Wheelchair fatality in Knoxville

The Knoxville News Sentinel is reporting on a fatality of a motorized wheelchair user who was struck by a right-turning vehicle. The vehicle was turning right onto Kingston Pike from the western end of Forest Glen Drive around 1:30 PM, on September 28, and apparently struck the wheelchair when the wheelchair entered the intersection from the sidewalk. Forest Glen Drive has a stop sign for the car. The crash is still under investigation. Details are sketchy. What are some safety tips for wheelchairs out in traffic, and what can people do to make tragedies like this one less likely to occur in the future? Are wheelchairs more like pedestrians, or more like slow vehicles in their handling characteristics?