An accident Thursday morning on Highway 6 and 50 near the Mesa Mall is the latest in a string of deadly crashes this week in Grand Junction. Two of them involved motorcycles. Law enforcement agencies are concerned that with the influx of motorists to the Grand Valley for the Memorial Day weekend and the Junior College World Series, the death toll could rise. Grand Junction police and Colorado State Patrol troopers will be out in full force this holiday weekend participating in the Click It Or Ticket campaign, but also hoping to remind drivers to slow down and obey the rules of the road. On Monday a Palisade man was killed when his motorcycle collided with a truck at the intersection of 12th Street and Patterson Road. Neither motorcyclists in either crash this week was wearing a helmet. While Colorado is one of only three states in the U.S. that does not have a law requiring motorcycle riders to wear helmets, law enforcement does encourage the use of protective gear. According to the National Highway Transportation Safety Administration helmets are 37 percent effective in preventing fatal injuries.