LAYTON -- Noise levels on state roads will be a little lower in the future.
The Utah Department of Transportation recently revised its noise-abatement regulations, adding new projects that will require noise studies and increasing the minimum noise-reduction levels that must be met for proposed noise walls.
Noise studies will now be required for any projects that include an auxiliary lane or the relocation of an interchange ramp.
In the past, noise studies were not needed for those types of projects, said Brandon Weston, a UDOT project manager.
The new rule will likely affect several projects in the Top of Utah during 2012, as the state plans to add auxiliary lanes on Interstate 15 in Clearfield and Farr West and adjust an interchange on U.S. 89.
Also under the new rule, proposed noise walls will now have to create a minimum noise-level reduction of at least 8 decibels.
Weston said that, under the old policy, the noise-reduction level was only 5 decibels.
One caveat to the noise rule is that, if the measure of 8 decibels cannot be achieved by a sound wall or any other sound-mitigating procedure, the wall will not be built.
"If we can't reach that (decibel) level, we won't put a sound wall in," Weston said. "So if it can't achieve a certain level (of noise reduction), we won't spend the money for the wall."
Also, UDOT must now provide local governments with an estimate of future noise levels on undeveloped land near new road projects.
For UDOT to even consider noise walls, a road must be either an interstate or a limited-access highway and the cost of abatement must not exceed $30,000 per residence.
The expected impact of the road must also be 10 decibels more than the noise level before changes in the road configuration, or greater than 65 decibels.
Those affected by the road also have to be in favor of abatement.