(a) The Chief of Police shall have authority to declare any street or part thereof a play street and to place appropriate signs or devices in the roadway indicating and helping to protect the same.
(b) Whenever authorized signs are erected designating any street or part thereof as a play street, no person shall drive a vehicle upon any such street or portion thereof except drivers having business or residing within such closed area, and then any such driver shall exercise the greatest care in driving upon any such street or portion thereof.