Franchise dealers enjoyed their strongest April for used-car sales in five years, according to CNW Research. Meanwhile, independent dealers saw an increase greater than 17 percent on a year-over-year basis. Franchise dealers sold 1.32 million used vehicles, which is 10.7 percent stronger than April 2010 figures, CNW’s Art Spinella reported. Used sales for independent dealers reached 1.33 million units, up from 1.13 million vehicles a year ago.