"She looked a little puzzled," was how newsroom colleague Catherine Preus described the driver she encountered Thursday morning on her bike commute to work. "Like, 'why is this so narrow?'" No wonder. Preus was just coming off the east end of the Martin Olav Sabo bike-ped bridge over Hiawatha Avenue on the Midtown Greenway. The lady heading past her in the tan mid-sized sedan was heading westbound across the bridge. An astonished Preus watched as the woman slowly drove across the greenway bridge and down the western approach. "No way!" reacted Shaun Murphy, a city bike planner. Actually the bridge is built strongly enough to handle maintenance vehicles, he said, but neither Murphy nor the staff at the Midtown Greenway Coalition had heard of a regular motorist straying over the bridge before. Preus said she got a good look at the lady because she was driving slowly. She described her as appearing to be in her 60s, with short dark hair with a red tint, bright old-lady lipstick and generous wrinkles. Preus and other bikers, who tried to wave the lady over, had to move to the side to let her past. Preus notified an incredulous Metro Transit officer at a nearby Hiawatha line station. It's possible for a straying motorist to access the bridge from several places where bike trails cross nearby arterials, but there are sharp turns on the trails leading up to the bridge. The bridge opened in 2007 and is named after the former congressman who advocated for federal aid for the span. A 2010 count estimated that it carries more than 2,200 riders on a typical weekday.