I saw this during a television commercial.

Problem:
The “If” clause should have been written in the past subjunctive mood.

Explanation:
The TV commercial was on the Discovery Health channel.

“Could You Survive?” is the title of the show that was being advertised.

The premise of the show is to ask viewers whether they would be prepared to survive in the event of a disaster or other emergency.

The complete sentence that I saw was along the lines of “If your husband was trapped in a car, would you be able to rescue him?”

The problem with this sentence is that “was” is the wrong form of the verb “be” to use in the if-clause.

The if-clause is a subordinate clause — also called a “protasis” — in this conditional sentence.

A conditional sentence discusses one of the following:

• a factual implication, as in “If you cool water to 0 degrees Celsius, it freezes.”;
• a hypothetical situation, as in “If you were king, would you make me a knight?”

If the hypothetical situation is described with a contrary-to-fact present conditional, then the past subjunctive must be used.

In other words, as noted at Wikipedia, the past subjunctive is used after the conjunction if to express hypotheses.

It is a common English blunder to use simply the past tense, and that is the blunder made by the TV ad writer.

Solution:
“If your husband were trapped in a car, would …”