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Submitted to the Vietnam MOT Conference: 2015

A Vision for Intelligent Transportation Systems and Traffic Safety in the Era of Big Data

Satish Ukkusuri, Professor of Civil Engineering, Purdue UniversityWenbo Zhang, PhD Candidate, Purdue University

ABSTRACT

With rapid economic growth in developing countries, vehicle ownership and trip making has increased resulting in more congestion and safety issues. The transportation infrastructure and management, however, lag behind relatively. This leads to deteriorated quality of life (congestion and emissions) and traffic crashes. More importantly, the growing inequalities between access to transportation and the interactions between motorized vehicles and non-motorized transportation modes on roads. This is compounded by the heterogeneity of vehicle class (e.g. motorbikes, three wheelers etc) in developing countries. Due to the lack of enough traffic barricades and smart traffic controls, the mixed traffic increases the traffic crash frequency and results in increased risk for non-motorized transportation modes.

This paper will introduce new ideas and strategies, such as vision zero program, for reducing the overall crashes in a country. Then the paper reviews the new trends in speed limit, especially variable speed limit, physical isolations. Furthermore, some special policies, developed for non-motorized transportation modes, especially for motorized/electrical bicycles, to reduce traffic crashes, are discussed. Second, to optimize the management of traffic at the network level and at intersections smart intersection control strategies will be presented. Data to support the traffic management from cameras, GPS equipped vehicles and social media will be discussed. A demonstration of the different tools developed by Dr. Ukkusuri’s lab will be shown. Finally, combining with the new trends in connected vehicles and autonomous vehicles, the potential benefits of these revolutionary transportation tools, especially in traffic safety, are summarized.

The document contains proprietary information

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INTRODUCTION

According to the report released by World Health Organization (WHO), road traffic injuries has become the eighth leading cause of death all over the world, especially for the youth between 15 and 29. (World Health Organization, 2013a) Each year, approximately 1.24 million people die on roads and another 20 to 50 million sustain non-fatal injuries. Although no overall reduction in the number of people died from traffic crashes, considering the context of 15% increase in the number of registered vehicles, most countries have made progresses in reducing the related deaths and also show that this reduction is possible. However, the report from the WHO also shows that the total number of road traffic deaths remains unacceptably high and can be reduced further, especially in low- and middle- income countries, such as Vietnam. Figure 1 shows changes in the road traffic deaths rate in Vietnam and 10 other countries, including a few developed countries and some countries in Southeast Asia. From the figure, the road traffic death per 100,000 populations has a decreasing trend in Vietnam in recent years. The average level, however, is still significantly higher than most countries that have an average level of less than 10 deaths per 100,000 populations. Thus, the reduction in road traffic deaths is still possible in Vietnam and more efforts should be made for this field.

Figure 1. The changes in road traffic deaths rate in Vietnam and 10 other countries

The report from WHO also discussed the traffic laws or policies that address five main risk factors, including speed, drunk-driving, helmets, seat-belts, and child restraints. Only 28 countries that cover 7% of the world’s population have


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adequate laws or policies. (World Health Organization, 2013b) For most countries with corresponding laws or policies, the enforcement that is critical to success is inadequate. In addition, over a third of road traffic deaths in low- and middle- income countries are related to pedestrians and cyclists. However, less than 35% of those countries have policies in place to protect these road users. For example, Vietnam is with national speed limit, drink-driving law, motorcycle helmet law, seat-belt law, and mobile phones prohibition while driving. Especially for motorcycle helmet law, this has pushed the helmet-wearing rate from below 30% to over 95%. This big progress didn’t change the safety of vulnerable groups significantly, as shown in Figure 2-a. And less effective enforcement should still be improved, as shown in Figure 2-b. there is also a pressing need to introduce new techniques or ideas to solve current road-crash crisis in the country.

(a) road traffic crash distribution among vehicle types

(b) causes of road traffic crashesFigure 2 Road traffic crash analysis in Vietnam

Different from traditional 5E’s (i.e. Engineering, Education, Enforcement, Emergency, and Evaluation) approach to safety, more and more transportation


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system designers are trying to explore solutions through technological improvements, such as Intelligent Transportation System (ITS). It has been verified that related ITS technologies can improve transportation safety and mobility, reduce environmental impacts, and enhance productivity through incorporating advanced information and communication techniques into transportation system. The United States Department of Transportation has long been a leader and strong supporter of ITS and also issues a strategic plan in the next five years, i.e. realizing connected vehicle implementation and advancing automation. (Barbaresso et al, 2014) Furthermore, according to the Grand View Research Inc., an institution on market research and consulting, the global market for ITS is expected to reach USD 38.68 billion by 2020. ITS aids in reducing incidents such as road accidents and boost safety, which is estimated to positively impact demand over the next six years.

This paper tries to integrate the ITS and road traffic safety. Besides some new ideas in traffic safety in the second part, the paper will introduce some advanced approaches to a safer highway and intersection in the third and fourth part respectively. Moreover, some new and automated data collection techniques under this era of big data are introduced to assist in developing smart and safer highways. Finally, future directions in ITS, such as connected vehicles and autonomous vehicles, are discussed to approach road traffic safety.

VISION ZERO PROGRAM

Vision zero is a bill on traffic safety, passed by the Swedish Parliament in 997. It states that vision zero means that eventually no one will be killed or seriously injured within the road transport system and that the transport system designers – including members of the motor vehicle industry, road traffic planners, road safety engineers, police, health professionals, educators, and road users- have a shared responsibility to ensure that the transportation system protects all travelers, even when they make mistakes or are at fault. (Fahlquist, 2006; Tingvall, 1997) This idea is also called “Scandinavian model” of road safety thinking. The new paradigm is significantly different from traditional traffic safety philosophy (McAndrews, 2013; World Health Organization, 2004):

1. Traffic injuries are preventable, not accidental;2. In addition to road user, all stakeholders- transportation, health, and so on-

are responsible for road safety and should share responsibility for it;3. Transportation systems should be designed to be tolerant of road users’

errors, and road users who make errors should not die or be seriously injured because of them;

4. Safe transportation systems should be designed around the human body’s limited tolerance for harmful kinetic energy;

5. Road safety is a social equity issue, not just an engineering and design problem;


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6. Assistance from high-income to low-income countries should target local conditions and needs; and

7. Safety interventions should be based on local knowledge, not only the application of professional guidelines.

The distribution of responsibility introduced by Vision Zero could be an efficient tool to use to get closer to achieving the goal of substantially reducing road traffic deaths. However, this paradigm does suggest a code of ethics for road safety experts and not include ways in which experts can be held directly accountable for traffic crashes in a consistent or coherent way. In order to implement this ambitious and far-reaching goal and have long-lasting effects, it is very important and necessary that the industry does its part and the crucial question is how this can be achieved and whether legal sanctions have to be attached to the current distribution of moral responsibility for it to be truly efficient.

Based on the current most cost-effective measures, some studies also tried to propose measures under Vision Zero in five main areas, including speed regulation, application of ITS, vehicle modification, road system modification, new safety regulations for road users, and strict enforcement. (Elvik, 1999) Although these measures haven’t met the underlying idea of Vision Zero to stimulate the development of new safety measures, it is a good initial step to implement Vision Zero. Some US major cities, such as New York City (NYC), San Francisco, and Boston, have started to implement Vision Zero. Taking NYC as example, the city council passed 11 bills and 6 resolutions to implement Vision Zero Action Plan across many city departments in 2013, including: strict enforcement for speeding, failure to yield to pedestrians, and dangerous driving; a campaign in the state legislature to allow the city to lower speed limits to 25mph; safety improvements such as traffic calming, speed cameras, and slow zones on streets; stricter scrutiny of taxi drivers’ safety records; and street safety curriculum in schools. (Walljasper, 2015) Till 2014, the maximum speed limit of almost 90% of streets in NYC has been reduced from 30mph to 25mph. Meanwhile, the speeding tickets increased by 40%. Figure 3 shows the system with statistics of fatalities and injuries in August 2015, as a part of NYC vision zero action plan. The results are also promising that the NYC had an historic low for pedestrian fatalities in 2014.

Different from the Vision Zero to reduce road traffic deaths and serious injuries, some new concepts of motorcyclist safety polices go further and is more focused on accident prevention than death and injury reduction. With better understanding of motorcycles and motorcyclists, the riders’ organization in western countries also proposed their safety improvements within five aspects, i.e. human/motorcyclists, vehicle/motorcycles, transportation environment and infrastructure, and social impacts. The detail policy mainly includes licensing, training crash avoidance skills, education on hazard awareness and panic management, personal protective equipment, motorcycle modification and


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intelligent equipment, road hazards and maintenance, motorist awareness, rider peer pressure, and public attitude.

Figure 3 The system under NYC Vision Zero Action Plan

SAFER AND SMART HIGHWAYS

Variable speed limit

Speed limit is a widely used strategy to implement Vision Zero. Typically, depending on temporal dimension, the speed limit control strategy can be classified into two categories: traditional static speed limit and variable speed limit (VSL), as shown in Figure 4. Traditional static speed limit has been used for decades and shows fixed maximum speed through a traffic sign at a fixed segment. However, with the introduction of ITS, more and more engineers have been focusing on VSL that can change speed limit accordingly and dynamically. Because the speed limit is determined on the basis of prevailing road traffic and environmental conditions, VSL can directly and efficiently influence the road safety. Moreover, VSL is often based on the principle of speed homogenization over the road segment, which can further improve road capacity and reduce speed variability. Previous studies found that VSL reduces variance in speed, leads to fewer collisions, improve safety by about 50% and mobility by about 30%, and also reduces exhaust emissions by 2-8%. (Grumert and Tapani, 2012; Islam et al, 2013)


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(a) traditional static (b) variableFigure 4 The speed limit control strategy (sources: USDOT)

Except for the benefits of VSL, researchers also focused on how to implement VSL and develop optimal scheme. Islam et al (2013) collected data from an urban freeway corridor in Canada and tested the sensitivity of the VSL update frequency and the safety constraints for the VSL strategy based on micro simulation platform, VISSIM. To approach the best scenario in terms of safety and mobility, the VSL update frequency of 5 min and a maximum speed difference of 10 km/h between successive time steps yields the best performances. Zhu and Ukkusuri (2014) also proposed a novel method to determine optimal real time speed limit, which can account for uncertain traffic demand and supply in a stochastic traffic network. This study, different from traditional safety research, was based on stochastic network perspective and assigned time dependent speed limit for each link in this network. With the simulation on the Sioux Falls network, the VSL could reduce travel time and emissions by 18% and 20% respectively. Grumert and Tapani (2012) also discussed the cooperative VSL system that covered multi segments. In this cooperative VSL system, vehicles could communicate with roadside unit and receive updated speed limits before reaching a point where they can actually read the speed limit signs. The speed limits is given to the vehicles at predefined points in time and are depending on the vehicle speed, speed limits given from the roadside unit located in front of the vehicles, and distance between the vehicles and roadside unit. Thus, vehicles adapted their speed earlier and continuously, which could reduce the very high acceleration and deceleration rates and then improve safety, mobility, and emission.

Moveable or Active Physical Isolation

Traffic calming is the combination of mainly physical measures that reduce the negative effects of motor vehicle use, alter driver behaviors, and improve conditions for non-motorized street users. (Lockwood, 1997) This has been verified as one efficient way to protect non-motorized road traffics, such as pedestrian, motorcyclists, bicyclists, and transit users. The physical isolation, such


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as known as traffic barriers, guardrails, crash barriers, and traffic marking, is one of widely used traffic calming techniques. It can keep vehicles within their roadway and prevent vehicles from colliding with dangerous obstacles, opposing traffic, and vulnerable travelers, as shown in Figure 5-a. Moreover, it can also be used to protect vulnerable areas, such as school area and pedestrian zones from errant vehicles, as shown in Figure 5-b. The drawbacks of traffic barriers are also obvious, one of which is not moveable and cannot adapt traffic flow. An innovative moveable barrier technology has been invented to create safe and dynamic highways that offer real time roadway reconfiguration while maintaining positive barrier protection between lanes. The system uses a wall of interlocked 1-meter barriers that can be lifted and repositioned by transfer machine to create isolated zones or lanes for special purposes. The transfer machine can move with a speed of 11km/h. This system has been implemented on UK highway A21.

(a) median barriers (b) crash barriers for vulnerable travelersFigure 5 Traffic barriers on urban streets

Figure 6 Moveable barrier (Sources: Lindsay Inc.)

The above physical isolation techniques are efficient during daytime. The visibility of these techniques, however, will be a problem in nights. Furthermore, this problem is more serious in Vietnam. The roads are poorly lit and are with few road signs. Buses and trucks often travel at high speed with bright lights; and some motor vehicles don’t use any lights and may stop in road segments without illumination. The additional light and traffic signs on road are needed in Vietnam.


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The LED active light-emitting road traffic signs and barriers may be a potential solution. These signs and barriers can absorb and store solar energy through panel and battery and emit light actively in the dark, as shown in Figure 5 and 7. Besides these active light-emitting road traffic signs and barriers, some more smart traffic signs, markings, and barriers has been proposed, including glowing lines, interactive light, and Van Gogh bicycle path. All the three new things absorb solar energy during the day and emit lights in the dark. The glowing lines are mainly designed to show borders of each lane, as shown in Figure 8-a&b; the interactive light system is installed on median barriers and only turns on when traffic approaches in the dark, as shown in Figure 8-c; and the Van Gogh bicycle path is developed for bicyclists and makes up of thousands of sparkling stones that can be charged and emit light, as shown in Figure 8-d. These new innovations are seen as safe, sustainable, and cost-saving alternative to conventional lighting for dark roads.

Figure 7 LED active light-emitting road traffic signs

SAFER AND SMART INTERSECTIONS

Different from the physical isolation that separates traffic spatially on highway segments, traffic signals that separate traffics temporally are widely used at intersections. The traffic signals can reduce the traffic conflict greatly, which can improve traffic safety at intersections. There are three main types of traffic signal control strategies in practice, including the basic operation, the time-of-day operation, and the adaptive operation. The signal timing schemes for the first two types are programmed based on anticipated demand or anticipated demand at different time periods. The last one, however, requires vehicle detection and dynamically adjusts signal timing schemes based on current or historical demand, as shown in Figure 9-a. With the proliferation of communication and information techniques, Dresner and Stone (2008) proposed a multiagent systems approach to intersection management called autonomous intersection management that can utilize the full capacity of autonomous driving systems. This system describes a First Come, First Served policy for directing vehicles through an intersection. Moreover, all vehicles and infrastructures are connected and can communicate with each other; and no traditional traffic signals are installed at intersections, as shown in Figure 9-b. In simulation, this approach has been shown to yield


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significant improvements in intersection performance over conventional intersection control strategies, such as traffic signals and stop signs.

(a) Glowing lines on roads (b) Glowing lines from driver’s view

(c) Interactive light system (d) Van Gogh bicycle pathFigure 8 Innovations on smart highways

(Sources: Studio Roosegaarde & Heijmans)

(a) adaptive intersection (b) autonomous intersection Figure 9 Smart intersections (Sources: SCOOT, USDOT)

The Split Cycle Offset Optimization Technique (SCOOT) is a tool to implement adaptive system that responds automatically to fluctuations in traffic flow through the use of on-street detectors embedded in the urban roads. It has proven to be a world leader in urban traffic control that typically reduces traffic delay by an average of 20%. Furthermore, it also contains functions of bus priority, traffic gating, incident detection, on-line saturation occupancy measurement, and vehicle emission estimates. This tool has been installed successfully in several cities, such as Beijing, London, Toronto, Southampton, and York. Dr. Ukkusuri also explored


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different types of traffic control strategies extensively. Ukkusuri et al (2010) proposed a method to develop optimal and robust signal timing scheme considering network wide impacts, traffic dynamics, and uncertainty in the OD demand. Except for traffic signal control for a single intersection, Zhu et al (2015) proposed a machine learning method to inference exactly the best joint actions for all the coordinated intersections. Abdul Aziz et al (2012) made a further discussion on adaptive signal control and developed a new method to account for neighborhood congestion information sharing. Thus, in new methods, local traffic information, as well as neighborhood traffic information, are considered. Zhu and Ukkusuri (2015) also discussed the novel methods for autonomous intersection management accounting for traffic dynamics and connected vehicle environment in the context of system optimum network model. Another study by Abdul Azizi and Ukkusuri (2014) focused on individuals in terms of stopped delay at signalized intersections for the entire trip of a user and proposed a new control strategy that can yield benefits from connected vehicle environment and user perspectives.

DATA SUPPORT

ITS varies in techniques applied, from introduced techniques such as VSL to more advanced applications such as connected vehicles and autonomous vehicles. Additionally, predictive techniques are being developed to allow advanced modeling and comparison with historical baseline data. Smart decisions are made and distributed based on modeling, data, and communication techniques. Among these components, the data collection is an initial but also important step to approach ITS. For example, VSL needs input of link traffic state; and adaptive intersection needs input of queue length and neighborhood congestion information. Various data needs can also be met by various data collection techniques, such as floating vehicle data, sensing techniques, inductive loop detector, video vehicle detection, Bluetooth detection, and online tools.

Floating vehicle data collection, also called probe vehicle data collection, is a set of methods for obtaining travel time and speed data for vehicles traveling along roads. With the proliferation of location techniques, GPS and smartphones are equipped within vehicles and provide vehicle position information, as shown in Figure 10-a. Those readings from vehicles are used to estimate traffic states. Zhan et al (2013) used large-scale taxi GPS data in New York City to estimate urban link travel time. Known as non-intrusive method of traffic detection, video vehicle detection needs cameras, typically mounted on poles or structures above or adjacent to the lanes, and processors that analyze the changing characteristics of the video image as vehicle pass. The typical output of video detection system is speed, volume, occupancy, gaps, and headway, as well as stopped vehicle detection and wrong way vehicle alarms. Zhan et al (2015) estimated the real-time queue length based on license plate recognition data from video vehicle detection, as shown in Figure 10-b. Inductive loops, Bluetooth, and sensing detections,


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shown in Figure 10-c, d and e, are also accurate and inexpensive way to measure traffic state. Inductive loops are placed in a roadbed to detect vehicles as they pass through the loop’s magnetic field. Bluetooth is a wireless standard used to communicate between electronic devices. Bluetooth road sensors, installed at roadside, can detect Bluetooth MAC address from Bluetooth devices in passing vehicles. Interconnecting those Bluetooth road sensors can estimate link traffic states. Similar as Bluetooth, Radio Frequency Identification is one of sensing techniques and can identify passing vehicles through communication signals and receiving sensors. Sometimes, online resources are also available for traffic management, such as Google maps and traffic. In the project of “An agent based model for the adaptive traffic signal systems”, Dr. Ukkusuri collected traffic data from Google Maps and estimate link traffic state, as shown in Figure 10-f.

(a) Taxi GPS data in New York City (b) Video Camera in Beijing

(c) Inductive loop detector (d) Bluetooth detection


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(e) Sensing technique of RFID (f) Online tool of traffic stateFigure 10 Data collection techniques

(Sources: Dr. Ukkusuri’s group, USDOT, and Libelium Inc.)

FUTURE DIRECTIONS

ITS is a set of tools that facilitates a connected, integrated, and automated transportation system that is information-intensive to better serve the interests of users and be responsive to the needs of travelers and system operators. It integrates advanced communications-based information and electronic technologies into the transportation infrastructure and vehicles. The USDOT, as a national and even worldwide leader in ITS program, has issued the priorities that guide the development to harness the personal involvement in near future. (Barbaresso, 2014) These priorities reflect the needs of stakeholders, including not only research but also the deployment and implementation of specific technologies. The first priority of realizing connected vehicle implementation builds on substantial progress in recent years around design, testing, and planning for connected vehicles to be deployed across the nations. The second priority of advancing automation allows the ITS program to delve into this innovative and cutting-edge field to research, develop, and adopt automation-related techniques as they emerge.

Different connected vehicle test beds that can offer supporting vehicles, infrastructure, and equipment to serve the needs of public- and private- sector testing and certification activities in real world have been created and operating for several years in four different states, i.e. Michigan, Virginia, California, and Florida. From the test results, the connected vehicle system have proven to potentially reduce 81% of all-vehicle target crashes, 83% of all light-vehicle target crashes, and 72% of all heavy-truck target crashes annually. (RITA, 2014) The industry also developed different prototypes of autonomous vehicles, such as Google Self-Driving Car, as shown in Figure 11. The prototypes have been allowed to take public road testing in California, Michigan, Florida, Nevada, and Texas. As of July 2015, all 23 Google Self-Driving Car involved in 14 minor traffic accidents with a total vehicle travelled miles of more than 2 million miles.


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Furthermore, in all cases the vehicle itself was not at fault. The Google has planned to release the self-driving car model for general public from 2017 to 2020.

Figure 11 The prototype of Google Self-Driving Car (Sources: Google)

SUMMARY

In this new century, the philosophy of traffic safety improvements has changed to a shared responsibility. All stakeholders are involved in this campaign to reduce road traffic deaths and injuries. Besides the ideas, the tools and techniques that are used for traffic safety with the proliferation of communication techniques, information techniques, and intelligent transportation system. This study also introduced some new trends in the convergence of intelligent transportation system and traffic safety. At this great changing world, as well as transportation system, this is also a valued opportunity for developing countries, such as Vietnam, to improve current transportation system and reduce relatively higher traffic crash rates.

REFERENCE

Abdul Aziz, H.M., Ukkusuri, S.V. (2014) Network traffic control in Cyber-Transportation systems accounting for user level fairness. Journal of Intelligent Transportation Systems: technology, planning, and operations.

Abdul Aziz, H.M., Zhu, F., Ukkusuri, S.V. (2012) Reinforcement learning based signal control using R-Markov average reward technique accounting for neighborhood congestion information sharing. The 92nd Annual Meeting of Transportation Research Board.

Barbaresso, J., Cordahi, G., Garcia, D., Hill, C., Jendzejec, A., and Wright K. (2014) USDOT’s intelligent transportation systems ITS strategic plan 2015-2019. FHWA-JPO-14-145. Washington DC.

Dresner, K., Stone, P. (2008) A multiagent approach to autonomous intersection management. Journal of Artificial Intelligence Research.


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Elvik, R. (1999) Can injury prevention efforts go too far? Reflections on some possible implications of Vision Zero for road accident fatalities. Accident Analysis and Prevention, 31:265-286

Fahlquist, J.N. (2006) Responsibility ascriptions and vision zero. Accident Analysis and Prevention, 38: 1113-1118.

Grumert, E., Tapani, A. (2012) Impacts of a cooperative variable speed limit system. Procedia-social and behavioral sciences, 43:595-606.

Islam, M.T., Hadiuzzaman, M., Fang, J., Qiu, T.Z., El-Basyouny, K. (2013) Assessing mobility and safety impacts of a variable speed limit control strategy. Transportation Research Record, 2364:1-11.

Lockwood, I. (1997) ITE traffic calming definition. ITE Journal, 22.McAndrews, C. (2013) Road safety as a shared responsibility and a public

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RITA. (2014) Connected vehicle research in the United States. http://www.its. dot.gov/connected_vehicle/connected_vehicle_research.htm. Accessed on October 12, 2015

Tingvall, C. (1997) The zero vision: a road transport system free from serious health losses. Transportation, Traffic Safety, and Health: the New Mobility, edited by Hans von Holst, Ake Nygren, and Roland Thord, 37-57, Goteborg, Sweden: Springer.

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Walljasper, J. (2015) The safest streets: vision zero aims to eliminate all traffic fatalities. American Planning Association, May 2015.

World Health Organization. (2004) World report on road traffic injury prevention, edited by Margie Peden et al. Geneva, Switzerland: World Health Organization and the World Bank Group.

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