That's not quite the same situation as the NSA aren't just looking at people who are involved in a terrorist attack, but instead data-mining everyone. If the police were checking phone records of everyone driving, regardless of whether they were involved in a crash, then your analogy would be better.
I'm no fan of the modern lack of privacy and I definitely believe that freedom should trump security. However, if someone is in a crash, then there is a good reason to investigate further and the specific phone records are a reasonable infringement of privacy.