Freight transport, routing software and time-dependent vehicle routing models

Abstract

Routing and scheduling software is part of the Information and Technology systems available to support the transport industry, and uses complex algorithms along with geographical representations of the road network to allow better planning of daily collection and delivery schedules. This research reviews the evolution of routing and scheduling software, the algorithms used along with reported barriers to wider take-up and potential industry driven improvements that could be made. A survey of transport companies in the United Kingdom was conducted in order to validate and prioritize the software capabilities that require the most development according to the new challenges that the industry is facing. Responses suggested that companies required improved route optimization to tackle congestion based on time-dependent data and models, and greater accuracy in the representation of the road network. Not considering congestion leads to the underestimation of travel times and the production of inaccurate schedules. Literature shows that operational research techniques are available to solve problems that represent real world conditions, but research into the relative merits of using time-dependent models needs to be undertaken.

Although exact methods have been developed to solve the Vehicle Routing Problem, they cannot cope with large instances and rich variants that are required by the industry. Therefore, metaheuristic algorithms are usually implemented in routing software. A reported barrier in metaheuristic algorithms is the lack of accuracy (the difference between optimal or best-known values and the result of the proposed algorithm). In this research an algorithm was developed using elements of Large Neighbourhood Search that is capable to substantially improve the state of the art for the time-dependent Vehicle Routing Problem. Comparison of results with available test instances shows that the proposed algorithm is capable of obtaining a reduction in the number of vehicles (4.15%), travel distance (10.88%) and travel time (12.00%) compared to previous implementations in reasonable time. A variant that considers the Rules on Drivers’ hours required in the scheduling of vehicles over 3.5 tons in the European Union and the UK is also introduced. Analysis of results show result improvements in number of vehicles (19.0%), travel distance (17.7%) and route duration (4.4%) compared to previous implementations.

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Identifiers

ORCID for Ben Waterson: orcid.org/0000-0001-9817-7119

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