Pennsylvania asks drivers to make two decisions most states do not. The first is the tort election. The second is stacking — and it decides how much coverage you actually have when someone with no insurance drives into you.
The coverage this applies to
Stacking concerns uninsured and underinsured motorist benefits: the coverage that pays when the at-fault driver has no insurance, or carries too little to cover what they did.
That is not a remote scenario. Pennsylvania’s minimum liability is 15/30/5, which means a driver can be entirely legal while carrying $15,000 for your injuries. A serious injury exhausts that in an afternoon, and the rest falls to your own underinsured coverage.

Stacking does not multiply your liability limits. It applies to the coverage protecting you, not the coverage protecting other people from you. Those are separate lines on the policy.
How stacking works
Where more than one vehicle is insured, the stated uninsured or underinsured limit applies separately to each vehicle, and the limits available are the sum of those amounts.
| Vehicles insured | UM/UIM limit each | Unstacked available | Stacked available |
|---|---|---|---|
| 1 | $50,000 | $50,000 | $50,000 |
| 2 | $50,000 | $50,000 | $100,000 |
| 3 | $50,000 | $50,000 | $150,000 |
| 4 | $100,000 | $100,000 | $400,000 |

The pattern is straightforward: unstacked gives you the limit on the vehicle you were in. Stacked gives you every vehicle’s limit added together, regardless of which one you happened to be driving.
Waiving it
Stacking is the default position. A named insured may reject it, and doing so lowers the premium — which is why a great many Pennsylvania policies are unstacked without the household ever discussing it.
The waiver is not casual. Pennsylvania prescribes what the form must tell you: that by signing, you are rejecting stacked limits under which coverage would be the sum of the limits for each vehicle; that the limits are instead reduced to those stated in the policy; that you are doing so knowingly and voluntarily; and that your premium will be reduced.

The waiver must be signed by the first named insured and dated. Pennsylvania is explicit that a rejection form which does not comply is void — which means the stacked coverage remains in force despite the attempted rejection. Defective waivers are litigated regularly, and they are worth knowing about.
What the trade actually is
Waiving stacking reduces the premium. How much depends on the carrier, the number of vehicles, and the limits, but it is a real saving.
| Household | Leans toward |
|---|---|
| Two or more vehicles insured together | Stacked — the limits genuinely multiply |
| Teenage or new drivers in the house | Stacked |
| Long commutes, heavy highway mileage | Stacked |
| A single vehicle on the policy | Difference is small either way |
| Very tight budget, low mileage, strong health cover | Unstacked is defensible |

The Lehigh Valley context matters here for the same reason it does with the tort election. Route 22, Interstate 78 and the New Jersey border all put local drivers alongside a lot of vehicles whose coverage they know nothing about.
Where the money actually comes from
It helps to see the order in which a serious claim gets paid. The at-fault driver’s liability coverage pays first, up to their limit. When that runs out and the injuries have not, your own underinsured motorist coverage takes over.
That second layer is the one stacking multiplies. A household carrying $50,000 across two vehicles has $100,000 available stacked, against $50,000 unstacked — on exactly the same policy, for a premium difference measured in tens of dollars a month.
It is also the layer people forget they are buying. Liability protects other people from you, and it is the number drivers tend to shop. Uninsured and underinsured coverage protects you from everyone else, and it rarely gets the same attention.
How this interacts with your tort election
These are separate decisions and they solve different problems. Your tort election decides whether you can claim for pain and suffering at all. Stacking decides how much money is available to pay a claim once you can make one.
A household on limited tort and unstacked coverage has made two cost-saving choices that compound, and most have never consciously made either. Our guide to full tort versus limited tort covers the other half of that pair, including the exceptions that restore your rights.

A change that has been proposed, not passed
Senate Bill 578 of the 2025-2026 session would repeal the stacking provisions and prohibit stacking on new policies. It was introduced in April 2025 and referred to the Banking and Insurance Committee.
As things stand it has not advanced and is not law. Stacking remains a live choice on Pennsylvania policies today. It is worth knowing the proposal exists, and worth ignoring any article that describes it as settled.
Finding out what you have
Your declarations page names it. Look for uninsured and underinsured motorist coverage and the words stacked or unstacked alongside the limits.

If you cannot find it, or the page is ambiguous, bring it in. We read declarations pages with customers as a matter of routine through our insurance service in Bethlehem, and we will price both options across several carriers so the trade is a decision rather than a default. For the coverages you are legally required to carry, see Pennsylvania’s minimum requirements.
For neutral background on how uninsured motorist coverage works generally, the Insurance Information Institute publishes an overview.
Frequently asked questions
What does stacked coverage mean in Pennsylvania?
When more than one vehicle is insured, stacking means the uninsured and underinsured motorist limits apply separately to each vehicle and are added together. Two cars with $50,000 limits give $100,000 of stacked coverage.
Can I refuse stacking in PA?
Yes. A named insured may waive stacking, in which case the limits available are simply the stated limits for the vehicle involved. The premium is reduced when you do.
What makes a stacking waiver valid?
The waiver form must be signed by the first named insured and dated. Pennsylvania is explicit that a rejection form which does not comply is void — meaning the stacked coverage remains in force despite the attempted waiver.
Does stacking apply to liability coverage?
No. Stacking under Pennsylvania law concerns uninsured and underinsured motorist benefits — the coverage that protects you when the at-fault driver has no insurance or not enough. It does not multiply your liability limits.
Is stacking worth it if I only insure one car?
The benefit is much smaller, since there is only one set of limits on the policy. It matters most for households insuring two or more vehicles, where the limits genuinely multiply.
Is Pennsylvania changing the stacking rules?
A bill to prohibit stacking on new policies, Senate Bill 578 of the 2025-2026 session, was introduced in April 2025 and referred to the Banking and Insurance Committee. As things stand it has not advanced and is not law, so stacking remains a live choice.
Insuring more than one car?
Then stacking is worth five minutes of your time. Bring your declarations page and we will show you both numbers side by side. Hablamos Español.



































