Hai-jun Huang
Beihang University, School of Economics and Management, Faculty Member
This paper investigates the efficiency and equity of morning peak ramp control schemes in a freeway corridor with limited capacity. In terms of efficiency, both short-run and long-run optimal ramp control schemes are obtained by... more
This paper investigates the efficiency and equity of morning peak ramp control schemes in a freeway corridor with limited capacity. In terms of efficiency, both short-run and long-run optimal ramp control schemes are obtained by minimizing the total travel cost and maximizing the total social benefit along the corridor. It is found that for a short-run optimum with inelastic demand, the morning peak period is of the same duration for different on-ramp locations. But for a long-run optimum with elastic demand, the peak duration for various on-ramps increases with the local capacity elasticity of demand. In terms of equity, two measures are defined from a demand-based viewpoint and a space-based viewpoint. It is shown that the short-run optimal ramp control scheme is perfectly fair from a demand-based equity viewpoint. Consequently, two typical ramp control schemes—a perfect demand-based equity scheme and a perfect space-based equity scheme—are introduced and compared with the long-ru...
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This paper makes a contribution to the literature by bounding the travel time inefficiency of the logit-based stochastic user equilibrium (SUE) under Advanced Traveler Information Systems (ATIS). All drivers are divided into two groups,... more
This paper makes a contribution to the literature by bounding the travel time inefficiency of the logit-based stochastic user equilibrium (SUE) under Advanced Traveler Information Systems (ATIS). All drivers are divided into two groups, one equipped with ATIS and another without, and both of which follow the logit-based SUE principle in making route choices. The equipped drivers have less degree of travel time variability than the unequipped ones. The inefficiency of the two-user class SUE is defined in two different ways, i.e., in comparison with the SO in terms of total actual system travel time, or in comparison with the corresponding SSO in terms of total perceptive system travel time of all users. The effects of various parameters on the bounds are further investigated. It is found that the inefficiency bound against the SSO is only dependent upon the degree of link congestion and independent of the network topology. In contrast, besides the effect of the degree of link congest...
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This paper investigates how the local authorities could efficiently regulate the public transit, which is operated by a private firm. Both the waiting time at stops and the in-vehicle congestion costs are taken into account to reflect the... more
This paper investigates how the local authorities could efficiently regulate the public transit, which is operated by a private firm. Both the waiting time at stops and the in-vehicle congestion costs are taken into account to reflect the transit service quality. The Pareto-efficient frontier is derived and three types of regulation strategies, namely Price-cap, Return-on-output and Quantity control, are analyzed and compared. On one hand, although the Price-cap regulation can attract more demand effectively, the private firm will inefficiently supply a lower frequency to keep the cost down. On the other hand, both the Return-on-output (ROO) and Quantity-control regulations are Pareto efficient that can keep the transit system operating along the Pareto-efficient frontier. Especially, Quantity-control regulation seems to be more attractive than ROO as there is no need for the firm’s accounting information. In addition to the investigations on regulation, a new optimal demand-frequen...
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In this paper, we study various parking management schemes in a many-to-one network, where each origin is connected to the destination by a highway with a bottleneck and a parallel transit line. First, we derive a model to compute the... more
In this paper, we study various parking management schemes in a many-to-one network, where each origin is connected to the destination by a highway with a bottleneck and a parallel transit line. First, we derive a model to compute the morning commuting pattern when the destination has inadequate parking space to accommodate potential private cars. Second, we propose and compare the following three schemes of distributing parking permits to commuters residing in different origins: uniform, Pareto improving, and system optimum distribution of parking permits. Third, free trading of parking permits among commuters in a free market is introduced to better cater for commuters' parking needs. Numerical examples show that parking permits distribution and trading are very efficient in traffic management.
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We study the properties of traffic flow coming from free flow to congested flow on a two-lane road by using cellular automaton traffic model. A new boundary condition is proposed, which exhibits the reason of the relation that traffic... more
We study the properties of traffic flow coming from free flow to congested flow on a two-lane road by using cellular automaton traffic model. A new boundary condition is proposed, which exhibits the reason of the relation that traffic flow against on the injected probability. The simulation results show that the traffic never comes into congestion even if there are
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ABSTRACT In this paper, we study various parking management schemes in a many-to-one network, where each origin is connected to the destination by a highway with a bottleneck and a parallel transit line. First, we derive a model to... more
ABSTRACT In this paper, we study various parking management schemes in a many-to-one network, where each origin is connected to the destination by a highway with a bottleneck and a parallel transit line. First, we derive a model to compute the morning commuting pattern when the destination has inadequate parking space to accommodate potential private cars. Second, we propose and compare the following three schemes of distributing parking permits to commuters residing in different origins: uniform, Pareto improving, and system optimum distribution of parking permits. Third, free trading of parking permits among commuters in a free market is introduced to better cater for commuters' parking needs. Numerical examples show that parking permits distribution and trading are very efficient in traffic management.
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It is well known that the use of advanced traveler information systems (ATIS) can alleviate traffic congestion and enhance the performance of road networks through guiding commuters' route and departure time choices. It has also been... more
It is well known that the use of advanced traveler information systems (ATIS) can alleviate traffic congestion and enhance the performance of road networks through guiding commuters' route and departure time choices. It has also been recognised that ATIS can help destination and activity choices in determining why, where and when various activities are engaged in. This pa- per attempts
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In this work, a type of the evolution network is constructed in the evolution process of traffic flow. We study the influence of the traffic dynamics on the structural properties of the evolution network, and measure the probability... more
In this work, a type of the evolution network is constructed in the evolution process of traffic flow. We study the influence of the traffic dynamics on the structural properties of the evolution network, and measure the probability distributions and scaling properties of the network. The traffic dynamics is simulated by using the city traffic model [i.e., the modified ChSch
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Advanced Traveller Information Systems (ATIS) are generally expected to be efficient in reducing travel time and parking search time uncertainties. This article presents a mixed-behaviour multi-class equilibrium model for investigating... more
Advanced Traveller Information Systems (ATIS) are generally expected to be efficient in reducing travel time and parking search time uncertainties. This article presents a mixed-behaviour multi-class equilibrium model for investigating heterogeneous drivers’ responses to route guidance and parking information systems in stochastic and time-dependent networks. The proposed model simultaneously considers the drivers’ choices of departure time, route and parking location
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ABSTRACT Based on the characteristics of car-following behavior in a road traffic system containing signal light, we improve the car-following equation and then present a traffic flow model which considers the signal light influence.... more
ABSTRACT Based on the characteristics of car-following behavior in a road traffic system containing signal light, we improve the car-following equation and then present a traffic flow model which considers the signal light influence. Numerical results show that the model can reproduce such phenomena as flow clustering and dissipating, and capture the propagation of stopping and starting waves. It is concluded that the model proposed in this paper is reasonable.
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In the previous studies of congestion pricing, it is assumed that the network is managed by a central authority with the objective to enhance the performance of the whole network. In practice, however, a transportation network often... more
In the previous studies of congestion pricing, it is assumed that the network is managed by a central authority with the objective to enhance the performance of the whole network. In practice, however, a transportation network often covers multiple administrative regions, and the subnetwork in each local region is managed separately by the local transportation authority with perhaps competing objectives.
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Based on the property of heterogeneous traffic flow, we in this Letter present a new car-following model. Applying the relationship between the micro and macro variables, a new dynamic model for heterogeneous traffic flow is obtained. The... more
Based on the property of heterogeneous traffic flow, we in this Letter present a new car-following model. Applying the relationship between the micro and macro variables, a new dynamic model for heterogeneous traffic flow is obtained. The fundamental diagram and the jam density of the heterogeneous traffic flow consisting of bus and car are studied under three different conditions: (1) without any restrictions, (2) under the action of the traffic control policy that restrains some private cars and (3) using bus to replace the private cars restrained by the traffic control policy. The numerical results show that our model can describe some qualitative properties of the heterogeneous traffic flow consisting of bus and car, which verifies that our model is reasonable.
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ABSTRACT When the microscopic pedestrian models, in which pedestrian space is continuously represented, are used to simulate pedestrian movement in the buildings with internal obstacles, some issues arise and need be dealt with in detail.... more
ABSTRACT When the microscopic pedestrian models, in which pedestrian space is continuously represented, are used to simulate pedestrian movement in the buildings with internal obstacles, some issues arise and need be dealt with in detail. This paper discusses two of the issues, namely formulating the desired direction of each pedestrian in the buildings and determining the region around each pedestrian, other individuals and obstacles in which affect his or her movement. The methods for computing the desired direction and effect region are proposed, using the algorithms for the potential of pedestrian space. By numerical experiments, the performance results of three proposed formulae for the desired direction are compared, the method for the effect region is tested, and the validity of the method for computing the desired direction as considering the border effect of obstacles is verified. Numerical results indicate that the proposed methods can be used to formulate pedestrian movement, especially in the buildings with internal obstacles, in the microscopic models with continuous space representation.