Table 2.

Heuristic methods for solving VRP in emergency relief proposed in recent studies.

Study	Algorithm	Purpose	Approach	Merit
Duque et al. [58]	Iterated Greedy-randomise constructive procedure (IGRCP)	For scheduling and routing of a repair crew after a disaster	Based on the GRASP meta-heuristic method with multiple runs of the construction phase plus improvement routine	Overcomes the problem size limitation of dynamic programming and solves medium- to large-scale instances efficiently
Fontem et al. [59]	Decomposition-based method	To solve the Emergency Open Routing under Stochastic Travel Times and Deadlines (EORSTTD) Problem for quick relief during emergency	Renders the EORSTTD problem tractable by formulating a counterpart problem, and decomposes it into two sub-problems	Produces a solution that enables flexible decisions to be made according to the decision-maker's preference to avoid the risk of deadline violation
Osman and Ram [60]	Centralised Point-to-Point Look-Back (C-PTPLB)	To find evacuation routes from an urban building and out of its predetermined neighbourhood	Based on looking back from intermediate destination nodes at a current time T, and identifying the objects that can be point-to-point routed to reach there precisely at time T from preceding nodes	Provides point-to-point optimal route schedules while minimising the number of iterations when compared with other methods
Bruni et al. [19]	Iterated Greedy method	For routing of vehicles carrying critical supplies and to disaster victims	Implements an adaptive local search procedure and a destroy procedure to enable extensive searching for a solution space where near-optimal solutions can be employed	Flexible and applicable to various risk measures, can provide good solutions quickly
Faiz et al. [61]	Column generation and Path generation algorithm	For vehicle routing operations during a humanitarian crisis	Devises a task adjacency graph for a path-based integer linear program, using a column generation framework to solve large-scale instances	Outperforms the exact method (traditional arc-based mixed integer linear program) in solution time without sacrificing solution quality
Moreno et al. [62]	Branch-and-Benders-cut, construction and local search heuristics	To solve the Crew Scheduling and Routing Problem in road restoration after disasters	Decomposes an integrated problem into a master problem with scheduling decisions and sub-problems with routing decisions	Provides feasible solutions and optimality gaps where instances cannot be solved utilising exact methods