Bridge plates are used on some low-floor light rail vehicles to provide for wheelchair

access. The bridge plate extends from the vehicle to the platform, which must be

raised to close to the level of the floor of the vehicle so that the wheelchair need not

travel over an excessively steep ramp (in the United States, the Americans with

Disabilities Act specifies that the slope must be no more than 1 inch of rise for every

12 inches of length). Some low-floor buses also use bridge plates (in this case,

extending to the curb) to provide for wheelchair access, but many low-floor buses

instead use a ramp that normally serves as part of the floor but can be flipped out

through the door (using a hinge at the door) onto the curb or street; in this case the

ramp is long enough that it can serve as a true wheelchair ramp rather than a bridge

without being excessively steep.