Lucky for River Downs, it doesn't race live at night.Cincinnati, Ohio, Mayor Charlie Luken has issued a citywide curfew for all citizens from 8 p.m. to 6 a.m. each day while the city copes with unrest brought about by the shooting of a black man by a white police officer. Cincinnati has been plagued by looting and violence since the incident April 7. The National Guard has been called in.River Downs, which opens for its live meet Friday, is located a stone's throw from the Cincinnati corporate limit in Anderson Township. Though the track races in the afternoon, it's open until about midnight for simulcasting. Patrons from Cincinnati won't be able to hang around for the nighttime action while the curfew is in effect, said John Engelhardt, the track's publicity director.It will be business as usual during the afternoon and early evening."Some of our patrons may have to leave early," Engelhardt said. "They have to be in their homes by 8 o'clock." Track employees and others who work at night will be permitted to travel from work to their homes.The Cincinnati Enquirer reported that Luken asked for help from Ohio Gov. Bob Taft, who was to send 75 members of the Ohio State Highway Patrol to Cincinnati Thursday to assist in the effort. Streets must cleared by 8 p.m. each day during the state of emergency.