Push forward insertion heuristic for initial solution

Last week i read the publication “A Hybrid Genetic Algorithm, Simulated Annealing and Tabu Search Heuristic for Vehicle Routing Problems with Time Windows” to understand, how an initial solution for VRPTW problem can be defined, but i don’t understand the usefulness of polar coordinate angle pi in the function Cost of Ci " -α d0i + βli + γ((pi/360)d0i) ", also how the weights for the three criteria α,β and γ were defined.

I desperately seeking this answer, if you can help me,

Waiting for reply,