Prediction of noise reduction through vehicle path rerouting

Area of Science:

• Acoustics
• Environmental Engineering
• Urban Planning

Background:

• Traffic noise is a significant environmental concern, quantified by metrics like day-night average sound level (L(dn)) and day-evening-night level (L(den)).
• Current noise assessment typically assumes rectilinear paths for noise sources, such as road vehicles.
• Noise barriers are a common but often costly solution for mitigating traffic noise.

Purpose of the Study:

• To investigate the potential for noise reduction by modifying the geometry of noise source paths from straight to curved.
• To derive a quantitative relationship between road curvature and traffic noise reduction.
• To evaluate the feasibility of curved road designs as an alternative to noise barriers.

Main Methods:

• Modeling traffic noise propagation considering geometrical spreading, air absorption, and ground effect.
• Substituting a circular arc path of radius R for a rectilinear path segment.
• Deriving the noise reduction (DeltaL) as a function of the radius (R) and the angle (Phi) of the arc.

Main Results:

• A formula was derived to calculate noise reduction (DeltaL) based on road curvature parameters.
• A specific example demonstrated that replacing a 100m straight road segment with a 270m radius arc (68 degrees) can yield a 4 dB noise reduction.
• The calculated noise reduction is applicable to both L(dn) and L(den) metrics.

Conclusions:

• Modifying road geometry to include curves offers a quantifiable method for traffic noise reduction.
• Curved road designs present a promising, potentially more cost-effective alternative to traditional noise barriers for road traffic.
• Further research could explore optimal curvature parameters for maximum noise reduction in various urban settings.