Insurance “stacking” refers to combining the limits of more than one insurance policy or more than one coverage so that the total available exceeds any single policy’s limit. In commercial trucking cases, coverage is frequently layered, with a primary liability policy, one or more excess or umbrella policies, and additional coverages such as uninsured and underinsured motorist protection. Georgia law addresses stacking in different ways depending on which type of coverage is involved.
Stacking of uninsured and underinsured motorist coverage
The clearest body of Georgia stacking law concerns uninsured motorist coverage, which is governed by O.C.G.A. 33-7-11. In Georgia, uninsured motorist coverage also functions as underinsured motorist coverage, applying when an at fault driver has some liability insurance but not enough to cover the loss.
Georgia recognizes two basic forms of this coverage. One is traditional, also called reduced or non-stacked coverage. The other is excess, also called add-on or stacked coverage. With excess or add-on coverage, the policyholder may collect the limits of the uninsured motorist coverage in addition to whatever is recovered from the at fault driver’s liability insurer, rather than having the uninsured motorist coverage reduced by what the at fault driver pays.
A 1980 amendment to Georgia’s definition of an uninsured motor vehicle made it possible for an insured to stack multiple policies of uninsured motorist coverage when the at fault driver is minimally insured. In 2009, the legislature amended O.C.G.A. 33-7-11 to require insurers to offer add-on, that is, stacking, uninsured motorist coverage, unless the insured rejects it in writing. As a result, add-on coverage is generally the default in Georgia, and an insured who wants the traditional reduced form must affirmatively opt for it. Where an injured person is covered as an insured under more than one applicable uninsured motorist policy, the add-on framework can allow those layers to be combined, subject to the terms of each policy and the priority rules that determine the order in which policies respond.
Layered liability coverage in trucking cases
Liability coverage, the insurance that pays for harm a negligent trucking defendant causes to others, works differently from uninsured motorist coverage. A commercial trucking operation often carries a primary liability policy with a substantial limit, plus one or more excess or umbrella policies that sit above the primary layer.
These layers are not “stacked” in the sense that uninsured motorist coverage can be stacked. Instead, they operate in a defined sequence. The primary policy responds first, up to its limit. An excess or umbrella policy then responds for amounts above the primary limit, up to the excess policy’s own limit, and so on up the tower. Each policy’s contribution is governed by its own terms, including its attachment point, the layer at which it begins to pay, and conditions about exhaustion of underlying coverage. The total available is the sum of the layers, but each layer pays in turn rather than all at once. Disputes in this setting often concern whether the underlying layer has been properly exhausted, whether a particular policy’s terms are triggered, and how the excess carrier’s obligations interact with the primary carrier’s duties.
Federal minimum limits and the MCS-90 endorsement
Commercial trucking insurance also operates against a backdrop of federal regulation. Motor carriers operating in interstate commerce must maintain minimum levels of public liability insurance under federal law. To document compliance, many policies carry an endorsement known as the MCS-90.
The MCS-90 endorsement changes how coverage works in an important way. It obligates the insurer to pay a final judgment against the insured motor carrier resulting from negligence in the operation, maintenance, or use of a motor vehicle, up to the federally required minimum limits, even if the underlying policy would otherwise deny coverage because of an exclusion, a technical breach, or a coverage dispute. The endorsement’s purpose is to protect the public from uncompensated losses by creating coverage where the policy alone might provide none. If an insurer pays under the MCS-90 an amount it would not have owed under the policy itself, the endorsement gives the insurer a right of reimbursement against the motor carrier. The MCS-90 is not a form of stacking; it is a separate, federally mandated safety net that functions independently of how the commercial layers are arranged.
Naming the insurer as a party
Georgia trucking litigation has a distinctive procedural feature historically known as the direct action statute, found in the motor carrier provisions of O.C.G.A. Title 40. For many years, this allowed an injured person to name a motor carrier’s liability insurer as a defendant in the lawsuit. That changed with Senate Bill 426, signed in 2024 and effective July 1, 2024, which applies to causes of action accruing on or after that date. Under the amended law, an insurer may be named as a defendant in a trucking case only in narrow circumstances: when a motor carrier is insolvent or bankrupt, or when personal service cannot be effected on the driver or motor carrier after reasonable diligence. This change affects who appears as a named party, but it does not by itself change the amount or layering of the coverage that is available to satisfy a judgment.
How disputes are resolved
When the parties disagree about how multiple policies apply, the dispute is typically resolved by interpreting each policy as a contract under Georgia law and applying the relevant statutes. Courts examine the language of each policy, the statutory requirements of O.C.G.A. 33-7-11 for uninsured motorist coverage, any applicable rejection of add-on coverage, the attachment and exhaustion terms of excess layers, and the effect of any MCS-90 endorsement. Coverage questions are sometimes addressed through a declaratory judgment action, in which a court determines the rights and obligations of the parties under the policies before or alongside the underlying injury case.
Summary
Georgia law treats stacking differently depending on the coverage. Uninsured and underinsured motorist coverage under O.C.G.A. 33-7-11 can be stacked, with add-on coverage as the statutory default unless rejected in writing, allowing those limits to combine with the at fault driver’s liability coverage. Layered commercial liability policies, by contrast, are not stacked but operate in sequence, with each layer paying in turn according to its own terms. The federally mandated MCS-90 endorsement stands apart, requiring an insurer to satisfy a judgment up to federal minimum limits despite policy exclusions, subject to reimbursement from the carrier. Coverage disputes are resolved by interpreting the policies and statutes together, often through declaratory judgment proceedings.
Disclaimer
This article is provided strictly for general educational and informational purposes. It is intended to explain how Georgia law works as a matter of public legal education, and it does not constitute legal advice, a legal opinion, or a recommendation about any particular course of action. Reading this article, or contacting the website on which it appears, does not create an attorney-client relationship between the reader and any law firm, attorney, or author.
The law changes over time. Statutes, regulations, court rules, and judicial decisions discussed here may have been amended, repealed, superseded, or reinterpreted after the date of publication, and citations to specific code sections or cases reflect the law only as it was understood when this article was written. The application of any legal principle also depends heavily on the specific facts and circumstances of an individual matter, and outcomes vary from case to case.
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