The optimum strategy for mode choice modelling of interregional fish transport considering shippers' heterogeneity

The determinants of mode choice of interregional transport of fish, which is highly perishable, vastly differ from that of other commodities. These determinants are to be identified to improve transport efficiency. A questionnaire survey of shippers is used to collect the data. Highly correlated observed variables are combined to form four latent factors by factor analysis to reduce the errors in modelling. Logical relations among the component variables of latent factors are perceived, and mathematical formulations are used to estimate new variables. It is found that transportation costs and shipment weight contributes to factor 1, while distance contributes to factor 2. However, transportation costs are associated with distance and shipment weight. Thus, the variable, transportation cost per q-km, is estimated. Survey respondents' attitudes are also incorporated into modelling by including qualitative factors obtained by the factor analysis of shippers' preference ratings. A latent class analysis confirmed the existence of heterogeneity among ship-pers. Misrepresentations of effects occur in modelling if the heterogeneity in the data is not considered. No studies have found the best combination of observed variables, latent factors, estimated variables, and qualitative factors, consider-ing shippers' heterogeneity in freight mode choice. Hence, this study is done to find the optimum modelling strategy. Modelling revealed that models built with estimated variables outperformed those built with latent factors. Including qualitative factors along with observed variables and estimated variables showed further improvement. However, the model that includes observed variables, estimated variables, and qualitative factors considering shippers' heterogenei-ty is the best. It was found that the mode selection behaviour of different latent classes of shippers is distinct. A mode shift from road to rail could be achieved by lowering transportation costs and increasing speed, reliability, and safety for fish transport. Expanding roll on–roll off facilities, dedicated freight corridors, parcel trains, refrigerated contain-ers, and piecemeal service by rail promote a mode shift from road to rail and reduce energy usage.

