The maxisum and maximin-maxisum HAZMAT routing problems

• We formulate and solve models for two new HAZMAT transportation route design problems for multiple origin destination pairs.
• The models minimize the danger to which vulnerable centers (schools, hospitals) are exposed by the routes.
• We propose a polynomial efficient heuristic for the problems.
• We apply the methods to actual data.

We design routes for transportation of hazardous materials (HAZMAT) in urban areas, with multiple origin-destination pairs. First, we introduce the maxisum HAZMAT routing problem, which maximizes the sum of the population-weighted distances from vulnerable centers to their closest point on the routes. Secondly, the maximin-maxisum HAZMAT routing problem trades-off maxisum versus the population-weighted distance from the route to its closest center. We propose efficient IP formulations for both NP-Hard problems, as well as a polynomial heuristic that reaches gaps below 0.54% in a few seconds on the real case in the city of Santiago, Chile.