High-occupancy Vehicle Research Articles

Multi-lane cellular automata model considering bus-HOV lane

To quantify the impacts of high occupancy vehicles (HOV) entering the exclusive bus lane on road traffic efficiency, the car following and lane changing characteristics of bus, HOV and non-HOV were analyzed when setting the bus-HOV lane. Using the theory of cellular automata (CA) and combining the control rules of the bus-HOV lane, the lane occupied by a vehicle and the type of a vehicle regarded as constraints were introduced into the asymmetric lane changing rules, and then a multi-lane CA model was established for the car following and lane changing of multi-type vehicles considering the bus-HOV lane. MATLAB software was used to accomplish numerical simulation to analyze the specific effects of the proportion of HOV, bus departure frequency and bus stop spacing on the traffic flow parameters and their relationships. The results show that: when the proportion of HOV is less than 0.5 on a three-lane road segment, setting the bus-HOV lane can not only improve road traffic efficiency but also ensure the speed of bus operation under the condition of high initial space occupancy; when the proportion of HOV exceeds 0.5 , it is difficult to improve road traffic efficiency by restricting non-HOV from entering the bus-HOV lane; when the initial space occupancy is greater than 0.2 , the higher the bus departure frequency is, the greater the decline of traffic volume of the bus-HOV lane is; when there are 5 bus routes to dispatch a bus every 3 minutes, compared with the low initial space occupancy, the traffic volume of the bus-HOV lane under the condition of the high initial space occupancy reduces by about 30%; the bus stop spacing more significantly affects the traffic efficiency of the bus-HOV lane, the longer the bus stop spacing is, the higher the frequency of HOV lane changing is, the more the increase of the congestion segments on the bus-HOV lane and the adjacent normal lane is, thus the traffic efficiency of the whole road is influenced.

Simulation Approach to Estimate the Potential of High-Occupancy Toll Lanes on German Freeways

This paper focuses on the potential of HOT lanes (high-occupancy toll lanes) in Germany. For this, various scenarios were defined and simulated on a synthetic road network that adheres to German guidelines. The results demonstrated that HOT lanes offered travel time advantages for carpoolers and HOT vehicles but led to longer travel times for single-occupancy vehicles and trucks. Scenarios with higher costs per kilometer generally reinforced the promotion of high-occupancy vehicles and encouraged a shift toward public transport. In contrast, low cost rates had a negative impact on the desired modal split, as the low cost of using the HOT lane became an incentive for comfortable HOT travel rather than carpooling or using public transport. With regard to CO2 and NOx emissions, we demonstrated the unexpected consequences of HOT lanes, when the general traffic flow worsened. In all scenarios, the emissions for both groups were consistently higher than in the baseline scenario without a managed lane, because of the reduced traffic flow. Overall, scenarios with higher costs per kilometer were more favorable in relation to emissions, as the displacement effect toward carpooling vehicles and public transport reduced the overall number of vehicles in the system. This issue may need to be addressed with the implementation of intelligent traffic management systems, especially those that can influence speed. Taking a comprehensive view of the results, HOT lanes in Germany offer the potential for improving traffic conditions and optimizing modal split. However, the limitations of their application must be taken into account.

Exploring the willingness to pay for high-occupancy toll lanes under conditions of low familiarity

This study evaluates details of a progressive transportation development model, wherein high occupancy vehicle (HOV) lanes are transformed into high-occupancy toll (HOT) lanes. Although the management strategy of HOT lanes has been implemented for many years, the implementation of HOT lanes is limited in many regions, and thus, many people remain unfamiliar with the concept. This study aims to evaluate travelers' willingness to pay for HOT lanes based on a “low application” scenario in Shenzhen, China, wherein some HOV lanes are present and may potentially be transformed into HOT lanes, but not all area residents are aware of their intended purpose. According to the Diffusion of Innovation Theory, we leverage this situation to conduct a survey of perceptions and attitudes toward the HOT lanes and evaluate how these perspectives may translate to HOT lane utilization. We further proposed a hybrid utility and regret model considering the impacts of loss aversion caused by tolls or coordinated carpooling for single occupancy vehicles to explore relationships between travel behavior and surveyed demographic and socio-economic characteristics in the context of HOT lanes in places where they are unfamiliar. A sensitivity analysis is conducted to characterize any apparent changing influences. The results show that the model considering decision regret performs well, especially in the scenario with low tolls. Nearly 80% of travelers are willing to pay tolls for HOT lanes, even with limited prior exposure to the concept. The increased acceptance of HOT lanes can be expected to hurt total toll revenue, which may be triggered by easier access to carpool partners associated with the free pass. The study informs a deeper understanding of travelers’ willingness to pay for HOT lanes and helps policy-makers develop differentiated tolling strategies.

An overview of dynamic pricing toll roads in the United States: Pricing algorithms, operation strategies, equity concerns, and funding mechanism

Toll roads with fully dynamic pricing schemes could play a key role in addressing the economic and environmental tolls imposed by increasing congestion levels in major metropolitan areas. Transportation professionals usually argue that they could provide additional revenue streams to accelerate the delivery of much-needed highway projects and serve as a tool for travel demand management. However, the number of dynamic pricing toll roads only increased recently in the U.S., and their performance has not been empirically evaluated systematically. This study provides a comprehensive review of U.S. dynamic pricing toll roads. Pricing is reactive to demand, and additional travel demand management strategies such as incentives for high occupancy vehicles, clean vehicles, and transit are commonly included. Both conventional project delivery methods and private–public partnerships have been used for such projects. Financial statements from a few P3 dynamic toll road projects suggest they are taking full advantage of TIFIA loans and are performing well during their short history. Equity issues are commonly raised, and many projects address them specifically through subsidies to vulnerable groups or re-investment in the community. Further quantitative analyses are needed to test if dynamic toll roads are an efficient tool to address the financial, economic, and environmental challenges major metropolitan areas face.

Assessing the impact of ride-sourcing vehicles on HOV-lane efficacy and management strategies

High-occupancy vehicle (HOV) lanes, which exclusively allow vehicles with two or more travelers on board to enter, has been recognized as a promising and practical way to motivate travelers to carpool. However, in the presence of ride-sourcing services, ride-sourcing vehicles with one driver and one (or more) passenger on board also meet the vehicle requirements of HOV lanes. So instead of encouraging travelers to carpool, HOV lanes may benefit ride-sourcing users and stimulate ride-sourcing demand. In this paper, in a single-corridor network with both HOV lanes and general purpose (GP) lanes, we model travelers’ mode choices among transit, driving alone, ride-sourcing, and carpool, and delineate travelers’ lane choices at user equilibrium, with the travel time of GP/HOV lanes and the carpool price being endogenously determined. With numerical examples, we show that the occupation of HOV lanes by ride-sourcing vehicles will greatly reduce the time saving on HOV lanes, thus lower the attractiveness of carpool, and increase the total travel time cost on the corridor. To solve this problem, we propose to implement an additional tolling scheme on HOV lanes, so that carpool users can split the toll evenly, while ride-sourcing riders have to pay the toll alone. As shown by numerical examples, the optimal tolling scheme can effectively reduce the occupancy of ride-sourcing vehicles on the HOV lane and encourage users to carpool. And the impacts of the ride-sourcing price, driving car cost and the HOV lane capacity ratio on the effectiveness of the proposed hybrid toll and HOV strategies are examined through sensitivity analysis.

Routing of multi-modal autonomous vehicles for system optimal flows and average travel cost equilibrium over time

In the emerging era of autonomous vehicles (AVs), an important question is how to integrate AVs in a multi-modal framework. Recent studies on Transportation Management Centres (TMCs) for future AVs addressed the issue of providing system optimal (SO) solution. However, none of them considered the possibility of developing a multi-modal SO-based solution. In this regard, we propose a novel multi-modal Transportation Management Centre (MMTMC) for future AVs, which controls both the routing and mode use of each traveller and distributes the AVs in such a way that SO flows are maintained for the whole network every day, while travellers on the same origin-destination (OD) have the same Multi-modal Average Travel Time (MMAVT) over a cycle or period of time (in days). That is, travellers on the same OD may encounter different travel times or costs on different days, but over the planning cycle of many days, their travel times will all average to be the same MMAVT, hence preserving the MMAVT equilibrium. Travellers will travel on single occupancy vehicles (SOVs) or high occupancy vehicles (HOVs) on different routes for different days within the planning cycle, while maintaining the same MMAVT overall for the cycle. Travellers on SOVs will experience no crowdedness while on HOVs will experience crowdedness. We model both the cases of minimum system time and minimum system cost (including crowdedness cost), and provide link-based solution first for both cases. For minimum system time, we apply the conventional Frank Wolfe algorithm to generate feasible link flows, whereas for the minimum system cost problem, we incorporate a sensitivity-based equilibrium procedure to derive the SOV, HOV link flows and demand profiles. Afterwards, we utilize the most likely path method to compute unique SOV and HOV path flows and solve the MMAVT equilibrium. Then, we investigate the case of mixed-equilibrium (ME), where some travellers are given the option not to subscribe to the MMTMC and do their own private routing, i.e. user equilibrium (UE) travellers, who are penalized by a toll. The tolls imposed on these MMTMC non-subscribers are defined by the travel time/cost difference between the MMAVT of subscribers and UE users based on their value-of-time (VOT) distribution. This study investigates the properties of this MMTMC routing pattern, the relationship between MMAVT, tolling, and SOV and HOV market penetration, which offers insights to integrate AVs in a multi-modal framework.

Simulating the performance of HOV lanes for optimal urban traffic management

Traffic congestion is a significant problem in crowded cities, resulting in increased travel times, air pollution, and reduced productivity. High-occupancy vehicle (HOV) lanes have emerged as a promising solution to tackle these issues. HOV lanes are reserved for vehicles carrying multiple passengers, incentivizing shared travel and reducing the number of low-occupancy vehicles on the road like school buses. By reducing the overall number of cars on the road, HOV lanes can significantly alleviate traffic congestion, improve travel times, and reduce air pollution. The effectiveness of HOV lanes depends on the degree of demand for shared travel and the availability of incentives, such as employer-provided benefits or toll exemptions. Additionally, the design and implementation of HOV lanes must be carefully planned to ensure that they do not negatively impact other road users. Tehran, as one of the largest and most populous cities in Asia, is a major destination for daily travel by workers. The Tehran-Karaj freeway serves as the primary and busiest entrance to Tehran city, experiencing heavy traffic every day in the morning towards Tehran and in the evening towards Karaj. In this study, the traffic conditions of this freeway were simulated in the existing state and with the presence of HOV lanes, and the resulting traffic parameters were compared and analyzed under different traffic scenarios. The findings of this research can offer valuable insights for decision-makers and traffic policy makers.

Determining the factors affecting transportation demand management and selecting the best strategy: A case study

Demand management in transportation services, as well as demand sustainability, demand planning, and demand implementation are critical components in service quality and environmental sustainability. It is evident that developing a transportation system, particularly one responsive to society’s aspirations and demands, will result in long-term and sustainable success for enterprises. Transportation demand management and strategies can produce alternative perspectives at a desirable and sufficient level to handle problems in the field while considering the obstacles. Considering the elements influencing transportation demand management in logistics enterprises, this study aims to evaluate factors affecting transportation demand management and select the best strategy. The study was carried out on logistic firms with a corporate identity in the Turkish province of Samsun (Turkiye), engaged in international transportation activities to define the criteria affecting transportation demand management and select the best transportation demand strategy. The constituents from the literature review were analyzed using the q-rung orthopair fuzzy MCDA methodology. “Freight Transportation” was determined to be the most crucial measure affecting transportation demand management, while “Competition Legislation and Regulations Regulation” was the least important factor. The rapid expansion in the number of companies participating in freight transport and their capacity was evaluated as the essential aspect for the relevant logistics companies in transport demand management. The “Strategy for Prioritizing High Occupancy Vehicles” is the best transportation strategy based on the weights of the transportation demand management factors. Because of the implementation of this strategy in logistics organizations, this study is regarded as a significant indicator of competitiveness to ensure efficiency and effectiveness. The defined transport demand strategy also represents an exemplary model of the measures that need to be developed to increase the demand preference for sustainable transport.

Case Study Evaluation of a New Approach to Price Metropolitan Highways for Congestion Relief, Sustainability and Equity

This paper addresses the practically important challenge of devising efficient and politically feasible congestion pricing policies in the context of metropolitan highways. Congestion on metropolitan highways continues to grow while governments struggle to fund alternative modes of travel. The purpose of this paper is to explore the viability of a new approach to address highway congestion while also accommodating the mobility needs of those who don’t drive. It involves creating congestion-priced lanes on limited access highways without adding new lanes. The lanes would be taken from general use and reserved for high-occupancy vehicles (HOV), transit vehicles and toll-payers, with cash rewards paid to HOV and transit users to attract solo drivers to shared travel. Variable tolls charged to lower-occupancy vehicles on the dedicated lanes would limit traffic demand on the lanes, keep traffic flowing, and fund the cash rewards. Rewards would be high enough to attract a sufficient number of drivers to ride as passengers instead so that congestion would be eliminated on the toll lanes and reduced on the remaining toll-free lanes through mode shifts. The policy-level analysis using a real-world case study of a radial highway segment with directional peaking suggests that this congestion pricing/cash rewards strategy could generate surplus revenues and provide financial support for bus rapid transit operating on the congestion-free lanes.

Examining the Safety Impacts of High-Occupancy Vehicle Lanes: International Experience and an Evaluation of First Operation in Israel

Current transport policies promote better use of existing roadways by using traffic management strategies such as high-occupancy vehicle (HOV) lanes. International experience showed positive mobility impacts of HOV lanes, while research evidence on their safety implications is limited. In Israel, the first HOV lanes were introduced in 2019. This study examined the impacts of HOV lanes on road safety based on a detailed review of international research and accident analyses, which evaluated the safety effects of HOV lanes in Israel. The literature survey applied a systematic screening of research studies from the past two decades and found that HOV lanes were frequently associated with an adverse effect on road safety. Yet, findings were limited to the North American experience, with mostly left-side HOV lanes in use, while in Israel, right-side HOV lanes were introduced. In Israeli evaluations, before-after comparisons of accident changes with comparison groups were applied, with regression models fitted to monthly time series of 17 accident types. Results showed that HOV lanes’ operation led to increasing accident trends, particularly in interchange areas and in the daytime. In injury accidents on road sections, an average increase of 31–41% was found (yet non-significant), while at interchange areas, an increase was even higher and sometimes significant. Thus, adverse safety effects should be expected and accounted for in future planning of HOV lanes. Further research should explore the design features of HOV lanes to reduce their negative safety implications.

Highway Managed Lane Usage and Tolling for Mixed Traffic Flows with Connected Automated Vehicles and High-Occupancy Vehicles

This paper investigates managed lane toll setting and its effect under mixed traffic of connected automated vehicles (CAVs), high-occupancy vehicles (HOVs), and human-driven vehicles (HDVs), with the goal of avoiding flow breakdown and minimizing total social cost. A mesoscopic finite difference traffic simulation model considers the flow–density relationship at different CAV market penetration rates, lane-changing behaviors, and multiple entries/exits, interacting with a reactive toll setting mechanism. The results of Monte Carlo simulation suggest an optimal policy of untolled HOV/CAV use with tolled HDVs in particular scenarios of limited CAV market penetration. Small and targeted tolling avoids flow breakdown in managed lanes while prioritizing HOVs and other vehicles with high values of time. Extensions of the formulation and sensitivity analysis quantify the benefits of converting high-occupancy HDVs to CAVs. The optimal tolling regime combines traffic science notions of flow stability and the economics of resource allocation.

Travel mode preference in Addis Ababa, Ethiopia: empirical observations

ABSTRACT This research paper analyzes urban travel mode preference in Addis Ababa using a survey distributed to 457 public transit users. The article highlights the details of individual travel and then discusses the implications of the travel patterns for transport policy in the city. The study employed percentages and run multinomial logistic regression to analyze the relationship between mode choice, travel characteristics and socio-economic features of individuals. In terms of mode choice and the influential factors, the analysis shows that income, age, travel expenditure and distance are the determining factors that affect mode choice. It was also found that the privately owned public transport, Taxi (mini-bus) and Higer (midi-bus) form the dominant mode of transport used by closely half percent (41.3%) of the survey respondents. On the basis of our analysis, we suggest that policies have to be devised to make government owned public transport service better in order to support a shift from using low occupancy vehicles to high occupancy vehicles which ultimately solve the problem of congestion and environmental pollution.

Some like it HOT: The racialization of mobility, the racial tax state, and silence in managed lane conversions

ABSTRACT Transportation in the United States is a deeply and intricately racialized system. In this paper, we use Seiler’s ideas regarding the racialization of mobility and Henricks and Seamster’s theory of the racial tax state, in conjunction with Presser’s analysis of the unsaid, to explain high-occupancy vehicle (HOV) to high-occupancy toll (HOT) lane conversions in U.S. metropolitan areas. We argue that silence on race in the major push for HOV to HOT lane conversions by libertarian “think tanks” and U.S. Department of Transportation guidance is fundamental to instrumentalizing transportation policy for racist tax regimes.

Relieving Traffic Congestion and Accommodating Travel Growth without Expanding Highways: A Policy Evaluation for the Eastern Segment of the Capital Beltway

This paper evaluates a congestion management concept involving conversion of two existing general-purpose freeway lanes per direction on an 8-lane freeway (with 4 lanes per direction) to priced lanes offering free access for high-occupancy vehicles, in conjunction with cash payments to incentivize a sufficient number of commuters to travel as passengers in transit, carpools or vanpools such that congestion on the remaining free lanes would be no worse than it was before the conversion. Building on prior research, we use a refined modeling process to explore the viability of implementation of the concept on the eastern segment of the Capital Beltway in the Washington, DC metro area. The results of the analysis suggest that the strategy can benefit users of shared travel modes and toll-payers, improve travel speeds on toll-free general-purpose lanes, generate significant surplus revenues to support capital investments and operating subsidies for shared travel modes, and can absorb traffic growth through 2040.

Tunnel bottleneck management with high-occupancy vehicle priority on intelligent freeways

Abstract Tunnels on freeways, as one of the critical bottlenecks, frequently cause severe congestion and passenger delay. To solve the tunnel bottleneck problem, most of the existing research can be divided into two types. One is to adopt variable speed limits (VSLs) to regulate a predetermined speed for vehicles to get through a bottleneck smoothly. The other is to adopt high-occupancy vehicle (HOV) lane management. In HOV lane management strategies, all traffic is divided into HOVs and low-occupancy vehicles (LOVs). HOVs are vehicles with a driver and one or more passengers. LOVs are vehicles with only a driver. This kind of research can grant priority to HOVs by providing a dedicated HOV lane. However, the existing research cannot both mitigate congestion and maximize passenger-oriented benefits. To address the research gap, this paper leverages connected and automated vehicle (CAV) technologies on intelligent freeways and develops a tunnel bottleneck management strategy with a dynamic HOV lane (DHL). The strategy bears the following features: 1) enables tunnel bottleneck management at a microscopic level; 2) maximizes passenger-oriented benefits; 3) grants priority to HOVs even when the HOV lane is open to LOVs; 4) allocates right-of-way segments for HOVs and LOVs in real time; and 5) performs well in a mixed-traffic environment. The proposed strategy is evaluated through comparison against the non-control baseline and a VSL strategy. Sensitivity analysis is conducted under different congestion levels and penetration rates. The results demonstrate that the proposed strategy outperforms in terms of passenger-oriented delay reduction and HOVs' priority level improvement.

Exploring Whether Managed Lanes Contribute to the Wide Adoption of the Connected and Autonomous Vehicles

The rapid development of connected and autonomous vehicle (CAV) technology and the outperformance of the managed lane have drawn increasing attention with respect to wonder whether the CAV operating in the managed lane is helpful. Therefore, this study focuses on the methodology applied to explore whether the managed lane is beneficial in the gradual application of CAVs. Three managed lanes are considered, namely a bus lane, CAV dedicated lane, and high-occupancy vehicle lane. Given the unfamiliarity with the travel mode related to CAVs, the attitudinal variables for CAVs and their influencing relationship are designed and quantified by a structural equation model based on the extended technology acceptance model. A two-level nested logit model with different types of managed lanes as explanatory variables is further developed to analyze the travel choice of traditional modes and CAV modes. The difference in probabilities of travel choices under managed lanes is also explored. The results indicate that the three managed lanes have a positive influence on promoting the adoption of the CAV modes, with an increase of at least 13.5% shifted from traditional modes in the conventional lane. Moreover, the influences of managed lanes differ between transit CAVs and non-transit CAVs. The probabilities of choosing transit CAVs under three managed lanes increase in the range of 12.9%–27.2%, while those of non-transit CAVs only show a maximum 6.5% increase in the CAV dedicated lane. The study is expected to assist in designing differentiated development of CAVs with the deployment of managed lanes.

Preferences for zero-emission vehicle attributes: Comparing early adopters with mainstream consumers in California

Ambitious zero-emission vehicle (ZEV) adoption goals have been proposed to decarbonize the transportation sector, while the current market share pales in comparison. Although the distinct socio-economic characteristics of ZEV early adopters relative to mainstream car buyers are well understood, the two groups' preferences for ZEV attributes are not clear. This knowledge gap hinders the development of effective policies to achieve mass ZEV penetration goals. This paper examines consumers’ preferences and willingness to pay for ZEV attributes based on 755 early adopters and 3493 mainstream consumers from the 2019 California vehicle survey data. Results show that early adopters are more sensitive to battery range, acceleration performance, home charging availability, and high occupancy vehicle lane access, while mainstream consumers attach greater importance to cost attributes (e.g., fuel and maintenance costs) and charging time. Moreover, the effects of monetary incentives are found to be significant for both groups, whereas neither early adopters nor mainstream consumers value the availability of public charging stations. The findings of this study inform targeted ZEV policymaking and marketing strategies in different adoption stages.

IMPACT OF MARKET PATRONAGE ON THE TRAFFIC SITUATION IN BENIN METROPOLIS, NIGERIA

This paper examines the influence of market patronage on the traffic situation in Benin City, Nigeria. Nine market routes were studied, and a well-structured questionnaire administered randomly and systematically was used to collect data from 407 respondents. Descriptive and correlation techniques were used to analyse the responses. Most of the markets were found to be situated along transit routes, and operated every day, resulting in street trading and parking which contributed 76.2 percent to the traffic situation in Benin metropolis. It is suggested that traffic laws prohibiting street trading and parking be enacted and enforced. The marketplaces should be restructured to accommodate motor parks, and alternative routes to bypass market areas for non-market trips should be considered as well as the provision of priority lanes for High Occupancy Vehicles (HOV).

Urban Air Pollution and Greenness in Relation to Public Health.

Air pollution is the result of economic growth and urbanization. Air pollution has been progressively recognized as a serious problem for cities, through widespread effects on health and well-being. There is less concern from stakeholders about greenness and air pollution mitigating factors in an urban area. This research targeted to indicate the spatial dissemination of greenery, air quality levels (PM2.5, PM10, CO2, and AQI), and exposure to air quality-related health risks for the people in the urban area. The data were collected by measuring air quality at transportation stations and manufacturing industries with Air visual pro, then observing and mapping greenness in the city within the administrative boundary by GIS (street greenery, forest, availability of greenness in the manufacturing industry), and lastly questionnaire and interview were employed for air quality-related health issues. Then, the air quality data were analyzed by using USAQI standards and health messages. Both quantitative and qualitative research approach had employed to explore air pollution levels, availability of greenness, and air quality-related health issues. Moreover, Health questionnaires and greenness were correlated with air quality levels by a simple linear regression model. The result indicated that there was unhealthy air quality in the transportation and manufacturing industries. The measured air quality showed in a range of 50.13-96.84 μg/m3 of PM2.5, 645-1764 ppm of CO2, and 137-179 Air quality index (AQI). The highest mean of PM2.5 and air quality concentrations at Addis Ababa transportation stations and manufacturing sites ranged between 63.46 and 104.45 μg/m3 and 179-326, respectively. It was observed with less street greenery and greenness available in residential, commercial areas, and manufacturing industries. The pollution level was beyond the limit of WHO standards. The result has shown a health risk to the public in the city, particularly for drivers, street vendors, and manufacturing industry employees. Among 480 respondents, 57.92% experienced health risks due to air pollution by medical evidence. High health risks due to industries and old motor vehicles in the city need to be reduced by introducing policies and strategies for low-carbon, minimizing traveling distance, encouraging high occupancy vehicles, and promoting a green legacy in the street network and green building.

A Framework to Determine the Utilization of Vacant Taxis on HOV Lanes with the Optimal Deployment

For the purpose of determining whether vacant taxis are supposed to use high-occupancy vehicle (HOV) lanes, this paper builds a framework to explore the performances of a network before and after vacant taxis use HOV lanes and to detect the optimal deployment of HOV lanes. We use a variational inequality (VI) to describe travelers’ mode choice following a logit model and the route choice abided by the user equilibrium principle on the network. A simple network is adopted to explore the network performances when vacant taxis are allowed to use/forbidden from using HOV lanes. Then we propose a framework presented by a bi-level model for the optimal deployment of HOV lanes in which the lower level is the variational inequality and the upper level aims at maximization of social welfare. This bi-level programming with a genetic algorithm combined with a surrogate assistant approach is applied to the simple network and a Sioux Falls network to analyze the network performances in the cases allowing/forbidding vacant taxis from using HOV lanes. The results reveal the paradox that social welfare may decrease when allowing vacant taxis to use HOV lanes compared to when forbidding vacant taxis from using HOV lanes. Considering optimal HOV lane deployment, this paradox still exists. However, it does not always happen due to the different parameters, e.g., flag–fall price. Therefore, the qualification of vacant taxis to use HOV lanes depends on the topology, attributes, and travel demand of the network. The results display that the models and the algorithm are effective in reality.