Customers weren't concerned with safety, but that doesn't tell us why they were safer on the roads after buying the new car. If anything, this undermines the possibility that buyers started driving better.

We’re not interested in what the company could do. We’re interested in how this car somehow improved customers' road safety despite in fact being less safe than other cars.

If customers were unaware that the car was relatively unsafe, then we have no reason to believe they would start to drive more carefully. This doesn’t resolve anything.

Why would having two cars in their household make someone safer on the road? This doesn’t resolve the paradox that driving a relatively unsafe car made these customers safer.

Even though the car in question is unsafe compared to other cars, it’s a big step up safety-wise from bicycles and motorcycles. Hence, customers—who previously rode bicycles or motorcycles—became safer on the roads once they bought the new car.