The Capacitated Open Vehicle Routing Problem (COVRP) is the open version of the Capacitated Vehicle Routing Problem (CVRP). In the COVRP, each route begins at the depot and ends at a customer.
In the reference given below, we presented the first exact optimization algorithm for the COVRP. Using this algorithm, we were able to solve to optimality the open version of a number of well-known CVRP instances.
The optimal solutions that we identified are given in a zip file which can be downloaded here. The zip file contains a separate solution file for each instance. Moreover, the zip file contains the file named "fileformat.txt" which explains the format of the individual solution files.
Reference:
A.N. Letchford, J. Lysgaard & R.W. Eglese (2007): "A Branch-and-Cut Algorithm for the Capacitated Open Vehicle Routing Problem", Journal of the Operational Research Society, vol. 58 (12), pp. 1642-1651. DOI