Self-weathering poles and Lapp "Vee" type polymer insulators are taking over Middle Tennessee due to cost, reliability, and ease of installation, not to mention that they perform very well in pollution heavy areas. The line is ran at 161 Kv, double circuited... TVA owns this line along Interstate 440 west. It used to run on steel lattice towers, however 440 was expanded in the nineties and these were installed to replace the steel towers. This line construction is very common in Colorado and the western US, but rapidly spreading across the country for many many reasons.