Review of traffic demand management strategies

This review article seeks to determine the most effective strategies to reduce traffic congestion which have been implanted in different countries and cities around the world. In this review, previous research work was gathered focusing on approaches for mitigating traffic congestion issues. The paper discovered that there are two ways to control congestion which are through supply-side actions, and demand-side actions, the paper also discovered that traffic modelling and simulation software packages are crucial to decision-makers because of its capability to evaluate and simulate the effects of any suggested improvements or strategies to reduce traffic congestions for a certain street network and for a whole city.


Introduction
All facets of a city's economic and personal life are impacted by traffic the mismatch issue is how the traffic issue is often regarded between demand and supply i.e., the capacity of road travel needs etc. when this discrepancy widens the city officials have made an effort to strike a balance by creating infrastructures such as new roads or capacity expansion or changes in policies such as prohibiting automobile movement during big events in the city [1].When the transportation system cannot meet the current needs traffic jams result and lead to negative effects including higher delay, pollution, and fuel wastage taking care of the traffic for transportation planners the issue presents a dilemma because due to the limited options and rising traffic demand to develop more capability [2].Traffic Congestion has many various manifestations, occurs in a variety of settings, and is brought on by a variety of mechanisms [3], a several direct reasons of congestion, such as too many vehicles for the capacity of an intersection or a certain route, as well as dynamic modifications in highway capacity caused by lane-changing and following-car behavior.Additionally, they are inextricably tied to other unrelated variables including area economic dynamics, job trends, income levels, trends in car ownership, and land use patterns [4].Traffic management is frequently discussed as part of a planned strategy to make sure that drivers follow the law.Some see it is both traffic enforcement of laws and rules and traffic policing and monitoring, the regulation, coordination, and supervision of traffic on a specific network, such as a citywide, residential sector, neighborhood, etc., are the goals of traffic management.This is done to ensure smooth traffic flow, lessen jams and delays, increase roadway capacity, and most importantly, minimize traffic accidents [5].

Aim and Objectives
The prime objective of this review article is to address and provide a detailed explanation of the most effective strategies to mitigate traffic congestion.Also, identified traffic demand management strategies contribute to reducing delay, fuel consumption, CO emissions, and improve the selected network level of service.

Literature Review
Many studies that dealt with traffic congestion in cities around the world were conducted by the application of various strategies, and different techniques to solve traffic problems.This section reviews some of the conducted work in this field, hoping that soon adopting some of these strategies to mitigate current horrible congestion problem in most Iraqi cities.
To solve the problems of traffic management in Mehdipatnam city networks, a model that had been built using VISSIM.Rearranging the bus terminal, banning U-turns, improving junctions, and signalizing crossings are some of the recommended solutions.The effectiveness of public transit has been evaluated separately.The reduced wait times, shorter lines, and fewer delays show how successful the recommended solutions are [6].
As potential solutions to easing Dhaka's traffic congestion, multiple market-and nonmarket-based transport demand management techniques were proposed.According to the report, increased transportation options alone will not be sufficient to meet urban people's growing desire for travel.The report emphasizes that market-based methods, such as pricing policies and Applied TDM programs, have promising futures and that the appropriate authorities should make the required preparations to enable their quick implementation [7].
The increased ownership of vehicles in Bulawayo, It was investigated how the second-largest city in Zimbabwe is influencing the smooth flow of traffic [8].The study looked at the ways in which traffic management techniques can increase traffic flow, relieve congestion and pollution, creating a conducive environment for work and travel that supports sustainable development in developing nations.It also looked at how traffic impacts the environment and how the harm can be minimized.According to the study's findings, Bulawayo is seeing an increase in automobile ownership.
Increasing road capacity and improving public transportation are the key techniques used by the City authorities in Dar es Salaam City to regulate traffic, according to [9].Due to several factors, including the rapid growth of the existing Central Business District, the absence of use of physical design as a crucial strategy for decreasing traffic congestion, the rapid growth in both the people and the number of cars, and these factors along, these strategies have not produced the desired results.Both strategies of increasing road capacity, enhancing public transportation, and physical design should be utilized in tandem for the present solutions to function more efficiently and sustainably.
A study of the traffic characteristics on rural multi-lane highways was presented [10].In this inquiry, empirical data from study locations along the four-lane divided agricultural highway between Cairo and Aswan were employed.It was discovered that the lane position significantly affects both traffic stream relationships and average travel speed.Finally, lane position and traffic volume greatly influence headway characteristics.
According to [11], an urban environment is not the best place for electric vehicles.Additionally, discussed how to employ socio-technical experiments and transitions theory to make electric vehicles a competitive alternative to the existing automobility system.The conclusion is that, as prospective areas from which broader socio-technical change may emerge, sub-urban and rural electric vehicle uses should receive more policy and academic attention.Based on case study data from electric car trials conducted as part of the ENEVATE research program into owners of such vehicles in Northwest Europe, this result was reached.
The GreenWave technique of managing traffic lights, which enables one direction traffic to proceed through a sequence of junctions without being halted by a red signal, was discussed by [12] and suggested combining the route guiding technique GreenDrive with a traffic signal control technology called GreenSwirl.Traffic lights are managed by GreenSwirl to ensure a smooth flow of traffic as they turn green successively and along nonstop circular paths across the city.Thus, the GreenWave technology is expanded.SUMO, a traffic simulation packages, and the network system on Manhattan Island were utilized in a simulation Using navigation technology to improve overall traffic management in the city.This technique reduces travel time by 10%-60% on average.
An adaptive traffic control system that runs, manages, and controls signalized junctions with/without cooperation was described by [13].ISBAK Inc. in Turkey created the adaptive traffic control system known as ATAK.The ATAK system was identified in this study as a traffic control device for signalized junctions.The system's performance was described.The ATAK system's use at isolated and coordinated intersections revealed that cycle time performance improvements are around 10% and trip time improvements are about 15%.
Reduced modeling effort was highlighted by [14] while keeping the advantages of time-dependent traffic congestion modeling.Grouping streets was suggested while taking into consideration actual traces depicting traffic patterns.The efficiency of this guideline was evaluated for the Valencia city in Spain, and the findings indicate that to lessen the quantity of traffic patterns necessary while still meeting the essential criteria for time-dependent modeling by a factor of 4210.
According on data acquired by continuous counting stations, [15] presented average daily traffic volume and annual truck traffic.Data from 4 weights in motion (WIM) stations put on Latvian highways were used, totaling 8,186,871 cars or 1989 days.According to the findings, truck traffic varies greater than ordinary traffic throughout the year, particularly during holidays.Regular traffic has more differences between counting points than truck volume.The results explained that despite the time of year when counting is made has a greater impact on truck traffic than short-term counting results if components from inadequate permanent counting sites are used to correct short term counting findings.
Livingston Avenue is a large arterial corridor that provides access to the city center in New Brunswick, New Jersey.[16] Conducted a cost-benefit study of a road diet for Livingston Avenue.The prices also reflect the lengthened travel times brought on by the capacity drop.They were represented by a simulation of the street created with VISSIM.Road diet conversions of arterial roads in urban areas will reduce accidents by around 19%, according to research on the safety effect.Based on the expense of travel time compared to the worth of statistical life saved, the advantages of collision reductions and the costs of additional delays were assessed.Robustness tests were performed for a variety of different circumstances.Results show that over a 20-year period, benefits vastly outweigh expenses.
Research by [17] examined whether the capacity of the already available rest facilities on federal roads was adequate to accommodate both the present and future demand for truck stops.First creating a model, then utilizing information from the BR-101 Federal Highway in Santa Catarina State, Brazil, to validate it.Tests conducted utilizing a portion of the data acquired (part of which underwent statistical analysis) produced good findings, demonstrating that the demand behavior was consistent with both what was seen in the field and what truck drivers said when interviewed.All data still must be processed, and the study needs to be replicated in other areas with various features.
To investigate better options to promote public transportation use, a study by [18] examined Travel Demand Management Strategies to raise the mode share of public transportation through psychosocial factors, travel chain features, quality of life, and travel behavior.According to the study's findings, TDM must be used effectively if there is to be an increase in public transportation usage Quality of life, psycho-social issues, and trip chain qualities need to be taken into consideration while attempting to influence people's travel behavior in order to promote using more public transportation and to decrease single-occupant vehicle (SOV) use.
To manage traffic based on pollution levels, model the road infrastructure, and generate suggestions for road users, [19] developed a comprehensive and flexible approach to issue solving strategy involves calculating the impact of road networks' the state of the air index and producing suggestions for rerouting traffic to improve the air quality on the roads.Contextual data and historical and current pollution records are used to do this.Using the Hadoop MapReduce architecture and the Dijkstra method, the road network's shortest route was looked for.The performance of the suggested system has been greatly enhanced using the techniques for data retrieval and analysis using the Hadoop framework.
A framework for traffic management and ITS applications in metropolitan settings was given by [20] to assist handle the regional traffic issues.Based on experience from throughout the world, eleven viable ways to achieving sustainability in traffic management are developed.The study's conclusions indicated that an essential part of intelligent transportation systems (ITS's) contribution to the implementation of several of these strategies for traffic sustainability.Specific metrics for each method must be developed based on the local circumstances.
A study by [21] investigated how traffic mix affected the capacity of India's divided four-and sixlane highways.The impact of each vehicle type on the highway's capacity is assessed.Five categories were used to group all the automobiles on a roadway: normal cars, large cars, heavy truck, and both powered two-and three-wheeled vehicles.Utilizing capacity as the performance indicator, the VISSIM software is calibrated and utilized to produce traffic operations based on field data.The percent proportion of big cars, heavy trucks, and motorized three-wheelers in the traffic stream was shown to decrease highway capacity, but the percent percentage of motorized two-wheelers in the traffic stream increased it.
In order to evaluate the impact of the motorbike ban, [22] proposed creating a system for forecasting traffic demand that combines trip models, car ownership data, and traffic assignment models.Then, by comparing several scenarios for 2013 and 2035, the anticipated effects of the motorcycle prohibition were calculated.According to the findings, the prohibition would be able to cut down on kilometers of traffic and vehicle miles driven in 2013 by roughly 18.0 and 26.9 percent, but only 4.5 and 6.0 percent in 2035.Alternatively put, the restriction considerably lessens the present challenges with urban mobility.
The impact of access management systems on safety performance was studied by [23].The findings indicated that while segment length and average daily traffic (ADT) impacts are often constant and uniform among collision types, there is heterogeneity in the safety performance of horizontal alignment, access control techniques, and vehicle types.Greater shares of truck traffic are consistently shown to be related with higher head-on accident rates, while the coefficient for the fraction of motorized two-wheelers is found to be random for rear-end incidents.Although median opening presence is found to increase both rear-end and head-on collisions, the effect on total crashes is random, even if portions with service lanes are linked with less of these crash categories.
According to [24], the ITS application looks to be offering solutions for traffic management and control that are promising.A successful model may be created through an integrated approach using a variety of sensors and technology, and was based on global best practices seen in nations like the USA, Dubai, Canada, the UK, etc.However, every technology has its own drawbacks.There are several physical, social, and economic obstacles in the way of ITS's effective growth in a nation like India.Numerous government entities in India have taken the initiative to execute various ITS initiatives as part of the "Smart City" project.
The use of two demand management strategies-car-free days and odd-even parking meters-to reduce traffic and pollution in Bandung, Indonesia, was explored by [25].The program SATURN traffic network modeling has been used to forecast the route preferences of vehicles.Results showed that both odd-even plate and car-free day policies had unexpected consequences that reduce their efficacy but, if addressed, might transform them into very advantageous solutions.The Odd-Even plate was very effective at first, but as drivers start to adapt by purchasing a second vehicle or even using fake number plates, the performance gradually declines.Car-free days reduced traffic flow levels in the scheme but diverted the vehicles congestion/pollution to other routes.
In the framework of EU transport policy, [26] proposed the idea of transportation demand management (TDM), the causes of difficulties with transport intensity, and effective ways to lower transportation demand.The study revealed the societal awareness of mobility management, which helped identify the main issues with transportation demand that cities are experiencing.From this vantage point, it is evident that Poland has one of the highest rates of transportation in comparison to the length of its roadways.It also revealed that the major drivers of suburbanization are frequently the present urban policy.
A study by [27] suggested that the majority of traffic management challenges be addressed empirically rather than in a formal manner in order to achieve coordinated control on roadways.The paper proposed a quick and accurate technique for anticipating network control actions impacting traffic based on a variety of scientific simulation and modeling models at the micro level.
In Patna, Bihar, India, [28] created a guideline for calculating the level of service of safety (LOSS) of two-lane rural highways using just the road geometry and roadside characteristics.With the use of this recommendation, LOSS may be evaluated even in the absence of systematic crash history databases, traffic exposure models, or prediction algorithms.
On the federal route in Siberia, [29] addressed the approaches that are currently used to anticipate traffic intensity.Results of calculations made using the suggested methodology and empirical dependency, generated using data from detectors on traffic intensity showed high convergence with actual traffic intensity levels.Therefore, in areas with low road density, the resultant empirical dependency may be used to estimate the volume of traffic on dead end suburban roadways everyday.The low labor effort and potential automatization of the suggested approach are two benefits to be mentioned.As regards drawbacks, the approach cannot be used in the highly developed transportation network typical of the Russian Federation's European Region.
A study by [30] provided as a research location, a study focused from Qatar's capital city of Doha, was employed.Along with information on pedestrians and vehicles, the actual disputes in the real world were observed and noted.Using VISSIM microsimulation software, the analyzed junction was modeled and calibrated while the trajectories of cars and pedestrians were created.The simulated trajectories were then analyzed using the Surrogate Safety Assessment Model (SSAM) to find any possible conflicts in the research region.The findings suggested that prospective conflicts might be foreseen with reasonable certainty.Additionally, the results of scenario testing may be utilized to analyze the effects of geometric enhancement.in minimizing possible conflicts while microsimulation is utilized to forecast the location of conflicts and the results to discover how geometric progress affects lowering possible conflicts.
A study by [31] investigated the connection between several urban traffic congestion-related parameters and the level of traffic in Polish cities.These statistical techniques included regression analysis and correlation.They concluded that demand-side factors are more important in Polish cities than supply-side factors, or perhaps the current transportation policy is ineffective, based on the most statistically significant correlations between the number of business entities and the number of passenger cars that occurred in this case.These tools can help reduce congestion in several ways, i.e., by putting into practice several sub-objectives, such as lowering the demand for travel, reducing the usage of automobiles, enhancing the efficiency of public transportation, and improving the way the infrastructure is used.
By choosing two little business districts with roughly there are the same number of establishments, one of which is in Troy, New York, while the other is in New York City using models to calculate the overall amount of cargo and service traffic produced at these locations, [32] assessed the parking needs of business activities related to freight and services.The authors then calculated the quantity of parking spots needed under various demand management assumptions using various estimations of how long these cars stay at a parking spot.The findings demonstrate that parking requirements are inversely correlated with typical parking times.In general, parking requirements increase with duration.
In their study, [33] examined the use of Transportation Demand Management (TDM) strategies to lessen traffic in metropolitan areas and enhance Level of Service (LOS).The circumstances at the junction, which connects two major arterial streets in Amman, Jordan, were examined using Synchro 8 software.There was a noticeable decrease in delay and fuel usage, however, there was little improvement in LOS.When traffic demand was lowered by 20% and capacity was raised with 6 lanes on each approach under the current conditions, the LOS was improved.For the following five years, it was found that there would be an approximate 64 percent and 63 percent reduction in fuel usage and delay, respectively.
The issue of congestion was addressed by the introduction of Transportation Demand Management (TDM) solutions by [34].TDM promotes the use of mass transit and buses as alternatives to private automobiles for transportation.The walled city of Jaipur is examined in this study's empirical investigation.For the purpose of analyzing the likelihood of a modal option, the research uses aggregate Logit modeling.Data is gathered for modeling purposes using a combination of primary and secondary surveys.Based on the research's conclusions, this article presents strategic solutions in four areas: redesigning road space, enhancing public transportation, utilizing mass rapid transit network (MRTS), and parking arrangements.
On a multi lane rural and urban highway, [35] used a range of dynamic merging management systems, including signalization for lane control (ultimately integrated with varying speed restrictions), to study the behavior of drivers who were open to platoon merging immediately from on ramps.Using within-subject repeated measures analysis and univariate statistics, sixty six motorists from the Province of Qatar were observed driving in a vehicle simulation.Based on the findings and the faster traffic rates on rural expressways, dynamic merging control appears to be more efficient.A static merging control with a cheap cost solution can take the place of control over dynamic merge, which on urban expressways did not result in any significant safety gains.
A study by [36] performed research to assess the level of traffic congestion in Pabna.In order to conduct the study, a traffic volume survey and a spot speed examination were the main methodological tools employed.The data that were collected were examined using a variety of statistical software programs.A number of traffic flow theories and models have also been used to calculate traffic flow parameters that reveal traffic characteristics.The research looked at the most common forms of transportation, including motorcycles, bicycles, auto rickshaws, and cycle rickshaws.It also looked at how congested the traffic is in the morning, noon, and evening.The investigation has also determined the main issues related to the various road segments' poor service levels.
The vulnerability of the Rural Traffic Network (RTN) in Zhangwu China was examined by [37] utilizing three traffic network models: the road level weight transport network system, the length weighted traffic network design, and the zero-power traffic network model.RTN was first constructed using the road mapping technique and the topological characteristics of complex network theory.Second, utilizing the Deliberate Attack and Random Attack tactics, the susceptibility of three models for rural transportation networks was investigated.The road level weight traffic network performs very well in illustrating RTN vulnerability by evaluating RTN attack tolerance under the circumstances of diverse attack patterns.
In a study by [38] at the Huludao Toll Station in Liaoning Province, China, the multilane separate highway has been thoroughly evaluated using simulation.By doing a comparative examination of various guiding strategies using the VISSIM software.The outcomes of the numerical simulation demonstrate that the guidance technique considerably increases efficiency and safety while lowering emissions and fuel use.
According to [39], decision-makers must quantify traffic congestion to implement mitigation measures that will increase the sustainability of the transportation system as a whole.By applying them to a daily and weekly traffic history dataset, the currently available traffic congestion measures were described and contrasted.The findings revealed that while each measure indicated a similar trend in congestion, they each exhibited substantial differences in congestion situations.The data analysis revealed the advantages and disadvantages of each measure.
A system for determining the necessary area for allocating centers of mass attraction was described by [40].The effectiveness of the nearby street and road network traffic management is the study's focus.They looked at the variables influencing the size of the land plot needed to allocate centers of mass attraction in the design of urbanized regions.They suggested a mathematical formula to determine the size of the land parcel needed for the allocation of a permanent facility while considering the typical transportation options offered for guests arriving by both private vehicle and public transportation to major attractions.
A study by [41] carried out research on approaches for the transportation system using crowd intelligence.This poll has identified a few issues with the intelligent transportation system and has suggested crowd-intelligent solutions.It is recommended that the design of the transportation system be divided into layers, with different solutions using crowd intelligence in each tier for those issues.Based on crowd intelligence, this study has covered solutions for parking, traffic prediction, traffic control, and mobility.Furthermore, the value of crowd-intelligent techniques and their applicability to the sustainable growth of future transportation infrastructure are stressed.
The adjustments made to an intersection model utilizing the PPTV VISSIM program and their effects on lowering GHG emissions and fuel usage were presented by [42] to prepare for the simulation of the intersection, one of Namangan, Uzbekistan's most troublesome crossroads was chosen, and its peak-hour traffic flow was investigated.In order to reduce the number of hazardous gases and fuel usage, the article presents two different sorts of solutions.In the first approach, the problem was made better by modifying the cycle duration and traffic signal phase.The second option involved altering the intersection's geometrical parameters to lessen the quantity of harmful gases and fuel used by automobiles.The present status of LOS was upgraded from a D level to an A level after the adoption of both solutions.
The City of San Jose's urban downtown network is being modelled utilizing microscopic vehicles movements simulation was described in detail by [43].The efficiency of adjustments to street design was then assessed using the model under various demand scenarios.This example of a street design alteration entails converting a one-way roadway to a two-way street.Additionally, under various trip demand decrease assumptions (10%, 20%, and 30%), the basic situations network was investigated to locate the city network corridors where tactical urbanism methods (such open-air eating) may be most successfully implemented.To analyze and successfully execute entire streets/tactical urbanism methods, the research offers a methodology for incorporating a microscopic model into a system for supporting decisions.
According to [44], a smart traffic signal controller and smart transportation system were designed.Based on the requirements of future smart cities for justice, decreasing commuting times, providing appropriate traffic flow, minimizing traffic congestion, and giving precedence to emergency vehicles, and offered local traffic management of a junction.The suggested system works better than the conventional management system, according to simulation data, and maybe a contender for the system for managing traffic in the upcoming smart urban areas.The suggested adaptive method improves the number of cars being serviced while simultaneously reducing the average waiting time (delay) by a substantial amount.Additionally, the STS hardware prototype was demonstrated.
A case study on qualitative analysis of the governing traffic management policy agreements in Seattle's Downtown and South Lake Union area was provided by [45].One of the most significant conclusions is that developers favor non-traditional TDM strategies like parking management and frontage enhancement.When compared to bike and walking programs, high-occupancy vehicle (HOV) elements had greater acceptance rates (59 and 63 percent, respectively).Future TDM regulations might benefit, it is decided, if a study into the efficiency of a variety of management alternatives resulting from real estate trends toward green buildings, tenants' beliefs in sustainability, and local policies to cut down on car journeys is conducted.
In order to model three different aspects of traffic data, a prediction model of traffic flow that uses three cycle dependent components was developed [46].The long and short-term memory network (LSTM) and attention mechanism were combined with the convolutional neural network (CNN) to extract spatial information, and to dynamically capture the effect of historical era on target period.Finally, each component's weighted integration was used to get the findings.Its forecast outcome was more accurate, and it may be used as a guide for managing the urban transportation sector against a backdrop of big data.
In Surat, a city in western India, a multi-legged junction called Kamrej crossroads was the subject of a case study by [47] using traffic data including traffic volume counts and spot speeds, PTV-VISSIM software was used to construct and calibrate the present field condition (base model).After calibration, the model's accuracy was checked using peak-hour traffic flow and the average travel time for each traffic movement by vehicle class.To evaluate the efficacy of several proposed traffic management methods, average delay was employed as a metric.It was shown that waits for moves that are straight and right may be significantly decreased when various demand management scenarios are evaluated, improving efficiency and traffic operations at certain crossings.
A study by [48] assessed how road diets affected safety, congestion, and cut-through on two comparable routes in Northeast Los Angeles by using collision data, traffic count data, and Bluetooth travel data.The findings indicated that there was some evidence that the road diet enhanced traffic safety outcomes, but there was no proof that it led to unacceptably heavy traffic or increased neighborhood cut-through traffic.
Road diet design was used in a new way in an urban corridor, according to [49].A four-lane, twoway road will particularly be reduced to two lanes, two direction road, with 24-hour parking spaces for both directions, under the current proposal.In the northwest of Washington, on New Jersey Avenue, the study looked at how implementing a road diet affected traffic.Along the route, there were five signalized and one unsignalized intersection.Site-Specific Empirical Bayes analysis and before-andafter investigations using Synchro 11 simulation were utilized to assess and contrast the current and suggested situations.The outcome found that unsignalized crossings performed better when a road diet design was used because of the traffic's diversion from their subsidiary roads and increased the safety of the research region by reducing the anticipated yearly number of collisions.The paper recommends that signal timings be revised to increase operational advantages and align with traffic needs when a road diet design is adopted.

Conclusions
This research is seeking to determine the most effective method to reduce traffic congestion in a specific traffic network.The output of this study is that there are two ways of controlling congestions: the first is through supply-side using variety of tools that enable transportation to make up the supply of transportation, they could be divided into three categories: infrastructure (such as roads built for circulation), means of transportation (such as cars), and management of both and controlling with demand-side action.The second is controlling congestion with demand-side actions through regulating both on-and off-street parking, spreading out or staggered work, schools, and businesses schedules, restricting or forbidding the use of specific vehicles during hours, utilizing both automated and manual collecting methods for road pricing, techniques and scenarios that reduce traffic by enforcing, and minimizing the need to travel and following one's own convictions.The study also discovered that using traffic simulation software packages are essential to simulate current conditions and to examine different future scenarios and their impact on the selected street network and on city.