A class: Lines in this class are BG sections rated for speeds up to 160km/h
B class: This class allows speeds up to 130km/h
C class: This is not really a speed-rated class, but is the classification used for suburban sections of metropolitan areas.
D-special class: BG lines rated up to 100km/h, with high traffic density or high expected growth in traffic
D...
more... class: BG lines rated up to 100km/h.
E-special class: BG lines with sanctioned speeds below 100km/h, with high traffic density or high expected growth in traffic