roadtype 0
4 bits for type
5 owner bits   (m1 4-0)
4 road bits    (m5 3-0)

roadtype 1
4 bits for type
5 owner bits   (only 4 allocated currently as towns don't build trams, m3 7-4, one more needed)
4 road bits    (m3 0-3)

Total bits needed 18
Already provided  13
Need to allocate   8