Roadway Users Research Articles

Violations Modeling in Studies of Concurrent-Flow Lanes

State agencies have become increasingly interested in the construction of managed-lane facilities operating concurrently with general purpose lanes along existing roadways as a means of addressing the continued growth of traffic congestion on freeways. Nonbarrier separation techniques to restrict access to managed lanes are gaining in popularity. Such separation methods, however, permit nearly unlimited improper ingress to and egress from the managed lanes, affecting free-flow speeds, safety, and revenues. Even with significant enforcement, violation rates related to non-barrier-separated managed lanes in the United States are considerable. Despite this, such violation behavior has not been incorporated into any model developed to predict improvements in traffic performance metrics and the potential revenue that can be raised through the introduction of a new high-occupancy toll (HOT) lane facility within an existing roadway or to assess potential practicable operational strategies and facility designs. Nor has any prior study systematically considered the impact of violation on the performance of these facilities. This paper seeks to assess the importance of this omission. Results of this study indicate that vehicles whose drivers choose to violate restrictions on the studied non-barrier-separated, limited-access HOT lane facility significantly affect roadway facility performance estimates when violation rates reach 10% of roadway users or higher.

The contribution of traumatic brain injury to the medical and economic outcomes of motor vehicle-related injuries in Ohio

Objective To describe traumatic brain injury (TBI) among injured roadway users. Aim 1 assessed the association of age, gender, alcohol/drug use, safety equipment use, type of roadway user, metropolitan area, and primary payer with motor vehicle-related TBI outcome. Aim 2 assessed the relationship of motor vehicle-related TBI and risk/protective factors with medical and economic outcomes. Methods Population-level hospital and trauma databases from the Ohio Hospital Association and Ohio Department of Public Safety, respectively, were probabilistically linked for 2003 through 2006. Injured roadway users (motor vehicle occupants, motorcyclists, bicyclists, pedestrians, and others) were assessed for TBI, ventilator use, intensive care unit (ICU) admission, injury severity score (ISS), need for rehabilitation, death, and total hospital charges. Results The odds of a motor vehicle-related TBI were greater among those not using safety equipment (OR = 1.56). The interactions of alcohol/drug use by gender and of alcohol/drug use by location were significant. Sustaining a TBI increased the odds of requiring ventilation (OR = 3.66), being admitted to the ICU (OR = 2.51), having a high ISS (OR = 4.24), requiring rehabilitation (OR = 2.22), or death (OR = 2.52). When compared with a non-TBI, total hospital charges increased by a factor of 1.35 for a TBI. Hospital charges were $46,441 on average for individuals who sustained a TBI, whereas mean hospital charges were $32,614 for patients with a non-TBI. Conclusions Among injured roadway users, individuals who sustain a TBI are more likely to require extensive medical care and have injuries resulting in death. Impact on industry Prevention strategies aimed at reducing alcohol use and increasing safety device use should be encouraged to reduce the burden of TBI.

Estimating User Costs and Economic Impacts of Roadway Construction in Six Federal Lands Projects

The Federal Lands Highway (FLH) Division staff faces myriad challenges when designing roadway construction projects for roads located on federal lands. An increasingly prevalent challenge is considering not only the “hard” costs of a construction project (e.g., labor and materials) but also the “soft” costs of user delay and the economic impacts on roadway users (e.g., residents, visitors, staff, and local businesses). These soft costs affect every roadway construction project but rarely are considered in design and operation because they often are difficult to estimate and justify. FHWA's 1998 report Meeting the Customer's Needs for Mobility and Safety During Construction and Maintenance Operations identifies this issue and recommends that engineers begin to address it, for small- as well as large-scale projects. As part of its responsibility to promote the development and deployment of applied research, FLH staff initiated the development of FLH-QuickZone to help estimate these soft costs of roadway construction. As part of its development, FLH-QuickZone was tested and prototyped in six FLH construction projects: three in national parks, two on forest highways, and one in a national recreation area. Where FLH-QuickZone fits in a spectrum of other estimation tools for work zone delay and how it was used in the six FLH roadway construction projects are summarized. Observations about the challenge of addressing the soft cost of roadway construction projects–with FLH-QuickZone or other analytical tools–also are presented.

SPUTERS: An Integrated Traffic Surveillance and Emergency Response Architecture

Secure Progressively Updatable Traffic Emergency Response System (SPUTERS) is a framework for collecting traffic-surveillance data in crash-prone areas of roadways. SPUTERS receives as input video, audio, and text-based data from an integrated collection of distributed cameras and sensors, both vehicle-borne and those embedded in the roadway infrastructure. Under nominal roadway operating conditions, the multimedia data are used to develop incident countermeasures. During degraded modes of roadway operation, SPUTERS generates progressive updates to create a shared situational awareness among the people who orchestrate responses to traffic incidents and emergencies. In addition to addressing performance-oriented quality-of-service requirements for interactive display of data on handheld devices, SPUTERS relies on role-based access control to safeguard the privacy of roadway users under surveillance, preventing privileged information collected and managed by the system from being leaked to unauthorized persons. In order to enhance security, SPUTERS uses symmetric key encryption to guard against the unauthorized alteration of the surveillance data.

Effects of Variation in Quarter-Car Simulation Speed on International Roughness Index Algorithm

The international roughness index (IRI) is widely used throughout the world as a measure of road roughness. A quarter-car simulation at 80 km/h is performed on the longitudinal profile to compute IRI. Questions have been raised regarding the applicability of IRI for roads that are used at speeds above or below this simulation speed. To gain more insight into the effects of simulation speed, an investigation was carried out to determine how the roughness computed from the IRI model changes for different simulation speeds of the quarter car. This investigation was performed on an asphalt concrete data set and a jointed portland cement concrete data set. For simulation speeds between 60 and 110 km/h, the response from the IRI model was within ±0.20 m/km of the IRI for 80% of the asphalt sections and 61 % of the concrete sections used in the study. Although the output from the quarter-car model for the different simulation speeds was different from the IRI (simulation speed of 80 km/h), it is unclear to what extent a user's perception of the roughness of a roadway changes with the speed of travel. If examples of roadways are found where the subjective opinion of roadway users of the roughness seems inconsistent with the IRI, it is recommended that the IRI model be used with the current speed limit of the roadway to examine whether the obtained output provides a better match with the opinion expressed by roadway users.

A revised economic analysis of restrictions on the use of cell phones while driving.

Evidence that cell phone use while driving increases the risk of being involved in a motor vehicle crash has led policymakers to consider prohibitions on this practice. However, while restrictions would reduce property loss, injuries, and fatalities, consumers would lose the convenience of using these devices while driving. Quantifying the risks and benefits associated with cell phone use while driving is complicated by substantial uncertainty in the estimates of several important inputs, including the extent to which cell phone use increases a driver's risk of being involved in a crash, the amount of time drivers spend using cell phones (and hence their aggregate contribution to crashes, injuries, and fatalities), and the incremental value to users of being able to make calls while driving. Two prominent studies that have investigated cell phone use while driving have concluded that the practice should not be banned. One finds that the benefits of calls made while driving substantially exceed their costs while the other finds that other interventions could reduce motor vehicle injuries and fatalities (measured in terms of quality adjusted life years) at a lower cost. Another issue is that cell phone use imposes increased (involuntary) risks on other roadway users. This article revises the assumptions used in the two previous analyses to make them consistent and updates them using recent data. The result is a best estimate of zero for the net benefit of cell phone use while driving, a finding that differs substantially from the previous study. Our revised cost-effectiveness estimate for cell phone use while driving moves in the other direction, finding that the cost per quality adjusted life year increases modestly compared to the previous estimate. Both estimates are very uncertain.

Multimodal Level-of-Service Analysis at Planning Level

Methods of determining the level of service (LOS) to scheduled fixed-route bus users, pedestrians, and bicyclists on arterials and through vehicles are presented. The research is based on LOS research for the individual modes and uses a comprehensive arterial approach based on research conducted in Florida. The Florida Department of Transportation (FDOT) developed a multimodal LOS analysis process to measure and provide mobility for diverse roadway users. In 1999 the Florida legislature authorized creation of multimodal transportation districts. It also directed FDOT to develop methods for the measurement of performances of various transportation modes to assist local governments with concurrency requirements for growth management. The Highway Capacity Manual’s (HCM) assessment of arterial LOS does not describe the quality of transportation service provided by the facility as much as it describes the quality of service provided to the through vehicle (automobile) users on the facility. Although this concept does address the primary mode of travel, it does not address the service that the arterial provides to other major potential modes (e.g., transit, walking, bicycling) or allow a multimodal LOS analysis. In the 2000 HCM, LOSs for pedestrians and bicyclists are essentially based on how crowded the respective modal facilities are. However, recent research on quality of service for pedestrians and bicyclists indicates that the most important factors are the lateral separation of the mode and motorized vehicle volume, speed, and type and frequency of transit service. FDOT’s research has applied these models with planning-level assumptions.

Analyzing Influence of Geometric Design on Operating Speeds Along Low-Speed Urban Streets: Mixed-Model Approach

Studies have documented the significant effect of horizontal curvature on operating speed on two-lane rural highways. The geometric design of these facilities emphasizes the forgiving roadside to accommodate the higher vehicular speeds. High-speed geometric design is predicated on selecting design values for geometric elements that promote speed consistency and safety. The low-speed environment has different objectives in trying to provide access and accommodate multiple roadway users, such as bicyclists and pedestrians. The goal is to maintain lower speeds and thus to achieve the functionality of the roadway and improve overall safety. Too often, the speeds on these facilities exceed the intended target speed of the roadway. A study conducted by the Pennsylvania Transportation Institute supported several research efforts in the low-speed environment. Presented is a more sophisticated analysis of low-speed urban street data using mixed models. A mixed-model statistical approach with repeated measures is used to analyze the influence of geometric elements on operating speed. The power of a mixed-model approach is that it accounts for the random effect in the database (such as the data collection sites themselves) while modeling the fixed geometric effects. Because data were collected at several points along each roadway, the analysis also applies a repeated-measures approach that addresses the geometric elements effect on the same subjects traversing a roadway. The advantages and disadvantages of applying a more sophisticated statistical approach are presented.

Good Fences Make Good Neighbors: Highway Noise Barriers and the Built Environment

Noise barriers have become a prominent feature on today’s landscape. Unfortunately, they have also become a feature associated with insensitivity toward the built environment. Designers could avoid the negative visual impact that noise barriers frequently create by increasing their awareness of aesthetics in the design process. In an effort to improve the quality of noise barrier design, the New Jersey Department of Transportation’s, Bureau of Environmental Analysis (BEA) altered the design process for its I-76/I-295 Type II noise abatement study. The first objective of the study was to acoustically engineer a barrier that would abate the noise for residents along the affected roadway corridor. The second was to develop an architectural design that would be aesthetically pleasing to the corridor resident and the roadway users. Typically, architects were brought into the design process at the end to review the aesthetic impact of the wall and add architectural features. On the I-76/I-295 project, BEA initiated a parallel process with the architectural design running concurrent with the engineering. The architectural design process and the interfacing of this process with the engineering are described. Community involvement was essential to the architectural objective of designing an aesthetically pleasing barrier. Ideas reflecting community concerns and comments were refined into final recommendations for construction of a noise barrier with gateways and a unifying corridor theme. The noise barrier should then become a representation of the community and stand as an icon in the built environment. Noise barriers can have a positive impact on the built environment if a commitment is made to aesthetics throughout the design process.

Flexible pavement design and management. Systems approach implementation : Lytton, R L; McFarland, W F; Schafer, D L U S Transportation Research Board NCHRP_report 160, 1975, 53P

This report describes an operational computer program (SAMP6) that provides a basis for selecting flexible pavement design and management strategies with the lowest predicted total cost over a prescribed analysis period when considering such cost elements as initial construction, routine maintenance, periodic rehabilitation, interest on investment, salvage value, and roadway users cost. The program uses the AASHTO Interim Guides as its structural subsystem and the predicted decrease in serviceability with time and traffic as developed at the AASHO Road Test. The strategy selection capability is a quantitative procedure for considering long-term advantages and disadvantages of staged construction versus strong initial structural designs.

ANALISIS BIAYA DAN PENANGANAN LOKASI RAWAN KECELAKAAN AKIBAT KECELAKAAN LALU LINTAS DI KOTA DENPASAR

Denpasar city has a traffic accident rate is high compared to most other regions. Contributing factor is the traffic condition, which is an accumulation of traffic conditions the interaction of the various characteristics of driver, vehicle, road infrastructure and environmental characteristics. By that condition, it needs an effort to identify the black site, black spot, the cost of accidents and treatment efforts to reduce traffic accidents. The research has used secondary data from local police department as an accident data from 2007 until 2011 and survey’s data on the location. Of which data continue to be analyzed with the number of accident to find out the black site with Z-score method and to determine the black spot with cusum method. While the analysis of accident cost using the method of Gross Output (Human Capital). In restraining accident, a research should be done to identify causing accident factors. Based on analysis of black site obtained that the lines of the street in denpasar as an black site is on quadrant A, consisting of Ngurah Rai By pass line, Gatot Subroto and Imam Bonjol lines. The Cusum determination done to identify the location of black spot found on Ngurah Rai Bypass street Sta 8 - Sta 9 with cusum score 12,938.The cost of accident victims and accident costs were highest in 2011 in the amount of 36.988.633.141/year and 81.267.473.411/year. Recommendation from the research is that government should observe safety factors for the roadway users with put in traffic sign and the other safety facilities on research areas which has black spot.