Anonymous public comment

I respectfully submit the following comment for your consideration. I feel that given the voluntary nature of the proposed survey, the sample pool and the resulting measurement of emissions may be skewed. Generally, respondents who possess resources to participate in a survey of this nature, and furthermore, is willing to have their equipment emissions measured on site, tend to be larger, established businesses, who operate fleets powered by newer, cleaner running diesel engines. In the construction industry, it is often the smaller operators, several tiers down in the contractor hierarchy, who, due to the marginal profitability of their enterprise, retain and operate older or grossly polluting equipment out of economic necessity. In order for the proposed ?real-world? emission test to be representative of the actual operating fleet, I strongly feel that an effort needs to be made to capture these smaller entitles in the your sampling, either through carefully weighing the size of the operators in your response pool, or through some other remedial measures that will account for these smaller, often higher polluting operators, who in the aggregate, may be responsible for a significant portion of pollutants from non-road diesel equipments.