term represents the total length of tours performed by couriers to visit pickup/delivery locations, and the second term represents the detours (out and back) performed between access hub $l$ and its neighboring access hubs.\
The cumulative time (in time-courier) necessary to perform courier tours is based on the approximation in (\[VRPCouriers\]) as follows: $$\label{courier time cumulative}
T^C_{l}(\tau, \omega) = (\rho_{l}^P(\tau,\omega) + \rho_{l}^D(\tau,\omega))(\frac{ k^C(\delta_{l})^{-\frac{1}{2}}}{s^C} + t^C_a) + \sum_{a \in A_{pool}((l)} n_{a}^C(\tau, \omega)(\frac{2 d_a}{s^C_0} + t^C_a) + (\rho_{l}^D(\tau,\omega) + \rho_{l}^P(\tau,\omega))t^C_u$$ where the first term represents the travel time between pickup/delivery locations at a speed of $s^C$ and the stopping time $t_a^C$ per stop, the second term represents the travel time during detours to neighboring access hubs at a speed of $s^C_0$ plus a stopping time $t_a^C$, and the third term represents the service time (handling) $t_u^C$ per pickup and delivery.\
Thus, the cost associated with couriers’ operations at access hub $l$ in period $\tau$ under scenario $\omega$ is: $$C^C_{l}(\tau, \omega) = ((\rho_{l}^P(\tau,\omega) + \rho_{l}^D(\tau,\omega))k^C(\delta_{l})^{-\frac{1}{2}} c^C_v + \sum_{a \in A_{pool}(l)} (2 n_{a}^C(\tau, \omega) d_a) c^C_{v_0}) + T^C_{l}(\tau, \omega) c^C_w$$ where the first term represents the variable travel costs, respectively $c^C_v$ between pickup/delivery locations and $c^C_{v_0}$ between access hubs, and the second term represents 