(a) Unless there is a special danger that requires a lower speed to comply with § 21-801 of this subtitle, the limits specified in this section or otherwise established under this subtitle are maximum lawful speeds. A person may not drive a vehicle on a highway at a speed that exceeds these limits.

(b) Except as otherwise provided in this section, the maximum speed limits are:

(1) 15 miles per hour in alleys in Baltimore County;

(2) 30 miles per hour on:

(i) All highways in a business district; and

(ii) Undivided highways in a residential district;

(3) 35 miles per hour on divided highways in a residential district;

(4) 50 miles per hour on undivided highways in other locations; and

(5) 55 miles per hour on divided highways in other locations.

(c) Except as provided in subsection (e) of this section, a posted maximum speed limit lawfully in effect on December 31, 1974, is a maximum lawful speed even if it differs from a limit specified in subsection (b) of this section.

(d) Except as provided in subsection (e) of this section, a maximum speed limit specified in subsection (b) of this section or in effect under subsection (c) of this section may be altered as provided in this subtitle.

(e) (1) Notwithstanding any other provision of this subtitle, a maximum speed limit of more than 55 miles per hour may not be established or continued on any highway in this State that is not an interstate highway or an expressway.

(2) Subject to the provisions of paragraph (1) of this subsection, a maximum speed limit of more than 70 miles per hour may not be established on any highway in the State.

(f) (1) Unless otherwise posted on a public road in a residential subdivision, in residential subdivisions in St. Mary’s County, a posted speed limit on a main access road applies to all public roads in the residential subdivision, even if the posted speed limit on the main access road is less than 30 miles per hour.

(2) The provisions of paragraph (1) of this subsection do not apply when a through road traverses a residential subdivision. The maximum speed limit applicable to the subdivision shall be posted on each road exiting off the through road and into the subdivision, along with the posting on the main access road.

(3) A maximum speed limit established under this subsection in a residential subdivision shall be based on the subdivision’s road design, motor vehicle traffic, and pedestrian safety.