NPD P1 Walkable Street requires at least 15% of existing and new street frontage within and bordering the project has a minimum "building-height-to-street-width ratio" of 1:3.

Can anybody explain the definition of street frontage? Can I understand that it is a building facade runs parallel to an street?

There is a community in my hand that most of its building facade are not designed alongside the street, how can I identify the eligible ratio then?