Review Driving Cycles for Estimating Vehicle Emission Levels and Energy Consumption Amanuel Gebisa 1 , Girma Gebresenbet 2, *, Rajendiran Gopal 3 and Ramesh Babu Nallamothu 1   Citation: Gebisa, A.; Gebresenbet, G.; Gopal, R.; Nallamothu, R.B. Driving Cycles for Estimating Vehicle Emission Levels and Energy Consumption. Future Transp. 2021, 1, 615–638. https://doi.org/10.3390/ futuretransp1030033 Academic Editor: John Graham Received: 11 October 2021 Accepted: 25 October 2021 Published: 1 November 2021 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Mechanical Systems and Vehicle Engineering Department, Adama Science and Technology University, Adama P.O. Box 1888, Ethiopia; amanuel.gebisa@astu.edu.et (A.G.); ramesh.babu@astu.edu.et (R.B.N.) 2 Head of Division of Automation and Logistics, Department of Energy and Technology, Swedish University of Agricultural Science, P.O. Box 7032, 750 07 Uppsala, Sweden 3 Department of Motor Vehicle Engineering, Defence University-College of Engineering, Addis Ababa P.O. Box 1041, Ethiopia; razaautoirtt@gmail.com * Correspondence: girma.gebresenbet@slu.se; Tel.: +46-18-671901 Abstract: Standard driving cycles (DCs) and real driving emissions (RDE) legislation developed by the European Commission contains significant gaps with regard to quantifying local area vehicle emission levels and fuel consumption (FC). The aim of this paper was to review local DCs for estimating emission levels and FC under laboratory and real-world conditions. This review article has three sections. First, the detailed steps and methodologies applied during the development of these DCs are examined to highlight weaknesses. Next, a comparison is presented of various recent local DCs using the Worldwide Harmonized Light-Duty Test Cycle (WLTC) and FTP75 (Federal Test Procedure) in terms of the main characteristic parameters. Finally, the gap between RDE with laboratory-based and real-world emissions is discussed. The use of a large sample of real data to develop a typical DC for the local area could better reflect vehicle driving patterns on actual roads and offer a better estimation of emissions and consumed energy. The main issue found with most of the local DCs reviewed was a small data sample collected from a small number of vehicles during a short period of time, the lack of separate phases for driving conditions, and the shifting strategy adopted with the chassis dynamometer. On-road emissions measured by the portable emissions measurement system (PEMS) were higher than the laboratory-based measurements. Driving situation outside the boundary conditions of RDE shows higher emissions due to cold temperatures, road grade, similar shares of route, drivers’ dynamic driving conditions, and uncertainty within the PEMS and RDE analysis tools. Keywords: driving cycle; emissions; PEMS; real driving emissions (RDE) 1. Introduction Exhaust emissions from vehicles present a serious risk in urban areas, affecting air quality and human health [1]. Vehicle emissions are influenced by on numerous issues such as driving style, traffic congestion, emission control devices, vehicle performance, fuel quality, and ambient operating conditions [2]. The DC has been defined by various authors as “a series of data points representing speed versus time, and gear selection as a function of time, speed versus distance in a specific region, or a part of a road segment” [3] and “a speed-time profile for a study area within which a vehicle can be idling, accelerating, decelerating, or cruising” [4]. The most important functions of vehicle driving cycles are to determine emission levels and FC [4,5], evaluate vehicle performance [6], estimate driving style [7], and simulate driving circumstances on a laboratory chassis dynamometer (CD) [8], which provides the basis for vehicle design [9]. For electric vehicles, the driving range calculation and state of charge estimation are generally performed on the basis of the standard driving cycle [9]. Future Transp. 2021, 1, 615–638. https://doi.org/10.3390/futuretransp1030033 https://www.mdpi.com/journal/futuretransp