Devices and early warning methods used to reduce hits on low-clearance structures

Tennessee has one location on SR-27 that goes under I-24 in Marion County, better known as the Jasper/South Pittsburg Exit, with a low-tech warning system for overheight trucks. In advance of the bridge is an overhead sign with chimes hanging down from the sign. The message on the sign is “TRUCKS THAT HIT THIS WILL HIT BRIDGE” (black letters on yellow background). The chimes hang down to the height equal to the bridge clearance. If a tall truck hits the chimes, the noise is supposed to warn the truck driver that the vehicle will not clear the bridge. A picture of the device can be viewed on the web site below.