Yunfei Fang

Optimal Lane Reservation in Transportation Network

This work studies a lane reservation problem in a transportation network. It aims to design task paths and optimally select lanes to be reserved in a transportation network. In this problem, each lane has limited residual capacity, which is the lane capacity that can be used for the tasks causing no delay in this lane. If the residual capacity of a lane is not large enough to allow tasks to use it, the reservation of this lane is necessary. Once reserved, the lane can be used by the tasks only. Therefore, the travel time in this reserved lane is less than that when it is not reserved. Such lane reservation strategy ensures that each task can transport the commodity from its source to destination within a given travel time. However, this reserved lane generates traffic impact on nonreserved lanes. The objective of the problem is to minimize the total impact of all reserved lanes on nonreserved lanes subject to the timely completion of all the concerned tasks. In this paper, two integer linear programming models are, for the first time, formulated. The complexity of the problem is demonstrated to be non-deterministic polynomial-time hard. Then, an optimal algorithm based on the cut-and-solve method is developed for the problem. The computational results of randomly generated network instances up to 120 nodes and 468 arcs show that the proposed algorithm significantly outperforms the direct use of an optimization solver of CPLEX.

A cut-and-solve-based algorithm for optimal lane reservation with dynamic link travel times

This paper investigates an optimal lane reservation problem with dynamic link travel times via a lane reservation strategy. This strategy is to select some existing general-purpose lanes from a transportation network and convert them to reserved lanes for some special road users only so that a time-guaranteed transportation can be ensured. However, such conversion may cause traffic impact such as an increase of link travel times on adjacent lanes due to the disallowing utilisation of reserved lanes by general-purpose vehicles. Thus, the considered problem aims to design reserved lane-based paths for the time-guaranteed transportation with the objective of minimising the total traffic impact caused by the conversion. Different from lane reservation problems with constant link travel times in the literature, the considered problem assumes dynamic link travel times, which is proved NP-hard. The problem is initially formulated as a mixed integer non-linear programming model. In order to solve it, the non-linear model is reformulated as an equivalent linear model and a cut-and-solve-based algorithm is proposed to obtain optimal solutions. Experimental tests on randomly generated instances show that the overall performance of the proposed algorithm outperforms a direct use of a commercial CPLEX MIP solver.

Iterative algorithm for lane reservation problem on transportation network

In this paper, we study an NP-hard lane reservation problem on transportation network. By selecting lanes to be reserved on the existing transportation network under some special situations, the transportation tasks can be accomplished on the reserved lanes with satisfying the condition of time or safety. Lane reservation strategy is a flexible and economic method for traffic management. However, reserving lanes has impact on the normal traffic because the reserved lanes can only be passed by the special tasks. It should be well considered choosing reserved lanes to minimize the total traffic impact when applying the lane reservation strategy for the transportation tasks. In this paper, an integer linear program model is formulated for the considered problem and an optimal algorithm based on the cut-and-solve method is proposed. Some new techniques are developed for the cut-and-solve method to accelerate the convergence of the proposed algorithm. Numerical computation results of 125 randomly generated instances show that the proposed algorithm is much faster than a MIP solver of commercial software CPLEX 12.1 to find optimal solutions on average computing time.

An efficient two-phase exact algorithm for the automated truck freight transportation problem

A recent study has developed an integer linear program and an exact algorithm for the automated truck transportation freight problem with lane reservation. However, due to its NP-hard nature, their proposed method becomes difficult to solve large-size problems within acceptable time. In this paper, we firstly present an improved integer linear program by adding valid inequalities and identify that its several special cases are classical combinatorial optimization problems. Based on analyzed properties, a new efficient two-phase exact algorithm is developed. Computational results on benchmark and new larger-size instances with up to 700 nodes and 55 tasks show that the new algorithm outperforms very favorably the state-of-the-art one.

Exact and Heuristic Algorithms for Rapid and Station Arrival-Time Guaranteed Bus Transportation via Lane Reservation

This paper addresses a new lane reservation problem called bus lane reservation problem (BLRP). The focus of the problem is on optimally selecting lanes to be reserved from an existing transport network and designing reserved lane-based bus paths, such that the rapid and station arrival-time guaranteed bus transit can be ensured, thereby achieving rapid and reliable bus transportation. However, once lanes are reserved, negative impact, such as an increase in travel time on adjacent non-reserved lanes may be caused. For this problem, an improved integer linear program is first formulated to minimize such negative impact. As the existing commercial solvers, e.g., CPLEX, can only solve small-size problems, we develop an exact enhanced cut-and-solve algorithm and an improved kernel search heuristic for solving medium- and large-size problems. Results of extensive numerical experiments confirm the effectiveness and efficiency of the proposed algorithms. In addition, a bi-objective robust BRLP is investigated to study the tradeoff between the negative impact of reserved lanes and the robustness of solution against the uncertainties in the link travel time and the bus dwell time.

The capacitated lane reservation problem in transportation network

This paper investigates a capacitated lane reservation problem in a transportation network. The problem is to decide the task paths and select lanes to be reserved in a capacitated network to ensure that each commodity can be transported from its source to destination within a given travel time, meanwhile the lanes capacity is not violated. Its objective is to minimize the total impact of all reserved lanes on other normal lanes. To solve this problem, two integer linear programming models are formulated. The complexity of the problem is proved to be NP-hard. Then an algorithm based on a cut-and-solve idea is proposed to obtain optimal solutions. To evaluate the performance of our proposed algorithm, numerical experiments of randomly generated instances are conducted. Computational results show our algorithm significantly outperforms a well-known optimization software package CPLEX.

A new cut-and-solve and cutting plane combined approach for the capacitated lane reservation problem

A transportation planning problem via lane reservation is studied.An exact approach based on cut-and-solve and cutting plane method is developed.Separation algorithms are proposed to find valid inequalities for cutting plane method.Computational results show the approach is efficient compared with IP solver CPLEX. This paper investigates a capacitated lane reservation problem with residual capacity. The focus of the problem is to design time-guaranteed paths for a set of transportation tasks via lane reservation with respect to the residual capacity issue. The lane reservation can ensure the time-guaranteed travel but has negative impact on the normal traffic. Thus, the objective of the problem is to minimize the impact of such lane reservation by optimally selecting lanes in the network to be reserved. For this NP-hard problem, an exact approach based on the cut-and-solve and cutting plane methods is developed. New separation algorithms are proposed to find appropriate valid inequalities according to the characteristic of the problem to accelerate the optimal convergence of the resolution approach. Numerical computational results show that the developed approach is efficient as compared with state-of-the-art algorithms in the literature and the IP solver CPLEX.

A new model for lane reservation problem with time-dependent travel times

This paper studied an optimal lane reservation problem with time-dependent link travel times. It aims to design time-guaranteed paths by converting some existing general-purpose lanes to reserved lanes with the objective of minimizing the total traffic impact of reserved lanes on general-purpose lanes. The traffic impact is caused by reserved lanes because they can be used by some special road users only and the adjacent general-purpose lanes may be more congested. The considered problem is to NP-hard. We propose a new mixed integer nonlinear programming model and transform it to an equivalent tractable linear model. We propose a cut-and-solve based algorithm in which new strategies are developed for generating piercing cuts. Computational results show that it is much more efficient to solve the proposed new model in the paper than the model in the literature and the overall performance of the proposed algorithm outperforms a direct use of an optimization solver of CPLEX on randomly generated instances.

Lane Reservation Problem with Time-dependent Travel Times

Abstract This paper presents an mixed integer nonlinear programming formulation for the lane reservation problem with time-dependent travel times. It aims to design time-guaranteed paths for some transportation tasks via lane reservation strategy, which is to optimally select and reserve some lanes for the use of the tasks with the objective of minimizing the total traffic impact caused by the reserved lanes. The considered problem is NP-hard. The original nonlinear model is transformed into an mixed integer linear program and a cut-and-solve based algorithm is proposed to obtain optimal solutions. Experimental tests on randomly generated instances show that the overall performance of the proposed algorithm outperforms a direct use of an optimization solver of CPLEX.

A tabu search based algorithm for optimal lane reservation

This work studies a transportation problem called as lane reservation problem, which is to complete some special transportation tasks within pre-given deadline by optimally selecting lanes to be reserved from the network and designing source-destination paths for the special tasks. Because of the exclusive use of the reserved lanes by the special tasks, negative impact such as increase of travel time on adjacent general-purpose lanes is caused on normal traffic. Then, the objective of the lane reservation problem is to minimize the total negative impact caused by the reserved lanes. To solve this problem, a tabu search based algorithm is developed. Numerical computational results on randomly generated instances show the efficiency of the proposed algorithm compared with a referenced IP solver CPLEX 12.5.