CTC: Information

Bringing down the noise: Noise reduction technologies and strategies

1. Quiet pavement

TxDOT should overlay the freeway surface to directly reduce the noise produced by vehicles. "Rubberizing" highway surfaces by including recycled tire materials in the road surface mix is now a proven technology. Studies suggest his technique reduces vehicle noise caused by tires on the road surface by 4-8 decibels. Quiet pavement is being used effectively in Arizona and also in many European nations such as The Netherlands. Based on the Arizona experience, long-term maintenance is not adversely affected. The technique is cost-effective: Arizona spent less than $300,000 per mile. TxDOT has already conducted one quiet pavement pilot project in San Antonio.

For more information, visit:

Arizona DOT's Quiet Roads pilot project website
QuietPavement.com presented by the Asphalt Pavement Alliance
AsphaltRubber.org Highway traffic noise comparison (mpg movie)

2. On-structure, high-tech barriers

Effective sound barriers can cut noise levels by 10-15 decibels, or in half. Basic sound barriers are widely used by TxDOT as a noise reduction strategy, and should be added to key locations. New, modern designs could prove especially useful. Further, on-structure barriers (rather than at the edge of the highway property) should be pursued. These can be concrete, brick or glass fiber- reinforced concrete (usually called GRC) or proprietary acoustic panels. Engineering will need to address wind torque issues and aesthetics. On-structure barriers are pictured in TxDOT's older noise mitigation brochures and are used in many states. In the Houston district, you can see 6' on-structure walls along I-610 where it runs through the City of Bellaire.

3. Noise absorptive walls

Rather than simply reflect noise, walls and other highway structures can be designed to absorb sound. Also, the surfaces can be designed to encourage vegetation and vines (see US-59 at Shepherd Drive for an example). Aesthetics should be considered. Along many highways, such as the George Washington and Baltimore Parkways, concrete molds and stains are used to mimic native stones. Many cities such as Phoenix, AZ, Sacramento, CA, and Bellevue, WA have innovative, inexpensive designs for noise walls.

For more information, visit:

BetterRoads.com Overview of sound wall offerings from many vendors

4. Noise insulation

Nearby buildings impacted by noise and vibration could be protected using standard sound insulation technology. This would include installing double- or triple-paned windows, and insulating roofs and walls. These techniques are already used near some railroads and airports in Houston. Such techniques would also benefit public buildings facilities inside the parks.

5. Non-noise-reducing aesthetic and habitat parkland mitigation

TxDOT could offset impacts to wildlife habitat in Memorial Park and the Houston Arboretum by acquiring additional land for habitat and improving habitat in other areas of the parks. TxDOT could offset impacts to the recreational uses of Memorial Park by funding new park amenities such as fountains, landscaping, and access features. These would essentially serve as compensation in lieu of effective noise mitigation.

6. Cash payments for inverse condemnation

TxDOT can provide affected property owners with cash compensation for reduced property values. This remedy may be particularly suitable for office buildings, other private commercial structures, and schools.

7. Structural realignment

Lowering freeway structures or even depressing them below grade keeps traffic noise from traveling as far. Federal regulations expressly provide for structural realignment as an appropriate remedy for highway noise. TxDOT can lower elevated anti-weaving ramps to both reduce noise and improve aesthetics.

For more information, visit:

Federal Highway Administration Highway traffic noise regulations and guidance
Texas DOT's Environmental resources for transportation professionals
Texas DOT's Guidelinesfor analysis and abatement of highway traffic noise (447kb PDF)

Citizens' Transportation Coalition: advocacy information organization forums
Citizens' Transportation Coalition, Inc. Copyright© 2004-2007. All rights reserved.
address: PO Box 66532 Houston TX 77266-6532 phone: 713-301-5716 email: chair@ctchouston.org



Bringing down the noise: Noise reduction technologies and strategies 1. Quiet pavement TxDOT should overlay the freeway surface to directly reduce the noise produced by vehicles. "Rubberizing" highway surfaces by including recycled tire materials in the road surface mix is now a proven technology. Studies suggest his technique reduces vehicle noise caused by tires on the road surface by 4-8 decibels. Quiet pavement is being used effectively in Arizona and also in many European nations such as The Netherlands. Based on the Arizona experience, long-term maintenance is not adversely affected. The technique is cost-effective: Arizona spent less than $300,000 per mile. TxDOT has already conducted one quiet pavement pilot project in San Antonio. For more information, visit: Arizona DOT's Quiet Roads pilot project website QuietPavement.com presented by the Asphalt Pavement Alliance AsphaltRubber.org Highway traffic noise comparison (mpg movie) 2. On-structure, high-tech barriers Effective sound barriers can cut noise levels by 10-15 decibels, or in half. Basic sound barriers are widely used by TxDOT as a noise reduction strategy, and should be added to key locations. New, modern designs could prove especially useful. Further, on-structure barriers (rather than at the edge of the highway property) should be pursued. These can be concrete, brick or glass fiber- reinforced concrete (usually called GRC) or proprietary acoustic panels. Engineering will need to address wind torque issues and aesthetics. On-structure barriers are pictured in TxDOT's older noise mitigation brochures and are used in many states. In the Houston district, you can see 6' on-structure walls along I-610 where it runs through the City of Bellaire. 3. Noise absorptive walls Rather than simply reflect noise, walls and other highway structures can be designed to absorb sound. Also, the surfaces can be designed to encourage vegetation and vines (see US-59 at Shepherd Drive for an example). Aesthetics should be considered. Along many highways, such as the George Washington and Baltimore Parkways, concrete molds and stains are used to mimic native stones. Many cities such as Phoenix, AZ, Sacramento, CA, and Bellevue, WA have innovative, inexpensive designs for noise walls. For more information, visit: BetterRoads.com Overview of sound wall offerings from many vendors 4. Noise insulation Nearby buildings impacted by noise and vibration could be protected using standard sound insulation technology. This would include installing double- or triple-paned windows, and insulating roofs and walls. These techniques are already used near some railroads and airports in Houston. Such techniques would also benefit public buildings facilities inside the parks. 5. Non-noise-reducing aesthetic and habitat parkland mitigation TxDOT could offset impacts to wildlife habitat in Memorial Park and the Houston Arboretum by acquiring additional land for habitat and improving habitat in other areas of the parks. TxDOT could offset impacts to the recreational uses of Memorial Park by funding new park amenities such as fountains, landscaping, and access features. These would essentially serve as compensation in lieu of effective noise mitigation. 6. Cash payments for inverse condemnation TxDOT can provide affected property owners with cash compensation for reduced property values. This remedy may be particularly suitable for office buildings, other private commercial structures, and schools. 7. Structural realignment Lowering freeway structures or even depressing them below grade keeps traffic noise from traveling as far. Federal regulations expressly provide for structural realignment as an appropriate remedy for highway noise. TxDOT can lower elevated anti-weaving ramps to both reduce noise and improve aesthetics. For more information, visit: Federal Highway Administration Highway traffic noise regulations and guidance Texas DOT's Environmental resources for transportation professionals Texas DOT's Guidelinesfor analysis and abatement of highway traffic noise (447kb PDF)
Citizens' Transportation Coalition: advocacy information organization forums Citizens' Transportation Coalition, Inc. Copyright© 2004-2007. All rights reserved. address: PO Box 66532 Houston TX 77266-6532 phone: 713-301-5716 email: chair@ctchouston.org