Anyone who lives or works close to I-70 understands the amount of noise highway traffic can generate. With added lanes and increases in future traffic, many have questioned the need for sound walls along the interstate.

Each of the seven Improve I-70 study teams completed a sound analysis of the I-70 corridor to determine today’s noise levels and estimate how noise might change by the year 2030 due to I-70 widening. The analysis identified general areas where sound walls might be needed in the future. Each team’s findings and recommendations are included in official environmental documents, which are available by clicking on Local Focus.

The Improve I-70 Studies did not determine exactly where sound walls could be or what they might look like. Final decisions on the location and appearance of sound walls would be made through a public involvement process that happens during the design phase, which is currently unfunded.

During the design phase, MoDOT would use policies approved by the Federal Highway Administration to guide decisions about where to place sound walls. In general, the following criteria must be met before a sound wall can be constructed:

• Hourly noise levels must exceed 66 dBA Leq (dBA Leq is an accepted measurement unit for highway noise)
• The sound wall must provide noise reduction of at least five dBA for those homes closest to the highway
• The sound wall must provide decreased noise for more than one home
• The sound wall cannot be taller than 18 feet
• The sound wall must not interfere with normal access to the property
•   The sound wall must not pose a traffic safety hazard
•   The sound wall must not exceed a cost of $30,000 per benefited property
•   The majority of the benefited residents must agree that a sound wall is desired

Much more information about sound walls is available on MoDOT’s Web site at www.modot.org.