Heavy-Duty Vehicle Activity Updates for MOVES Using NREL Fleet DNA and CE-CERT Data

Portable emissions measurement systems (PEMS) are used to perform in-use measurements for emissions inventory and regulatory applications. PEMS data represent real world conditions more accurately than chassis dynamometer or engine dynamometer testing, arguably being the most realistic method of determining exhaust emissions over a certain driving route. However, measured emissions and fuel consumption depend strongly on both the route followed and the traffic situation that the vehicle encounters. A tool for translation of emissions and fuel consumption between diverse types of vehicle activity is required. The purpose of this paper is to assess the possibility of using route-averaged properties (kinematic parameters) for translation of fuel consumption and NOx emissions for a set of eighteen heavy-duty vehicles operating over up to eight different driving routes. A linear model developed for heavy-duty vehicle chassis dynamometer data modeling has been extended to in-use heavy-duty vehicle data. Two approaches were implemented; the first approach mimicked the prior chassis dynamometer work by incorporating average vehicle speed and average positive acceleration and the second approach incorporated road grade in a characteristic power parameter. The end result is a simple method which was shown to be accurate for estimation of fuel consumption (within 5% relative error) and NOx emissions (within 12% relative error) for over-the-road vehicles over “unseen” roads or traffic situations, without the need to perform additional over-the-road tests.

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Spatial and Statistical Analysis of Commercial Vehicle Activity in Metropolitan Atlanta

Transportation Research Record Journal of the Transportation Research Board ◽

10.3141/1625-21 ◽

1998 ◽

Vol 1625 (1) ◽

pp. 165-172 ◽

Cited By ~ 3

Author(s):

Catherine Ross ◽

Randall Guensler ◽

Paula Stevens

Keyword(s):

Land Use ◽

Commercial Vehicle ◽

Temporal Data ◽

Heavy Duty ◽

Important Data ◽

Quality Models ◽

Heavy Duty Vehicle ◽

Vehicle Activity ◽

The Relationship ◽

Data Collection Effort

The next generation of air quality models demands a better understanding of medium- and heavy-duty vehicle activities and the relationship between these activities and emissions. Understanding fleet characteristics and their associated impact, therefore, is critically important. Data collected in a 1996 commercial vehicle trip survey for the Atlanta region are presented and analyzed. A survey data collection effort undertaken in 1996, which included the collection of data related to spatial, temporal, cargo, land use, and vehicle characteristics, is described. The results of a series of statistical analyses are reported and discussed. The results of geographic information systems analyses, which provide a spatial picture of commercial vehicle activity, are presented. The spatial analysis combines vehicle, cargo, and land use characteristics with spatial and temporal data within the study area. The results of this study provide a compelling snapshot of commercial vehicle activity in the Atlanta area.

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