The federal government has denied Concord's request to use a modified wheelchair icon intended to empower and welcome people with disabilities.The Accessible Icon Project began in 2010 in Cambridge, Massachusetts, as a guerrilla art campaign. The wheelchair user depicted in the icon leans forward instead of straight up.Concord sent a letter to the Federal Highway Administration in August asking for permission to use the symbol on Main Street. The city received a $4.71 million grant for a Main Street project from the federal agency and needed their approval.The Concord Monitor reports officials denied the request on Monday, saying they support its principle and objective, but that the symbol is not authorized for use. It also has not been adopted or endorsed by the U.S. Access Board.