Your client is broadsided by a tractor with no trailer attached. The driver is an owner-operator leased to a motor carrier, and within a week you have two adjusters denying each other's coverage. The carrier's insurer says the tractor was operated outside the carrier's business, so its primary auto liability does not respond. The owner-operator's bobtail carrier says the driver was still under dispatch, so non-trucking use is excluded. Both are pointing at the other, and your client is caught in the seam. That seam is where most of the money lives in leased-carrier cases, and the attorney who works it first usually controls the settlement.
The recurring dispute over bobtail insurance coverage is not really about the tractor. It is about a single factual question: at the moment of impact, was the driver in the business of the motor carrier? Everything downstream, which policy triggers and whose balance sheet is exposed, flows from that answer.
Two Policies Pointing in Opposite Directions
The motor carrier's primary auto liability is the deep pocket. It carries the filed limits the Federal Motor Carrier Safety Administration requires, and it typically includes an MCS-90 endorsement. The MCS-90 is a suretyship-style guarantee that the insurer will pay a judgment for public-highway injuries up to the filed amount even when a policy exclusion would otherwise bar coverage. It follows the truck while it is under dispatch or hauling for the carrier. That is the policy you want responding.
Bobtail and non-trucking-use (NTU) policies are the mirror image. They are purchased by the owner-operator to cover the tractor when it is operated without a trailer or outside the carrier's business, precisely the situations the carrier's primary policy excludes. NTU limits are usually thin, and the whole point of the coverage is to fill gaps, not to stand in for a carrier's filed liability. When defense counsel labels a loss "non-trucking use," they are trying to shove your recovery from the filed-limit policy into the low-limit one.
Bobtail Versus NTU
Practitioners use the terms loosely, but there is a distinction worth keeping straight. "Bobtail" describes a physical condition: the tractor running without a trailer. "Non-trucking use" describes a business condition: the tractor operated while not in the carrier's service. A tractor can be bobtailing while still in the carrier's business, for example deadheading empty to pick up an assigned load. That overlap is exactly why the coverage fight is so common.
The "In the Business of the Carrier" Question
The whole case turns on where the driver was and why. Courts and adjusters recur to the same fact patterns:
- Deadheading empty to pick up a dispatched load. Most authorities treat this as being in the carrier's business, which points to the primary policy.
- Driving home after dropping a trailer with no further dispatch. This looks more like personal use, favoring the NTU insurer's argument.
- Running a personal errand between loads while under a lease. Genuinely contested, and heavily fact-dependent.
- Repositioning the tractor for maintenance the lease requires. Often argued as carrier business because the lease compels it.
Do not accept the label the first adjuster gives you. "He was going home, so it is non-trucking use" is a conclusion, not a fact. The facts are the trip, the dispatch status, the driver's duty status, and what the lease required of him at that moment.
Why 49 CFR Part 376 Can Override the NTU Label
Here is the doctrine that defense counsel hopes you forget. Under the federal leasing regulations at 49 CFR Part 376, a lease between an authorized carrier and an owner-operator must give the carrier "exclusive possession, control, and use" of the equipment for the duration of the lease, and the carrier must assume complete responsibility for its operation. Courts have long read this exclusive-possession-and-control language to make the carrier vicariously liable for the leased equipment regardless of a private coverage label like "non-trucking use."
The point is that the federal regulatory relationship does not switch off every time the trailer comes off. Many courts hold that once a lease is in effect and has not been formally terminated in the manner the regulation requires, the carrier's statutory responsibility can attach even during a bobtail movement. An NTU endorsement is a private contract between the owner-operator and his own insurer. It does not rewrite the carrier's obligations to the public under Part 376. When you brief the coverage question, lead with the regulation, not with the endorsement.
The NTU label describes a private insurance contract. The carrier's duty under the federal leasing rule describes the public's protection. The first does not erase the second.
The Discovery That Resolves It
You do not win this argument with rhetoric. You win it with documents that fix the driver's status at the moment of the crash. Build the request list before the first status conference.
The Lease Agreement First
Get the full independent-contractor lease, every addendum, and the settlement statements. Read it for the Part 376 exclusive-possession-and-control language, the term, and the termination provisions. A lease that was never formally terminated in writing is a lease still in force, and that fact alone can defeat a non-trucking-use defense. Check who was responsible for insurance, maintenance, and fuel, because those allocations tell you whose business the driver served.
Then layer in the operational records that pin the trip:
- Dispatch and trip records showing whether a load was assigned or pending at impact.
- Electronic logging device (ELD) duty-status data, which tells you whether the driver was on-duty driving, on-duty not driving, or off-duty when it happened.
- Fuel receipts and fuel-card data placing the tractor on a route consistent with carrier business rather than a personal detour.
- The carrier's Qualcomm or telematics messages, gate logs, and any bill of lading tied to the movement.
ELD data is the quiet workhorse here. A duty status of on-duty driving with a pending dispatch is hard to reconcile with a pure personal-errand theory, and it tends to move the loss back onto the filed-limit policy where it belongs.
Working the File
Treat the coverage question as a liability question from day one. Tender to both insurers, demand the declarations pages and the MCS-90, and put the lease and dispatch records at the top of your discovery. If the carrier's insurer denies on a non-trucking-use theory, your Part 376 argument and your ELD data are the rebuttal that opens the filed limits. For related mechanics on trailer-detachment fact patterns, our ongoing coverage in truck and motorcycle litigation tracks how these disputes play out. When the coverage fight bleeds into competing insurer claims on the recovery, the analysis in liens and settlement is worth a look, and the doctrinal trends are collected under case law and settlements. Nail the business question early, and the deep pocket usually shows up on its own.