Noise barriers are solid obstructions built between the highway and businesses or residences along a highway. Effective noise barriers typically reduce noise levels by 5 to 10 dB(A), which reduces the loudness of traffic noise by as much as one-half.

Noise barriers typically consist of concrete/wood composite panels placed between steel supports. The height and location of a barrier is determined by the TNM analysis. The color and texture can vary, and INDOT seeks the input of adjacent property owners.

Noise barriers reduce the sound from a highway by absorbing the sound, reflecting it back across the highway or forcing it to take a longer path to receivers. A noise barrier must be tall enough and long enough to block traffic noise from the area that is to be protected.

INDOT considers noise abatement when a noise impact occurs and a barrier is considered to be feasible and reasonable.


  • Acoustic Feasibility – Achieves at least a 5 dB(A) reduction in traffic noise for a majority (>50%) impacted properties
  • Engineering Feasibility – Considers environmental, drainage, safety, existing bridges, and other issues to identify best location for a barrier


  • Noise Reduction Goal – 7 dB(A) reduction for impacted first-row properties
  • Cost-effectiveness
    • INDOT uses $30/sq. ft. to estimate barrier cost
    • Cost per benefited receptor of $25,000 or less is considered cost-effective. Cost per benefited receptor goes up to $30,000 if the majority (>50%) of the homes were built prior to initial construction of the roadway
  • Views of Residents and Property Owners
    • INDOT considers the views of all benefited residents and property owners to determine whether a barrier is appropriate for a given location

See before and after renderings of the proposed North Split noise barriers
See the noise abatement FAQs
NEW! See the supplemental noise abatement FAQs
Return to the noise abatement page