Research Idea Details

Research Idea Scope

Develop improvements to the FHWA TNM and traffic noise-analysis techniques to address the following: 1) Effects of Irregular Terrain – Highway sites may include terrain with undulations of varying size, with slopes to and from the roadway to the receiver, or with sharp discontinuities (cut or elevated roadway). There is a need to validate existing traffic noise-analysis techniques to ensure that irregular terrain effects are accurately considered. 2) Vehicle Source Energy Distribution – In the FHWA TNM, the total sound energy emitted by a vehicle source is apportioned between two subsources before being propagated out to receptors. There is a need to determine if there is a significant dependence of subsource-height relationships on vehicle speed, pavement types,
graded versus level roadways, or interrupted-flow conditions. Improvements will allow for a more accurate and efficient analysis of noise impacts and development of more cost-effective noise mitigation.

TERI Administrator Note (June 2007): Research Underway
FHWA FY07 STEP Project: FHWA Traffic Noise Model/Pavement Validation Study

This research will begin by determining the validity of the FHWA TNM v2.5 in relation to varying the pavement type. The validity of introducing more advanced pavement affects into future versions of the FHWA TNM is also needed. This will be done by performing validation studies, which involve data collection, FHWA TNM modeling, and the comparison of measured and predicted data.

Urgency and Payoff

The FHWA TNM is a state-of-the-art prediction model that is used to address many analytic
complexities; for example, vehicle emissions, roadway geometry, and site characteristics.
Validation studies are necessary to ensure accurate analysis of these complexities.