I agree it can be good, but it's not the best place for me. I believe it is beneficial to pray alone, where you won't be interupted. A car can work for that. I also believe that a prayer does not have to be closed eyes, folded arms, on your knees, etc. (though I do think it is the best). A prayer can be "God help me get through this." For example, if there was a bad wreck on the road and you need to get somewhere, you can call out to God for help. Prayers don't have to be big and fancy.
H-D 