Rolling Advertising Network, Dallas, has been established to offer 35,000 over-the-road trailers as an advertising medium. Advertisers or agencies can buy one or more of 12 geographic regions, including four in Canada. Boards are 6 to 12 feet high and 18 to 20 feet long. Jose Avila, general manager, said "One tractor-trailer with a billboard mounted on each side will deliver a minimum of 8.5 million advertising impressions per year. The cost is only a few cents per thousand impressions."