FreightWaves Ratings cuts through the noise of freight technology product reviews to make you a smarter buyer

Tractor fuel vs reefer fuel: What’s the difference?

Tractor fuel and reefer fuel can both be used in trucks and heavy equipment. However, there is one key difference: reefer fuel cannot be used on vehicles that will ever be driven on public roads. 

However, there is one notable exception. Refrigerated trailers, also called reefer trailers, are driven on-road. However, the reefer fuel is not used to power the truck. It is only used to maintain the refrigeration. 

Here’s everything you need to know about tractor fuel vs reefer fuel, so you can avoid making costly mistakes.  

What is tractor fuel?

Tractor fuel is a type of diesel adapted to local climate conditions. In the early and mid-20th century, tractor fuel was a type of low-grade diesel similar to kerosene. Now, it is also called number two diesel and is somewhere between gasoline and diesel in the distillation of crude oil. 

Tractors, trucks, semis, and many construction vehicles can use tractor fuel. Vehicles using tractor fuel can be driven on public roads. However, it is more expensive than reefer fuel as it is subject to road tax. 

But how much is tractor fuel? The prices fluctuates with supply and demand, and is heavily dependent on state taxes.

What is reefer fuel?

Reefer fuel, also known as refrigerated fuel, refers to the diesel fuel used to power refrigeration units on refrigerated shipping containers, trucks, and trailers. Legally, it can’t be used to power the truck itself.

It is, however, allowed for use in off-road vehicles, and is dyed red to clearly distinguish it from standard diesel. Because vehicles that use reefer fuel do not use highways or public roads, it is not subject to road tax. This makes it a cost-effective solution for farm or construction vehicles that operate on private property.

The key characteristics of reefer fuel are:

  • It has a lower viscosity compared to standard diesel to improve flow at low temperatures. This allows the fuel to continue flowing even in very cold conditions to power refrigeration units.
  • It contains additives to prevent gelling. Standard diesel fuel can gel and clog filters when exposed to cold temperatures. Reefer fuel additives lower the temperature at which gelling occurs.
  • It has improved stability and oxidation resistance. Reefer units undergo frequent cooling/heating cycles, which can increase oxidation and breakdown of the fuel. Reefer fuel is more stable to withstand this.
  • It meets low-sulfur specifications. Emissions standards for non-road diesel engines powering refrigerated containers and trucks mandate the use of low-sulfur diesel.
  • It may contain lubricity additives. The constant cooling/heating cycles can cause increased wear and tear. Some reefer fuels have additives to improve lubricity.

The goal of reefer fuel is to maintain proper fuel flow and combustion even under cold and cycling conditions to ensure reliable operation of refrigerated transport equipment. It is essentially a specialized cold-climate diesel formulation. That’s because if the trucks are driven on the road, the company could face fines.

Tractor fuel vs reefer fuel

Which fuel should you choose? That depends on the vehicle you’re using and its intended purpose.


Reefer fuel can be used to maintain the temperature in refrigerated trucks, commonly called reefer trucks. However, it cannot be used to fuel the actual truck’s engine.

Reefer fuel can also be used in agricultural or farm equipment that will never be driven on a public road. For example, on large development projects or farms work vehicles can use reefer fuel. 

Tractor fuel, in contrast, is also a standard number two diesel. But tractor fuel can be used in any vehicle that takes diesel. There are no penalties for driving vehicles with tractor fuel on public roads. 

For vehicle type, there are just two questions to ask. First, can the vehicle take standard number two diesel? And second, will it need to ever drive on a public road? If the answer to both is “yes,” then tractor fuel is the best choice. 

Cost and usage

The major reason to choose reefer fuel instead of tractor fuel is to save on cost per gallon. Without road tax added, reefer fuel’s price is lower everywhere, especially in states like California with high road taxes. 

According to the U.S. Department of Energy, an idling truck burns about 0.8 gallons of diesel per hour. Trucks burn an average of 1,500 gallons of fuel while idling per year. 

Over the course of a year, off road vehicles could save an average of $3,870 by using reefer fuel. And that is just idle time! If you use 3,000 gallons of fuel a year, that is a savings of $7,740 per year, as long as the vehicle doesn’t drive on a road. 

Potential fines

Keep in mind that it is easy for government officials to see when it is used on the road. The bright red dye makes it stand out. 

Officials use a black light to detect dye residue in the fuel tank or major engine parts. The cost of being caught can be up to $10,000 in some states, which should seriously deter you from taking the risk. It’s not worth it.  


As most people know, normal fuel is taxed by the government. These taxes are used for road maintenance, rest stops, and other services provided by the Federal Highway Administration. 

Both gasoline or diesel are taxed for all types of vehicles. However, since reefer fuel is an off road diesel it is not taxed. If you try to use vehicles with reefer fuel on the road, you will be fined for illegally using these vehicles  on the road and evading road taxes.  

Know your fuel purpose

What is tractor fuel vs reefer fuel? In summary, they are similar on a chemical level, and they can be used in the same types of vehicles, though they serve different purposes. Reefer fuel can only be used in off-road vehicles or for the purpose of maintaining refrigeration in reefer trailers. Tractor fuel can be used in any vehicle that can take standard number two diesel. All in all, it’s important to understand how they’re different so that you don’t accidentally use one when you should opt for the other! .


Is reefer fuel the same as diesel?

Chemically, reefer fuel is similar to diesel. However, it is not the same as diesel because it can only be used on private property. It is dyed red to prevent misuse or confusion in its intended purpose. It can be used to maintain refrigeration in reefer vehicles, but not to power the truck.

Can you run off-road diesel in a reefer trailer?

You can use off-road diesel or reefer fuel in a reefer trailer, as long as the fuel is not used to propel the vehicle on the road. Reefer fuel or low emission diesel are often used to maintain temperature controls in reefer trailers. 

How long does reefer fuel last?

Reefer fuel used to maintain refrigeration in a reefer trailer usually lasts three to five days. How long the fuel lasts will depend on the climate, how often the trailer is opened, and the size of the fuel tank. 

Sign up for a FreightWaves e-newsletter to stay informed of all news and trends impacting supply chain careers and operations.

Put the brakes on fleet fuel overspending

Stay in control of your fleet with Fuelman's fuel cards. Manage your account on the DRIVEN FOR FUELMAN ™ app 24/7, track driver purchases, and get easy-to-understand reports - all while enjoying savings at the pump.