Senior citizens who want a 50 percent toll discount on four area bridges now must provide the Delaware River Port Authority with copies of their driver's license and vehicle registration each year.The DRPA, which operates the Ben Franklin, Walt Whitman, Betsy Ross, and Commodore Barry bridges, has begun to send notices to the roughly 50,000 people who currently receive the lower rate, notifying them of the new rule. Some are not happy about the change. "When I first joined up, I didn't even have to have a license," said Harold Fisher, 73, of Pennsauken, who said he travels to Philadelphia daily. "You could have your grandson drive you across the bridge. It was for the benefit of the senior citizen. ...