LowEmissionAsphalt-136pg-WhitePaper-May2023

P a g e | 92 other “noise” coincident when testing using air quality monitors in small sample areas. Since CO 2 and NO 2 have near identical atomic mass, one can assume the CO 2 R 2 would be the same for NO 2 . 195 Table 11 – Relative Change in % Fuel Consumption by 1% Increase in Condition Variable 196 Rutting IRI Macrotexture car -0.006 -0.003 0.024 truck -0.010 -0.002 0.030 Source: Austrian Institute of Technology et al In a European study (Table 11) , researchers tied several pavement condition variables, including IRI, to fuel consumption. The coefficient of determination for each percentage increase in IRI to change in fuel consumption for cars and trucks ranged from -0.003 to -0.002. So, for every 1% improvement in IRI, fuel consumption improved by 0.0025 (averaged). The results concluded similarly to the Texas study outlined in (Table 10) : For say an IRI on Road A of 150 improved to a 100 using a use phase upgrade: 150 - 100 = 50 50 x 0.0025 = 0.125 or 12.5% So, the studies agree that ride quality has a tangible impact on mobile-sourced emissions and that for every 10 IRI, emission reductions for CO 2 and NO 2 might range from 2% to 3%. This would be substantial at scale as there are ~400 million cars and trucks operating in the United States. On balance, there is no question that agencies should use ride quality in assessing the environmental impact of paving quality, pavement condition over the lifecycle, and type of maintenance methods, procedures, and products used. Pavement maintenance methods and products should be evaluated based upon their ability to meet general lifecycle needs first, but also their ability to improve IRI within the context of the product’s net impact on emissions. Improving ride quality using products with high carbon intensity would prove counterproductive, of course. 195 The atomic mass of C is 12.01; nitrogen 14.01; and O 16.00. 196 Carlson A, Hammerstrom, and Eriksson O, Modeling Infrastructure on RoAd Vehicle Energy Consumption, ERA- NET ROAD, March 2013.