Museum director Willena Adams told a reporter: "We feel bumper stickers are a vital part of 20th century man's legacy.

"There has been as much creativity shown in making bumper stickers as in some best-selling novels."

Favourites on the California freeways at present include:

Hire the Morally Handicapped

Keep American Clean - eat a pigeon

Dirty Old Men Need Love Too

Honk if you Love Jesus

Apple Pie Makes you Sterile

POWs Never Have a Nice Day

What Sort of Day You Have is No Business of Mine

During the 1964 election campaigns, the Aldine printing company in Los Angeles turned out 25 million stickers with hard political messages.

Ron