs broker in that market before the vehicle moves, not after it lands.

Choosing between them

Work through it in this order:

1. Measure the piece, including the door. If it clears 2,597 mm wide and high and weighs under about 28 tonnes, a 40ft high cube is in play and is usually the cheapest enclosed option.
2. If it is over height but under 44 tonnes, compare a flatrack or open top against a RoRo booking. You are comparing a per-box rate plus an OOG charge against a W/M rate.
3. If it rolls, is over 44 tonnes, or is genuinely large, RoRo is usually both cheaper and lower risk, because you avoid crane lifts entirely.
4. Check frequency, not just rate. RoRo services are thinner than container services on most lanes, and a cheaper sailing three weeks later is not always cheaper.
5. Confirm the dangerous goods position for your specific mode, especially for anything battery powered, because as above the answer differs between a RoRo deck and a container.

One myth to retire: that RoRo means your cargo sits exposed to weather and salt. On modern tonnage the cargo decks are enclosed, and carriers market them as fully weatherproof. The real exception is the weather deck, which is exactly why the 2026 SOLAS amendments added detection and water monitors there.

Whichever mode you choose, insure it properly. Vehicles and machinery are high-value, easily damaged and awkward to survey after a loss, so read our guide on how much cargo insurance to buy before booking.

RoRo and heavy-lift capability is specialist, and not every forwarder has it. You can filter more than 29,300 logistics companies by country and service in the CargoLinked directory, or post your shipment with the dimensions and weight and let forwarders who handle rolling and out-of-gauge cargo quote on it.