The study, published online ahead of the July print edition of the Journal of Applied Communication Research, found applications at point-of-decision ads at the Michigan Department of Motor Vehicles were almost double -- 25,683 from 13,091 -- those related to multimedia or mass media campaigns.
Study leader Andy King, a doctoral candidate at Purdue University in West Lafayette, Ind., said only about 40 percent of U.S. adults have registered to become organ and tissue donors, while more than 113,000 Americans await organ transplants as of April.
"There continues to be a gap between Americans who state they are favorable to organ donation and those who are actually registered donors," King said in a statement. "There are many reasons people decide not to be donors, but for many people the reason they are not designated donors is because they don't know how to sign up or they don't remember to declare their intent to be donors in situations when they could."
At DMV offices in 34 Michigan counties -- serving 20 percent of Michigan's population -- the study authors placed point-of-decision materials that included posters, stickers and counter cards containing the message: "Tell us now that you want to be an organ donor!"
Notable deaths of 2014 [PHOTOS]