Quiet Pavement The Decibel Scale Increasing the decibel level by 10 doubles the noise intensity! Conversation Train Chain Saw
Quiet Pavement The Decibel Scale A reduction of 3 dB(A) is like doubling the distance from the noise. 67 dB(A) 50 ft
Quiet Pavement The Decibel Scale A reduction of 3 dB(A) is like doubling the distance from the noise. 67 dB(A) 100 ft - 3 dB(A) = 64 dB(A)
Quiet Pavement Noise Makes News! Road Surface Material Can Reduce Noise –“Bituminous surfaces generally produce less noise than do concrete surfaces...” Star-Tribune, Minneapolis, MN, March 21, 1999, pg. 6E. Drivers on Exeter, U.K.’s A30 Complain About Noise from Concrete Surface, Joining Residents for Asphalt Resurfacing –Western Morning News, Exeter, U.K., December 4, 1999
Quiet Pavement Noise Makes News! Residents Living Near New York City’s Long Island Expressway are Upset at Noise from New Concrete Roadbed –Daily News, Donald Bertrand, New York City, Sept. 20, 1999, Suburban, pg. 1 Livonia Residents Complain of Freeway Noise –“Hundreds of people who live along I-275... have complained about increased noise... since the state re-paved the road with concrete.” The Detroit News, Sheri Hall, Livonia, MI, November 3, 2000, http://detnews.com/wayne/0011/03/
Quiet Pavement Noise Makes News! What can be done? –Erect Noise Walls –Plant Trees/Shrubs –Surface Pavement with Hot Mix Asphalt Open-Graded Friction Course Stone Matrix Asphalt Dense-Graded HMA
Quiet Pavement Noise Walls Effective only for those not in line-of-sight. Do not reduce noise at source.
Quiet Pavement Effectiveness must justify expense. Cases: –I-40, Knoxville: >$25,000/home –I-285, Atlanta: Requirements of > 69 dB(A) and < $50,000/home –U.S. 441, West Boca, FL: > 67dB(A), 5dB(A) Noise Walls
Quiet Pavement Noise factors including vehicle type, speed, and tire tread are beyond control of agency. A recent survey shows (NCHRP Synthesis 286) pavement texture is most important factor in highway noise. Pavement texture can be controlled. What Can Be Done?
Quiet Pavement DOTs indicate a strong need for pavement noise control strategies. Proper selection of pavement surface is the best method to reduce noise from pavement/tire interactions. What Can Be Done?
Quiet Pavement Noise Generators Major noise generators of vehicles are: –engine, –exhaust system, –aerodynamic noise, and –tire noise. (Herman, TRR 1626; McNerney, et al., TRR 1626) For > 50 mph, pavement/tire noise dominates. (Billera, et al., TRR 1601)
Quiet Pavement Effect of Pavement Surface Swedish study - pavement surface can cause a change of up to 15 dB(A). (Sandberg, Inter-Noise 79, 1979) Noise studies in U.S. and Europe show asphalt surfaces quieter than PCC. (Wayson, NCHRP Synthesis 268)
Quiet Pavement Open-graded asphalt surfaces are up to 10 dB(A) quieter than transversely tined PCC pavements. (Hibbs and Larson, FHWA- SA-96-068, 1996; Jofre, et al., 7th Int’l Symposium on Conc. Roads, 1994; Younger, et al., FHWA-OR-RD- 95-13B, 1994) A decrease of 3 dB(A) is significant. Has the same effect as doubling distance. Effect of Pavement Surface
Quiet Pavement OGFC is the quietest surface type. (Wayson, NCHRP Synthesis 268) SMA has also proven to be a quiet surface. (Wisconsin DOT, 1993) Dense graded HMA surfaces are quieter than PCC pavements. (Hibbs and Larson, Report FHWA-SA-96-068, May 1996) Effect of Pavement Surface
Quiet Pavement Summary Highway noise is important to the public. Small changes in dB level are noticeable. –Increase of 10 dB(A) doubles noise –Decrease of 3 dB(A) is like doubling distance
Quiet Pavement Summary Noise walls can work, but: –They are expensive. –They don’t work in all types of terrain. –Source of noise is still there. Asphalt pavements can reduce noise up to 10 dB(A).
Quiet Pavement Hot Mix Asphalt Summary Asphalt pavements for noise reduction in order of effectiveness: –OGFC –SMA –Dense-Graded HMA (NCHRP Synthesis 268) PCC