Overtime cracks may form in the asphalt surface allowing water to enter and deteriorate the sub-grade and eventually the surface.  This usually results in alligatoring and potholes.  A hot pour D.O.T. approved cracker filler can be applied into the cracks to protect the lot from further damage.  Crack filling is recommended for all cracks ¼ inch or wider.  The lot can then be seal-coated to obtain a uniform appearance.