I raced for almost three years before I could drive. I usually got a ride with a teammate, a Veteran 35+ rider (as Masters were called back then). He was kind of like the Den Mother of the team - me and one to three other Juniors would pile into his car and go.
Sometimes my mom would drive me. Sometimes a teammate's dad would drive us.
If you're not 18 yet then you MUST have your parent (or whoever takes care of you) sign a release. You'll probably have to either mail it or something. You cannot have just anyone sign it. Back in the day I didn't know that so my older teammates would sign the parent line. You really must have a parent sign it. Back in the day there were no personal computers, no internet, so I mailed my waiver and my mom wrote a check. This made it clear that the parental signature was valid.
Also you should make sure the emergency contact info is pertinent and valid. If you're on the ground severely concussed and they're transporting you to a hospital, what number should they call? Where will they get your insurance info? Who will come to the hospital to drive you home?
Best bet is to have a parent drive you.
If you're not a minor and you just don't have a car, all that still applies, minus the parent stuff. I just had a long talk about how racers think that the waiver is just a formality. Well, it is, until you crash. Then it becomes a legal document, and that scribble you put down will make it impossible for the officials to contact anyone worth contacting.