Colorado has safest drivers; DC's most likely to crash -report AUSTIN, Texas (Reuters) - The best drivers in the United States live in northern Colorado, while motorists on the crowded roadways of Washington, D.C., are twice as likely to crash as the national average, according to Allstate America's Best Drivers Report released this week. Drivers in the nation's capital get involved in crashes once every 4.8 years on average, compared with a national average of once per decade. The most dangerous cities to drive in after Washington are Baltimore; Providence; Hialeah, Florida and Glendale, California. New York drivers have crashes on average once every 7.3 years, while those in Chicago and Houston crash once every 8 years. By way of comparison, the average driver in Fort Collins, Colorado, crashes every 13.9 years. The next-safest cities were Boise, Idaho; Sioux Falls, South Dakota; Brownsville, Texas and Madison, Wisconsin. The report, released Tuesday, surveyed Allstate insurance claims over 2011 and 2012 in 200 of the United States' largest cities to determine how often drivers there have crashes. The company uses the two-year time frame in each annual report to mitigate any spikes in the numbers due to weather events or similar unusual influences on the statistics. Allstate drivers make up about 10 percent of all insured motorists nationwide, the report said. The report draws distinctions between driving in big cities, where traffic, emergencies, public transportation and simply getting lost pose more dangers, and small-town driving, where high speed limits, fewer crosswalks and large vehicles are among the most common threats. Indeed, almost all of the 20 cities with the safest drivers have less than half a million residents, the largest of them Tucson, Arizona, with 524,000 residents and crashes happening to drivers about once every 11.4 years - similar to Lincoln, Nebraska, which is about half the size. Larger or more crowded cities landed on the bottom of the list. The 20 least safe cities for drivers include Los Angeles, Philadelphia, San Francisco, Newark and Miami. Reporting by Karen Brooks; Editing by Scott Malone and Phil Berlowitz