Dixon v. District of Columbia, 666 F.3d 1337

Dixon and Phung were arrested for speeding over 30 mph the by District MPD in 2008 and 2009, respectively.
They sued on behalf of others subjected to arrest and criminal penalties for the same conduct, alleging Fifth Amendment equal protection violations stemming from disparate penalties versus ATE civil fines.
ATE detects speeding via fixed-location cameras or mobile units, issuing civil fines to vehicle owners without criminal arrest.
MPD officers arrest speeding motorists, potentially leading to criminal penalties; the District argues this mixed enforcement serves deterrence and safety goals.
The district court dismissed the complaint under Rule 12(b)(6); the court acknowledged due-process-based equal protection but found no rational basis flaw in the policy.
The Court of Appeals affirms on the grounds that the policy is rational under rational-basis review because it advances deterrence and efficient enforcement.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether the District's disparate penalties violate equal protection.	Dixon argues motorists similarly situated are punished differently.	District contends rational-basis justification for varied enforcement.	No; rational-basis review sustains the classification.

Romer v. Evans, 517 U.S. 620 (U.S. 1996) (highly deferential rational-basis review applicable to non-suspect classifications)
FCC v. Beach Communications, Inc., 508 U.S. 307 (U.S. 1993) (equal protection not a vehicle for judging wisdom of policy; any conceivable rational basis suffices)
Hedgepeth v. Washington Metro. Area Transit Auth., 386 F.3d 1148 (D.C. Cir. 2004) (no fundamental right to movement when probable cause exists)
Virginia v. Moore, 128 S. Ct. 1598 (U.S. 2008) (probable cause supports warrantless arrests for observed crimes)
Atherton v. D.C. Office of the Mayor, 567 F.3d 672 (D.C. Cir. 2009) (de novo review of Rule 12(b)(6) dismissal; plausibility standard)