How is the system being upgraded and expanded?

Currently,there are 73 sirens dispersed throughout Davidson County. They are primarily located at public schools, parks and major intersections. The 2013 upgrade and expansion of the system includes adding 20 new sirens to cover additional areas of the county and replacing the current sirens with new equipment. The original siren locations were selected based on the 2000 census data and outdoor population expectations. The location selection for the additional sirens was based on the same methodology, using the latest 2010 Census data.Once the upgrades are complete, all of the tornado sirens in Davidson County will have a new sound resembling an old-fashioned air-raid warning, which has a lower frequency and greater sound reach than the high-pitched electronic tone currently used.