Noise barriers are solid obstructions built between the highway and the homes along a highway. They do not completely block all noise they only reduce overall noise levels. Effective noise barriers typically reduce noise levels by 5 to 10 decibels (dB), cutting the loudness of traffic noise by as much as one half.

A highway sound barrier is a wall that is constructed between the noise source (highway traffic) and the areas that require noise insulation (neighborhoods and public spaces). Although they do not completely eliminate noise, they can significantly reduce its impact by deflecting, absorbing, or transmitting sound waves.

A highway sound barrier is an exterior wall built alongside a roadway or highway that interrupts the flow of sound waves from one area to another. Two types of highway sound barriers are used: A reflective wall, which is solid, will break up sound waves and reflect the noise back to the source location.