Except as provided in § 4–409 of this subtitle, this subtitle does not apply to any public improvement made by: the Department of Transportation or a unit in that Department; any housing authority created under Division II of the Housing and Community Development Article; the Maryland–National Capital Park and Planning Commission; the Washington Suburban Sanitary Commission; the Baltimore County Metropolitan District; a county, municipal corporation, or unit of a county or municipal corporation; the University System of Maryland; Morgan State University; St. Mary’s College of Maryland; or Baltimore City Community College, if the value of the contract for the public improvement is $500,000 or less. The Board of Public Works may exempt specific projects of a unit of the State government from the provisions of this subtitle. The Board of Public Works shall adopt regulations in accordance with Title 10, Subtitle 1 of the State Government Article establishing procedures for the exemption of specific projects of units of State government under subsection (b) of this section.