April 26, 2019

New Relationship Models between Vehicle Speed Profile, Roadway Characteristics, Pavement Roughness, and Vehicle Operating Costs

Sponsor: U.S. DOT, FHWA DTFH61-14-C-00044 Enhanced Prediction of Vehicle Fuel Economy and Other Vehicle Operating Costs

Time

1:40pm - 3:00pm

Location

1605 Tilia, Room 1103, West Village

Speaker(s)

Elie Hajj, Associate Professor, Civil and Environmental Engineering & Associate Director of WRSC, Pavement Engineering & Science Program, University of Nevada

Abstract

Considerable changes in vehicle technology over the past several decades resulted in
an emerging need for improved fuel and non-fuel vehicle operating costs (VOCs) estimations for
use in benefit-cost analyses. One of the key tasks for improving VOC estimations is to develop
representative vehicle dynamic models and then simulate their operation over different road
conditions using driving cycles (i.e., speed-time profiles) that represent real-world conditions.
As part of this study, 4,400 Naturalistic Driving Study trips collected at 6 sites and around
12,500,000-second truck data were used for driving cycle’s development. A total of 652 unique
driving cycles were generated for different scenarios of full access control (FAC) and partial or
no access control (PNAC) facilities.

Thirty vehicle dynamics computer simulation models from subcompact cars to fully loaded class
8 tractor–trailer trucks were built and verified. Gasoline, diesel, E85, and LNG fueled vehicles
were included in the fleet, as well as HE. Each vehicle model was simulated over the developed
driving cycles and respective highway grades (upslope and downslope) and curvatures to predict
fuel economy for different scenarios of FAC and PNAC facilities. Fuel economy prediction
models capable of estimating fuel consumption for each vehicle over a range of average speed,
road grades, and curvatures were developed.

The effects of pavement roughness on vehicle fuel consumption were evaluated and new models
were developed and verified. Four non-fuel VOCs (tire wear, oil consumption, mileage-related
vehicle depreciation, and repair and maintenance) models were also developed for different
vehicle types, traffic conditions, and highway design scenarios as defined by roadway properties
such as speed limit, curvature, grade, and pavement roughness.

Biographical Sketch

Dr. Elie Hajj is an Associate Professor in the Civil and Environmental Engineering Department and an Associate Director of the Western Regional Superpave Center (WRSC) at University of Nevada, Reno. He has over 16 years of experience in academia and industry with an emphasis on sustainability of pavement systems and dynamic response of pavement structures. Dr. Hajj authored over 100 publications in journals, national and international conferences, and technical reports. He made more than 100 presentations in professional meetings, conferences, and workshops. He served as a principal investigator on multiple projects for FHWA, FAA, State DOTs, local governments, etc.

Dr. Hajj is currently chairing TRB AFK50 committee and a member of the ASCE, Association of Asphalt Paving Technologists, and the International Society for Asphalt Pavements. He is a founding member and an elected officer (since 2017) for the international Academy of Pavement Science & Engineering (APSE). Dr. Hajj is also an associate editor for the International Journal of Pavement Engineering-IJPE.