Contents lists available at ScienceDirect Transportation Research Part D journal homepage: www.elsevier.com/locate/trd The impact of airspace regulations on unmanned aerial vehicles in last-mile operation Mo Elsayed ⁎ , Moataz Mohamed Department of Civil Engineering, Faculty of Engineering, McMaster University, Hamilton, Ontario, Canada ARTICLE INFO Keywords: Unmanned Aerial Vehicles (UAV) UAV policy GHG emissions Autonomous drones Last-Mile delivery ABSTRACT Utilizing autonomous unmanned aerial vehicles (drones) in the last-mile delivery of parcels is regarded as the ultimate disruptive technology that might significantly reduce the GHG emissions in the freight sector. This study estimates the CO 2 e emissions for UAVs under different policies compared to diesel and electric ground delivery modes. First, the international UAV flight reg- ulations are synthesized and classified into three groups representing varying degrees of policy strictness. Second, utilizing real-word delivery demand data, full-day parcel-delivery operations of a three-digit postal code area in both urban and rural contexts are simulated for UAVs and ground delivery modes. The results show that in general, UAVs produce significantly lower emissions compared to ground delivery per parcel-km and up to 35% compared to electric ve- hicles. However, UAV emissions are highly dependent on the fuel mix used in electricity gen- eration. In urban contexts, UAV policy strictness can increase GHG emissions by up to 400%. 1. Introduction and background Battery-operated Unmanned Aerial Vehicles (UAVs) represent an affordable and sustainable aerial transportation system that is expected to significantly minimize the carbon footprint in cargo transport and parcel delivery (Mahony & Kumar, 2012; Colomina and Molina, 2014). In particular, UAVs are ideal for last-mile operation, which is expected to reduce delivery costs, emissions, and delivery time compared to light trucks and other traditional delivery methods. However, the viability of UAV operation hinges on the development of regulatory frameworks and civil flight policies. Our study aims at investigating the interlinked airspace regulations and its effect on environmental impact and the viability of UAV last-mile operations, which currently represents an understudied area. Furthermore, the study quantifies the GHG emissions, across different policies, resulting from daily last-mile operation through a developed simulation-based framework that could be readily applied to any UAV type and built context. Courier express parcel (CEP) delivery is expected to follow the e-commerce progression with a projected market share of 75%. The rapid growth rates (5.0%) between 2013 and 2017 motivated companies like Amazon, Google, and DHL to develop and test UAVs for parcel delivery (Heutger and Kückelhaus, 2014; Nieva and Rosenblatt, 2014). Teal Group forecasted that UAV spending would surpass the triple over the next decade, with cumulative worldwide expenditures exceeding $88.3 billion (Teal Group, 2019). However, companies anticipate a reduction in transportation costs, especially in urban operation, where they utilize fleets of small and low-altitude UAVs in densely populated cities. In such a context, autonomous UAVs fly through public spaces to deliver goods (Foina et al., 2015; D’Andrea, 2014). In this respect, UAV accidents such as severe lacerations, eye loss, and soft tissue injuries or property-damage represent a major roadblock. This is in addition to the expected liability hazards such as automobile accidents https://doi.org/10.1016/j.trd.2020.102480 ⁎ Corresponding author. E-mail address: archmsayed@gmail.com (M. Elsayed). Transportation Research Part D 87 (2020) 102480 1361-9209/ © 2020 Elsevier Ltd. All rights reserved. T