The passengers divide into two teams, left and right, with any odd passenger going to assist the driver's team since the driver should be concentrating on the road.
Each team tries to find the letters of the alphabet, in the correct order, on signs on 'their' side of the road. Multiple letters may be used from one sign as long as they are seen in the correct order. While looking for Q, antique shops and BBQ advertisements are highly valued. As the letters are found they must be called out to let both your team members and your opponents know what you are looking for.
There are many variations of this game such as making it harder for the participants by adding rules such as only the first letter of a word is valid or once a word is used it can't be used by anyone else. There's a rendition for this game in the movie Never Been Thawed (2005) that makes roadkill a wild card.