I don't think it really matters, but my first instinct is to say "injured." I think it's from years of hearing lawyer commercials ask: "Have you been injured in a car accident?"

Both are correct, but you would be more likely to hear "injured" in that situation.

I see, wounded is commonly used in battles/a war. In accidents, people are injured. Thanks Mojave!

Mr. Smith was injured in a road accident. Mr. Jones was wounded in the war.

We tend to associate "wounded" with intentional acts like battle, gun shots. etc. "Injured" is used with accidents.