A--braking system
B--breakdowns C--brick
road
D--bridge E--bridge
management system
F--broken stone surface G--bus management information system
H--bus network I--bus- kilometer
J--bypass road K--cable car, cableway
L--centre line lane M--changing lane
N--climbing lane O--connecting road
P--control station Q--counter flow
R--cross road S--direct bus
T--divided road 爬坡车道 ( ) 桥梁管理系统