Because I believe it’s a small way to witness to the Gospel. it reminds people in an increasingly secular society of prayer and faith. Who knows, maybe it has a bigger impact than I know?
I am always encouraged when I see other drivers who have a rosary on their mirror, or a pro-life sticker on the bumper. It’s nice to know there are some other catholics out there.
It also reminds me to pray.
On a different level, I like to think Our Lady watches over me while I’m driving.
And as well, if I ever got in a serious accident, perhaps a first responder would see them and call for a priest to administer the last rites.