Columbia subject headings:
Buses--Barrier-free design--United States.
Buses--United States--Safety measures.
People with disabilities--Transportation--United States.
Transportation and state--United States.
Harvard subject headings:
Buses--Barrier-free design--United States
Buses--United States--Safety measures.
People with disabilities--Transportation--United States
Transportation and state--United States.
Princeton subject headings:
Buses--Barrier-free design--United States.
Buses--United States--Safety measures.
People with disabilities--Transportation--United States.
Transportation and state--United States.