A bicylist sporting dreadlocks has a virtual police escort while riding with a group called Critical Mass that make a monthly bike tour. There have been arrests involving group members on past rides. The estimated 500 riders, however, were accompanied by dozens of police officers - both on bikes and in squads and unmarked vehiles - and there were no major incidents along the route that meandered around downtown Minneapolis from Loring Park toward St. Paul and back to Minneapolis.