GIS Layer for Sidewalk Widths

We need created a GIS layer using ArcGIS, QGIS or similar of the average sidewalk width for sidewalk network in a city. Sidewalk widths are measured using satellite imagery from a source such as Google or Bing. Widths are measured at 3 locations for a given segment, at the beginning, middle and end. We will provide a target layer indicating the location of sidewalks where widths need to measured. Deliverable is the the sidewalk layer with the sidewalk widths measurements appended to the attributes.