What is a bobtail truck? A guide for fleet operators

What is a “bobtail” or a bobtail truck?

In the trucking industry, bobtail, bobtail truck, and bobtailing refers to a semi-truck without an attached trailer.

Additionally, the Department of Energy calls a straight truck transporting propane gas a bobtail.

Most truck drivers typically do not like to bobtail. Besides not generating revenue while bobtailing, trucks can become more difficult to drive. Trucks are designed to carry heavy trailers, so when there is none, drivers must be more careful while maneuvering and braking. Despite weighing less, bobtail trucks require a longer braking distance. They are more susceptible to skidding out on tight curves and turns, even with anti-lock brakes.

What is the origin of the word “bobtail?”

Within the trucking industry, there are two popular theories about the origin of the word “bobtail.” Both have to do with animals with shortened tails.

Some believe the term was popularized by the holiday song “Jingle Bells.” There are lyrics in the song saying, “bells on bobtails ring.” This refers to the style of the horse’s tail cut — typically docked or cut short to prevent entangling with the sleigh reins.

The other theory is that the term originated from a breed of cats with short or bobbed tails. Unlike other cat breeds, bobtail cats have a shorter, stubby tail giving them the appearance of a bobcat.

Truckers might think a semi-truck without a trailer looks truncated or cut off, similar to these animals with short tails.

What’s the difference between bobtailing and deadheading?

For fleets, “running bobtail” and “deadheading” are sometimes confused and used interchangeably. However, they refer to two different things.

In the trucking business, bobtailing involves driving a freight-carrying truck without a trailer. This happens when a truck driver is on their way to pick up a loaded trailer for full truckload or less-than-truckload transport. Or, they could be returning to a terminal after unloading their trailer.

Deadheading trucks have a trailer attached, but it’s empty. For example, you’ve probably seen flatbed tractor-trailers driving on roads, transporting nothing on the empty trailer.

Both bobtail and deadheading trucks do not contain freight, so they are not generating revenue, hence the confusion.

What are some of the risks of bobtailing?

Bobtailing, which involves operating a semi-truck without a trailer, presents several unique risks that drivers and other road users should be aware of, such as:

1. Handling and stability issues: Without the weight of a trailer to stabilize the truck, most of the weight is concentrated over the front axle. This makes the steering more sensitive and less predictable, especially at highway speeds and during cornering. Drivers need to adjust to the lighter rear end to maintain control. Furthermore, bobtailing also increases the risk of rollover, which involves a vehicle tipping over and rolling over to its side. The altered center of gravity makes bobtail trucks more prone to rollovers, particularly during sharp turns, quick lane changes, or on uneven roads and exit ramps.

2. Reduced braking efficiency: The braking system in a semi-truck is designed to account for the weight of a loaded trailer, with much of the braking force applied to the rear axles. When bobtailing, there is significantly less weight over the rear axles, leading to reduced traction and braking power. Bobtailing increases stopping distances, making it easier to skid or lose control during sudden braking.

3. Challenges in extreme weather: A lighter truck has less contact with the road surface, leading to reduced traction in rain, snow, or icy conditions. Without the weight of a trailer, bobtail trucks are also more vulnerable to strong winds, which can push them off course or make them difficult to control, especially on open roads or bridges.  

4. Regulatory and Insurance Considerations: Despite not having a trailer, bobtailing operations are still subject to Commercial Driver's License (CDL) requirements based on the truck's Gross Vehicle Weight Rating (GVWR). Your drivers will need the appropriate CDL based on the truck’s specifications:

• Class B CDL: Allows operation of single vehicles with a GVWR greater than 26,000 pounds. No trailers permitted under this class.

• Class A CDL: Required for operating combination vehicles with a GCWR exceeding 26,000 pounds, where the trailer's GVWR is greater than 10,000 pounds.

In addition, specialized "bobtail insurance" or "non-trucking liability" coverage is often necessary to protect the driver and company during bobtail operations. Standard commercial auto insurance policies may not fully cover accidents that occur when the trailer tractor is driven without a dispatched load.

How to improve bobtail safety with Samsara

While bobtail trucks present some dangers while operating on the road, innovative organizations are leveraging innovative fleet safety technology, such as Samsara’s AI Dash Cams, to minimize incidents and reduce operational costs. 

With Samsara, fleets are able to improve safety and liability protection while bobtailing. AI Dash Cams provide real-time monitoring and recording of road conditions and driver behavior, which is essential when operating without a trailer.

UniGroup, a $1.5 billion transportation cooperative that handles one-third of all professional moves in the United States, transformed their safety operations with Samsara AI Dash Cams. Prior to Samsara, tickets and citations were UniGroup’s primary indicators of safety incidents. To gain visibility into their vehicles, UniGroup partnered with Samsara to implement AI Dash Cams across their fleet—their first-ever dash cam deployment. With Samsara's change management support, they secured fast dash cam buy-in among their 4,700 drivers. Using in-cab alerts to reinforce safe driving practices, UniGroup saw a 42% reduction in safety events in just one year. 

“AI Dash Cams had an immediate positive impact on our fleet,” said Melissa Pilgrim, Safety Manager. “Samsara is always there to meet our evolving needs and their continuous innovation helps us stay ahead.”

To learn more about how Samsara can help you improve bobtail safety, check out Samsara’s Video-Based Safety solution and reach out to our team today.