The Savannah College of Art and Design will start using smaller buses on two of its routes through downtown starting March 23. The decision, which a college spokeswoman says will not affect student transportation, comes after meetings with downtown neighborhood leaders and the city regarding residents’ complaints about the size of new buses SCAD deployed in early January. Smaller, 20-person student-shuffling buses that are about 25 feet long will be used on the college’s green and red routes, which go through squares in the Historic District, said SCAD spokeswoman Ally Hughes. In January, downtown residents and some city officials became concerned about the size of several large buses leased by SCAD, as well as the noise produced by the vehicles.