I have some future car rental reservations with Dollar, and I've read that it's a good thing to sign up for their "Fastlane" service which supposedly allows you to avoid long lines at the rental desk.

When I went to their website to sign up, they want all your personal information, including drivers license and credit card. I'm a little uncomfortable with giving this information in advance. I'm just concerned in case I cancel a reservation. Has anyone used this service, and what are your thoughts about providing this information. Is it worth the benefits? Thanks.

I am a fastlane member. The whole point is, that you give this info ahead of time so that when you get there, you don't go to the desk and give them your cc#, DL# etc. You just pick a car and they hand you the paperwork at the gate, it's already filled out with all of your info. If this makes you uncomfortable, then it's probably not worth the benefit.

Yes, and I may be one of the voices you're quoting as recommending joining Fastlane.
Yes you need to provide the license and credit card information. One of the ways they speed up the rental process is that they already have all that information in the system. I'm not sure what there is to worry about with providing the information. Dollar is a secure site and a trusted company. Even if somehow they tried to charge you for something you didn't get, one call should easily clear up that -- but I've never heard of that happening.
If you cancel a reservation, be sure to get and keep the cancelation number. In checking, making, and changing three different Dollar reservations for our recent California trip, I think I ended up cancelling at least a dozen reservation. I put the computer print out of the reservation with the cancellation number clearly written across the top in a special file in my drawer. I've never had a problem with them charging, and if I did, I could provide them with the cancellation number and get it credited.
Bypassing an hour long line at the San Francisco airport and an even bigger one at Los Angeles to get in the quick Fastlane made me realize that joining Fastlane was one of the smartest things I've done.

Thanks Loki & Patrick for your helpful reponses. I've been away from the computer and haven't had a chance to thank you. It was just the info I was looking for, and I went ahead and signed up.

Good. And you should be receiving a couple of free upgrade certificates along with your membership card.

Thought I'd follow up now that we're back.

Not sure that the Fastlane program really worked for us. We were renting at their Phoenix Sky Harbor location, and after taking the shuttle to their site, we were told we still had to wait in line, but it would be a faster line. No so. There were 2 lines: Regular & Fastlane. Guess which one was longer! Yup, it was Fastlane. Although it did move a little faster, so it was a toss-up. We also didn't get to use our upgrade coupon. We had reserved an intermediate, and were hoping for an upgrade to full size, but the agent said they were out of everything except for a neon blue PT cruiser which didn't interest us. Oh well. But we were still happy because everything else went smoothly, including the return.

Sorry, that longer line was probably my fault. I KNEW I should stop telling everybody to get Fastlane!

Aha! That explains why everyone on line was mumbling "Patrick sent me."