The planning horizon is set as 24 hours and all customers' time windows are scaled accordingly by the coefficient 24/b_0. 
In other words, if [a_i,b_i] is the time window of customer i in a original Solomon instance, 
[a_i 24/b_0, b_i 24/b_0] is customer's i time window in the modified instance. 
Moreover, distances are scaled by a coefficient of 3.5, meaning that the distance between two customers i and j 
in the modified instance is d'_{ij}=3.5d_{ij}, where d_{ij} is the distance between i and j in the original instance. 
The maximum payload is set to 2,000 kg and the demand of each customer is multiplied by 10. Furthermore, service time is set to 
1.5 hours for all customers. .