Last year, Star Wars creator George Lucas allowed the Monmouthshire safety campaign to use the slogan "Car Wars".
This helped cut accidents with 98 fewer people injured on the roads.
Council official, Gillian Morgan said: "Tolkien wrote his books for his children. I'm sure he would have appreciated the campaign."
But a spokesman for Tolkien's family said: "It's not our policy to lend Tolkien's name to public campaigns."