That depends on how low the fog is. If it's ground fog, use the low beam; if it's a high fog use high beam. Driving tip in fog: Wear your sun glasses, you'll be surprized how they cut thru the fog.
Jerry Howarth
I grew up in Perry Iowa, graduated in "57" attended a Bible ollege in Omaha Neb., earned a Th.B degree from Bethany Bible College & Seminary, Dothan, Al. Pastored 5 different Baptist Churches over a period of 38 years; still Pastoring a small non-denomination congregation in my retirement years. Have published two books; one a self-help book and a book of poetry and am currently writing another book about the Good Hand of God. Have been married to same sweet heart for over 50 years to whom God blessed us with 4 super kids and 15 wonderful grankids two of which are romping around in God's quadzillion acres of Glory.