If you are injured by a product that was built exactly the way the manufacturer intended, you might still have a valid claim. This is different from a manufacturing defect, where a single item comes off the line faulty. A design defect means the entire product line is dangerously flawed from the blueprint stage. Every unit of that product carries the same risk. To win a design defect case, you need to show that the product’s design itself is unreasonably dangerous. Courts use two main tests to decide that question: the consumer expectation test and the risk-utility test. Understanding these tests helps you know what evidence you need and what a jury will be asked to weigh.
The consumer expectation test is the simpler of the two. It asks whether the product performed in a way that an ordinary user would reasonably expect. If you buy a coffee mug, you expect to be able to hold it without the handle snapping off when you lift it. If the handle is designed so thin that it breaks under normal use, the design fails the consumer expectation test. The idea is that a product should meet the basic, common-sense safety assumptions of the people who buy it. This test works best for simple products where anyone can judge what safe performance looks like. A blender blade that shatters on the first use is clearly not what anyone expects. But the test becomes harder to apply when the product is complex. For example, what does the average person expect from the braking system on a motorcycle? Most people do not have enough technical knowledge to form a reasonable expectation about how much stopping distance is safe. In those cases, the court may turn to the risk-utility test.
The risk-utility test is more analytical. It balances the dangers of the product’s design against the benefits it provides. A jury will consider factors like how serious the potential injuries are, how often the design causes harm, whether a safer alternative design exists, and what that alternative would cost. The basic question is whether the design’s risks outweigh its usefulness. If a car’s fuel tank is placed in a location that makes it likely to explode in a rear-end collision, but the manufacturer could have moved it to a safer spot for only a small increase in cost, the design likely fails the risk-utility test. Even if the car otherwise performs well, the danger is not worth the trade-off. This test allows experts to testify about engineering possibilities, cost-benefit analysis, and industry standards. It gives the jury a structured way to decide if a product’s design was unreasonably dangerous.
You do not have to prove that the manufacturer intended to hurt anyone. Strict liability applies in most states for design defect claims. That means you only need to show that the product was defective and that the defect caused your injury. You do not have to prove the manufacturer was negligent or knew about the danger. This is a major advantage for injured people. But you still have to bring strong evidence. Your case will likely depend on an expert engineer who can point to the specific flaw in the design and show how a safer alternative existed at the time the product was made. The expert must also explain why that safer design would not have made the product unusable or prohibitively expensive.
The manufacturer will try to argue that the design was reasonable given what was known at the time, that the product met industry standards, or that you misused the product. They may also claim the risk was obvious and you should have known to be careful. The consumer expectation test often neutralizes that last argument: if the ordinary user would not expect the danger, the design is defective regardless of whether it was obvious to an engineer. Under the risk-utility test, even an obvious danger can be unreasonable if the utility of the design is low and the risk is high.
If you are pursuing a design defect claim, your lawyer will gather design documents, internal company communications, and test results. They will look for evidence that the manufacturer knew about the design flaw or failed to adopt a known safer alternative. But even without that knowledge, strict liability means you can still win. The key is to focus on the design itself. Was it unnecessary? Was it dangerous? Could it have been done differently? If the answer to all three is yes, you have a strong case that the product should never have been made in the first place.
