What is the correct way to find the width of the street?

The credit requirements do not seem to be consistent in defining the street width. First they require a minimum building-height-to-street width ratio of 1:3, "measured to the centerline of the street." A bullet point directly underneath this statement says that "street width is measured facade to facade." Should I measure from the facade of the project building to the facade of the building across the street? Or, should I measure from the facade of the project building to the centerline of the street, and do I multiply this number by 2? If anyone can shed some light on this confusing issue I would greatly appreciate it. Thanks!