To protect your car and its travelers, visually or physically cast a transparent shield around your car before you set out on any trip. Pro-ject the runic aspects of rad (r) for travel and eolh (z) for divine protection as you cast, saying:

Shield of the Goddess,
surround this car.
Keep us safe in our travels.

Place rue in the front seat of the car to aid in mental alertness, then say:

Herb of the Goddess
keep me physically alert and mentally clear.
Keep us safe always in our travels.

Always bear in mind the basic principle, "As above, so below." That is to say, divine magic needs to be coupled with mundane common sense.