I think I saw this girl I used to knew / liked back in college?
so the other day when i was driving around town with my friends so i was waiting for the red light to turn green & the other cars from the other street were driving by & i saw this red car driving by & i saw someone looking at me while driving by & idk i think it was this girl who i knew in school& i had a crush on her & i havent seen her ever since i finish college but idk i might be imaging things lol.
I think in general whenever we're interested in someone romantically we tend to "see" them around a lot more. Vast majority of the time it isn't that person. Usually you'll realize within a second or two that some feature of the person reminded you of them and that's all. And even in those moments where you are left wondering if you actually saw her, there's often things that don't add up, like why they would even be where you saw them.
I'm not sure quite what you're asking for advice on, but know that this happens to everyone. And maybe this experience can help to teach you more about taking action and taking chances on people when you still had the chance. You obviously wish you had kept in touch with this crush, but in most cases you'll lose contact with less significant people in your life.
I wouldn't stalk the town looking for this girl, but if you think there's a good chance it was her, then there's a possibility that she still lives nearby and will travel through that spot again one of these days. But you have to ask yourself how likely it is that this crush was looking at you during a chance passing at a traffic light.