(a) If streets are to be constructed out of “full-depth” asphalt, an asphalt pavement in which asphalt-aggregate mixtures are used for all courses above the subgrade may be necessary. The City Engineer will determine pavement thicknesses. For local streets pavements may vary from four (4) to seven (7) inches depending upon subgrade conditions. For collector streets, pavements may vary from five (5) to nine (9) inches, and for arterial and industrial streets from six (6) to eleven (11) inches, depending upon the Engineer's recommendation.