General Rule For Expungement!! Criminal Records, Expungement

Hello all,

I was curious at what is the general rule or guidelines for getting a previous traffic ticket (speeding) expunged?

Do I need a lawyer to do this?

Do all states allow this?

Can I do this with a recent ticket or do they have to be a certain "age"?

Doing research paper for school and can't seem to find what I want on the internet.

Thanks in advanced to anyone who responds.

- Justin