The Sioux Empire Gay and Lesbian Coalition of Sioux City, S.D. filed suit in federal court Monday, after the South Dakota Department of Transportation rejected the group’s request for an Adopt-a-Highway sign. The coalition had filed a request to participate in the state’s highway clean-up program, which included an official roadside sign advertising the sponsoring group or individual. The Department of Transportation rejected the coalition’s request, citing it as an “advocacy group” ineligible for an official marker. The coalition has filed a federal lawsuit alleging denial of equal protection under the law and violation of free speech rights. Hundreds of community and civic groups in South Dakota currently participate in the program and received free advertising for their highway cleanup efforts. Participating groups include the College Republicans, Animal Rights Advocates of South Dakota, and Yankton County Democrats.