Residents of Cedar Rapids, Iowa, rank as the safest drivers in the U.S. according to the Allstate Insurance Company's inaugural "America's Best Drivers Report." The ranking of U.S. cities revealed that the average driver in the central Iowa city will experience an auto collision every 15 years, compared to the national likelihood of a crash every 10 years - making them 33.28 percent less likely to have an accident than the national average. Allstate researchers analyzed internal data to determine the likelihood drivers in America's largest 196 cities (with populations over 100,000) would experience an auto collision compared to the national average. Drivers in U.S. cities with populations of one million-plus are more likely than the national average to experience a collision. Phoenix, the top-ranked city in this category, mirrors the national collision average of one accident every 10 years. According to the report, Milwaukee drivers will experience a collision approximately every 11.5 years and rank as the safest of the metros with populations between 500,000 and one million residents. "Many factors contribute to how cities rank in the report," said Allan Williams, the recently retired chief scientist and researcher at the Insurance Institute for Highway Safety. "Some factors - demographic makeup, commuting patterns and city design - cannot be changed; others, like smart traffic engineering and strong law enforcement initiatives, can help to prevent crashes in metropolitan areas." According to insurance.com, more crashes occur on Saturdays than any other day of the week. Friday ranked second and Thursday came in third. Collisions are least likely to occur on Sundays. Collisions are most likely to happen between 3 and 6 p.m. From 6 and 9 p.m. ranked second and 9 p.m. - midnight finished third. The fewest crashes occur between midnight and 3 a.m.