Carrier is safer for the both of you. When you open the door for a pitstop, you won't have to worry about poor kitty running off into traffic or who knows where. (My Mom and Brother once spent 2 days parked alongside the Alcan in the middle of nowhere trying to find their baby -- they did).

Also, it will be more pleasant for you. Halo is notorious for peeing when she's frightened. Being soaked with stinky kitty urine is not a pleasant experience.

We love our Nylabone fold-away carrier. It's hard plastic and has plenty of room. It can be used for airline travel. And the best thing is that when you unlatch the sides, it collapses flat so that it can be stored away. Petco.com has several sizes and they just happen to be on sale right now on their website.