Making safety part of our consciousness is hardly nothing. He let us know we didn't have to just accept anything Detroit had to offer. When manufacturers are all doing the same thing, where's the choice? Look what they did to Tucker when he tried to change the way cars were made.
Was I unclear? Nader did nothing to make anything safer, he made up stories to scare people, and capitalized on that fear to make a name for himself. If you think that raises awareness about safety you are more than welcome to your opinion, I think it actually makes people less concerned about it because they end up thinking that other people are protecting them from stupid dangers.