Centennial leads the list of safest cities in Colorado for the fifth year in a row.And according to CQ Press, Centennial rates as the 15th safest city in the United States.Were extraordinarily proud of that recognition, said Arapahoe County Sheriff Grayson Robinson, whose office provides safety services for the south metro suburb.Robinson attributes the high ranking to community policing and effective problem solving.We strive to identify challenges and solve them before they become a problem, the sheriff said.When asked for an example, Robinson cited an increase in residential burglaries three years ago.We later found that many were the result of people leaving their garage doors open, so we implemented an initiative called drop it, stop it and lock it, Robinson said.The initiative, which encouraged homeowners to close their garage doors, helped reduce burglaries 20 percent.Centennial resident Amy Plank told 7NEWS that the ranking is about right.Plank said that Centennial is safe because people watch out for each other and dont hesitate to get involved.Its like a small town in a way, she said. You see the same people in the grocery store and at the doctors office and you feel comfortable.Tanya Schaffer has lived in Centennial for two and a half years.She too said the ranking was justified.I know in my neighborhood we really look out for each other, Schaffer said.The mother of three said she brings her 11-year-old daughter with her to work in the morning and then allows the girl to walk to the bus stop on her own to get to school.I like being able to do that, she said. In Denver, I dont feel I would let her do that.Still there is crime in Centennial.On Monday night, 200 people attended a community meeting to learn about the unsolved murder of Andrew Graham, a CU grad who was shot in the back and found dead in the front yard of a home in the Willow Creek subdivision, Nov. 6.Robinson said it will take help from the community to solve the crime.Even taking into consideration Andrews death, this is still a very safe community, Robinson said. That said, we still ask our citizens to take appropriate safety measures.Centennial Mayor Randy Pye said citizen involvement plays a key role in the rankings.He said it goes back to when Centennial was formed in 2001.The citizens really believe they own the city of Centennial, which they do, Pye said. They have ownership in it and so they take ownership of how safe it will be as well.The 2009 rankings are based on reported murder, rape, robbery, aggravated assault, burglary and motor vehicle theft cases per 100,000 people.Law enforcement agencies, including the FBI, say there are many factors that play a role in crime rates, among them, population density, composition (particularly youth), climate, economic conditions, citizen attitude, cultural factors, education levels and crime reporting practices.Arvada ranks 58th on the Safest Cities list. Boulder is 64th. Denver is 227th.The cities with the worst crime rates are Camden New Jersey and St. Louis Missouri.Only cities with populations above 75,000 are included in the study.