Evaluation of the Traffic Impacts of Mass Evacuation of Halifax: Flood Risk and Dynamic Traffic Microsimulation Modeling

Abstract

This paper presents a comprehensive evaluation of traffic impacts of a mass evacuation of the Halifax Peninsula under several flooding scenarios. Flood extent and associated damages to the transport network are identified through digital elevation modeling that intersects with the Halifax stream and transport networks. The resulting flood scenarios inform a traffic microsimulation model that uses a dynamic traffic assignment-based microsimulation approach and simulates the evacuation of 34,808 evacuees estimated from the Halifax Regional Transport Network Model. The simulation results suggest that flooding of the links by 7.9 m flood reduces alternative evacuation routes by 31.2%. It takes 15 hours to evacuate 83% of evacuees while the remaining 17% are not accommodated in the network due to reduced network capacity. The number of vehicles in the network has peaked at 13,000 in this flooding scenario. An evaluation of network performance reveals a sustained congestion prevailing from 4th to 7th hour of the evacuation. The novelty of this study is that it develops a comprehensive tool of flood risk and dynamic traffic microsimulation modeling to offer an in-depth evaluation of potential impacts during evacuation. The results will help emergency professionals in evacuation planning and making emergency decisions.

Optimal Evacuation Strategy for Parking Lots Considering the Dynamic Background Traffic Flows

“…It was found that vehicles’ departure rate of every exit is mainly dependent on the time headway of the background traffic flows on the road connecting the exit of the parking lot. We also know that the dynamic distribution of background traffic flows in the evacuation road network influences the optimal evacuation routes greatly; this observation is in line with the study of Alam et al [49]. Additionally, to our knowledge, the method proposed in this research is an optimization model with minimum evacuation time, which is also applicable in the vehicle evacuation problems of other infrastructures, e.g., tunnels and bridges.…”

Development of a Multimodal Microsimulation-Based Evacuation Model

“…There is considerable marine movement through Halifax Harbor, located alongside the peninsula. Furthermore, Halifax is on a hurricane path that has previously caused devastation, as demonstrated in Alam et al (15). In 2003, Hurricane Juan made landfall in the Halifax Regional Municipality, causing eight fatalities.…”

Vulnerability Assessment during Mass Evacuation: Integrated Microsimulation-Based Evacuation Modeling Approach

“…. To obtain the zonal clearance time, a microsimulation model developed by Alam et al is updated and utilized to simulate evacuation scenarios (24). The ''clearance time'' required to evacuate each zone on the Peninsula is determined through the simulation.…”

“…These studies combined activity-based models with traffic simulation models. One of the current authors’ earlier contributions also developed a sequential modeling framework that includes a flood risk model, a regional transport network model, and a traffic microsimulation model ( 24 ). However, vulnerability assessment requests the distribution of population in different time periods, which is absent within these sequential evacuation modeling frameworks.…”

“…However, vulnerability assessment requests the distribution of population in different time periods, which is absent within these sequential evacuation modeling frameworks. This research aims to fill the gap by combining an integrated urban systems model and the sequential modeling approach that offers reliable information on the condition of flood flows, demographic changes, network disruptions, and traffic patterns for the vulnerability assessment ( 24 ).…”