bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Activity Chaining Model Incorporating a Time Use Problem to Network Demand Analysis
Authors: Kim Hyunmyung , Oh Jun-Seok , Jayakrishnan R.
Published: May 2018

An activity chaining model described as a time use problem is presented. Unlike existing activity chaining models, the time use problem includes all choice attributes related to time, not only when and where the activity is performed but also the duration of the activity. To apply the time use problem to transportation network demand analysis, the opportunity cost of travel time is modeled through a constraint approach, and the value of activity is represented by time-dependent utility profiles. In the model, among activity alternatives, the activity with the biggest utility is sequentially included within an individual's daily disposable income. Through the sequential selection process, not only the activity type but also its start time and duration are simultaneously determined on the basis of an individual's perceived time-dependent travel time for the activity. Since the activity chaining is performed on the basis of the dynamic travel times calculated via traffic network simulation, the activity chaining is iteratively updated through a day-to-day dynamic process. The model is applied to a medium-size network to show its applicability. The example sheds light on the practicality of activity-based models and extends applications of the travel demand model to market analysis by illustrating how the model can analyze impact of transportation network improvement on the activity pattern and zonal socioeconomic conditions particularly associated with shopping and leisure activities.
Meeting Appointment and Waiting Behavior with Mobile Communications
Authors: Ohmori Nobuaki , Hirano Takayuki , Harata Noboru
Published: May 2018

Information and communications technologies (ICT) have provided people with many activity opportunities for communications in cyberspace. Mobile phones have made decisions about activity scheduling more flexible and changed travel behavior dramatically. Meeting and waiting behavior could be among the most dramatically changed behaviors since the introduction of ICT. Mobile phones allow one to reschedule appointment time and place without space–time constraints. Young people especially use mobile communications frequently and cleverly. A study was done to investigate young people's decisions about meeting and waiting behaviors and to analyze dynamic rescheduling behavior by mobile communications, in spatial and temporal dimensions. An on-site interviewing survey was conducted in Shinjuku, Tokyo, in December 2003. Information on telecommunications relating to (re)scheduling meeting time and place and on waiting behavior was obtained from 87 young pairs. Reasons for telecommunicating by mobile phone were classified into five categories: making an appointment and deciding on meeting time and place, rescheduling the meeting time, rescheduling the meeting place, informing of late arrival, and informing of the arrival and confirming current location. About half of those who were first to arrive participated in activities that were not at the agreed-on meeting place but were at other activity opportunities near the meeting place. The first arrival's activity choice behavior while waiting was affected by the frequency of visits to the town, whether he or she was considering the possible opportunities around the meeting place, and the length of the expected waiting time and the additional expected waiting time.
Wireless Internet on Trains
Authors: Zhang Min , Marchau Vincent , Van Wee Bert , Van Der Hoorn Toon
Published: May 2018

Wireless Internet service (WIS) is finding increasing implementation in the Netherlands via several markets. Recently, the idea has emerged of providing WIS through public transport services. The impact of WIS on train travelers, particularly on business travelers, is, however, unknown. In a study to examine this impact, respondents were surveyed to find out how WIS might affect their travel and work performance. Respondents were also questioned about their willingness to pay for WIS and their preferred WIS characteristics. In general, respondents were positive about WIS and were willing to spend an average of €3.17 [Eur 1 = U.S. $1.28 (2006)] per trip for its use. Furthermore, they considered data security the most important WIS feature. Hence, it can be concluded that WIS deserves to be implemented in train services for business travelers as a means to enhance their travel and work performance during traveling.
Weather-Responsive Signal Timing
Authors: Al-Kaisy Ahmed , Freedman Zachary
Published: May 2018

This paper presents a systematic investigation into the effects of adverse weather on signal operation and the potential benefits of implementing weather-responsive signal control. The investigation considered isolated and coordinated signalized intersections in urban and suburban areas under various traffic conditions. Both operational and safety analyses were conducted in this investigation. Traffic signal optimization and microscopic traffic simulation were used to perform the operational analysis with average travel time as a performance measure. The safety analysis used the adequacy of change and clearance intervals and the presence of dilemma zones as indicators of safety at signalized intersections. Study results suggest that operational benefits of weather-responsive signal control are generally significant and that the greatest benefits can be realized at coordinated corridors in town and city centers. Results also suggest that dilemma zones are most likely introduced on a particular intersection approach once the coefficient of friction between tire and pavement drops below the design value of a wet pavement. Further, a set of recommended guidelines that relate weather conditions to operational impacts and potential benefits of weather-responsive signal timing was developed and provided in this study.
Saturation Flow at Signalized Intersections during Longer Green Time
Authors: Khosla Karan , Williams James C.
Published: May 2018

Traffic signal timing is one of the most important tasks traffic engineers face in the United States. Saturation flow is a key input for optimal signal timing. A small variation in saturation flow values could affect changes in cycle length and thereby affect the efficiency and operation of an urban street system. A great deal of research on estimating saturation values has been done, taking into account prevailing conditions at signalized intersections. Various methods exist for determining saturation flow by observing queues of vehicles at an intersection and determining their respective headways, but little research has been carried out to evaluate the effect of longer green periods on saturation flow. A few studies have suggested a decrease in saturation flow after 30 to 40 s of green. This paper examines the effects of longer greens on saturation flow at signalized intersection approaches in the Dallas–Fort Worth (DFW) metropolitan area of Texas. Five signalized intersection approaches in the DFW metropolitan area were studied to determine these effects. Headways were observed for different queue positions including and excluding the effect of heavy vehicles. Analysis of the data did not indicate a significant effect of longer green time when compared with expected values. One signalized intersection approach showed an increase in headway after about 60 s of green time. But this result was not significant in concluding that longer green times had an effect on vehicle headways.
Pilot 05
Authors: Abbas Montasir M. , Charara Hassan A. , Chaudhary Nadeem A.
Published: May 2018

Real-time offset tuning can provide an almost optimal operation while capitalizing on the existing knowledge and familiarity of traffic engineers and personnel with the current actuated control system. The real-time offset tuning concept was introduced several years ago by one of the authors of this paper. Advantages and disadvantages of the concept were discussed in subsequent papers. The concept was taken further for implementation by other researchers within the ACS Lite tactical-level architecture development. This paper describes a parallel effort that focuses more on ( a) a robust classification algorithm of progression quality and remedies and ( b) vendor-independent distributed implementation architecture for the proposed algorithm. Rather than immediate implementation issues, this research establishes a flexible development framework for theoretical development and experimentation of adaptive control algorithms in the context of closed-loop systems operation.
Transition Methods in Traffic Signal Control
Authors: Shelby Steven G. , Bullock Darcy M. , Gettman Douglas
Published: May 2018

“Transition” is simplistically defined as the process of switching from one timing plan to the next. Doing so can disrupt traffic flow to varying degrees, with potentially lasting effects. Avoiding or mitigating these effects is of particular interest in the context of more frequent timing plan changes, as may be expected under traffic-responsive or adaptive traffic control. This paper compares several transition methods, for each of several congestion levels, to determine which methods exhibit the least vehicle delay. A policy is introduced for dynamically selecting an effective transition method based on current traffic conditions. This study uses new transition capabilities recently added to the CORSIM simulation, based on current transition functionality of Eagle, Econolite, NextPhase, and Naztec controllers. Results confirmed that Short-way transition is the most effective in general, but also showed that under congested conditions, Add transition performed as well or better. Dwell transition exhibited higher delays. Evaluation of several parameter settings also demonstrated minor benefits to configuring more generous Add constraints and slightly more conservative Subtract constraints.
Investigation of Portland Cement Concrete Mix Consistency and Concrete Performance Using a Two-Stage Mixing Process
Authors: Rupnow Tyson D. , Schaefer Vernon R. , Wang Kejin , Hermanson Benjamin L.
Published: May 2018

The objective of this study was to investigate the effects of different mixing processes, particularly a two-stage mixing process, on fresh and hardened characteristics of pastes and concrete. Characteristics studied for pastes included rheological effects (i.e., yield stress, thixotropy, viscosity, and peak stress) and compressive strength for mixes prepared in a Hobart mixer and a high-shear mixer. Parameters measured for the concrete study included fresh concrete air and slump, compressive strength, and hardened concrete air void characteristics. The paste study results show that for increased mixing time, the compressive strength is not significantly influenced. The rheology results show that longer mixing times with a high-shear mixer lead to lower viscosity, thixotropy, and peak stress; this indicates better-mixed slurry when compared with a shorter mixing time and the Hobart mixer. The fresh concrete made with the two-stage mixing process shows reduction in air content, and the hardened concrete shows little change in compressive strength when compared with the concrete produced with the one-step mixing process. Rapid air void analysis results indicate that the two-stage mixing method may be beneficial for mixes containing portland cement as a sole binder in freeze–thaw durability.
Measurement of Volume Change in Cementitious Materials at Early Ages
Authors: Sant Gaurav , Lura Pietro , Weiss Jason
Published: May 2018

Early-age cracking in concrete bridge decks, pavements, and superstructure elements has served as the impetus for substantial research on early-age shrinkage in cementitious materials. Much of this research has indicated how mixture proportions, constituent materials, and construction operations can be altered to reduce the risk of cracking. Unfortunately, many unrestrained shrinkage-testing protocols do not provide a comprehensive picture of the early-age shrinkage exhibited by cementitious materials, especially those used in higher-strength concrete. In this paper, the authors review several early-age shrinkage testing procedures. A testing protocol is presented to show how chemical shrinkage can be measured by using buoyancy measurements. A comparison of the measured autogenous shrinkage is made by using four measurement methods: a sealed membrane, a corrugated tube, a noncontact measurement in a rigid mold, and the ASTM C 157 standard. The results of the autogenous and chemical shrinkage tests are compared with one another to describe fully early-age length change. It is shown that through careful experimentation and interpretation, the results of these tests can be completely correlated with one another. This can provide the end user with reliable test procedures to compare different paste compositions and different admixtures and can provide inputs for models that quantify cracking potential.
Evaluation of Mechanical Properties for Self-Consolidating, Normal, and High-Performance Concrete
Authors: Suksawang Nakin , Nassif Hani H. , Najm Husam S.
Published: May 2018

The use of self-consolidating concrete (SCC) is becoming increasingly popular in the United States. Several departments of transportation are currently accepting SCC mix design in some of their projects. Moreover, FHWA is also promoting SCC. However, because SCC is a relatively new material, its mechanical properties and durability are not fully understood. The main objective of this paper is to evaluate and compare the mechanical properties of SCC with normal–conventional concrete, as well as with high-performance concrete. The effect of supplementary cementitious materials on the mechanical properties of SCC is also investigated, and the experimental results of this study are compared to prediction equations. The results show that SCC has a lower modulus of elasticity compared with normal or conventional concrete but higher tensile splitting strength. SCC also has higher drying shrinkage and passes a higher charge (coulombs when using the rapid chloride permeability test).
Comparison of Flatbed Scanner and RapidAir 457 System for Determining Air Void System Parameters of Hardened Concrete
Authors: Carlson Jeremy , Sutter Larry , Van Dam Thomas , Peterson Karl R.
Published: May 2018

Over the past 30 years, a great deal of research has been performed to develop an automated system to perform ASTM C 457, the standard test method for microscopical determination of parameters of the air void system in hardened concrete. The method presented here utilizes contrast-enhanced images created by filling the voids white and coloring the remainder of the hardened concrete surface black. The images were collected with a standard desktop flatbed scanner with an advertised optical resolution capability of 4,800 × 4,800 dpi (∼5.3 × 5.3 micron). Each image took approximately 10 min to collect. The “black and white” contrast-enhanced images were used in conjunction with knowledge of either the mix design or batch weights to perform the calculations set forth in ASTM C 457. Each analysis was accomplished in about 15 to 20 min using a computer script program on a standard personal computer. The same prepared surfaces were also analyzed with a commercially available air void system analyzer. The data collected from the commercial system correlated well with that from the flatbed scanner.
Assessment of Flowable Fill Strength in Pavement Construction
Authors: Lovencin Webert , Najafi Fazil T. , Chaudhry Hammad
Published: May 2018

Flowable fill is a self-compacted, cementitious material used primarily as a backfill in lieu of compacted fill. It generally consists of sand, portland cement, fly ash or slag, and water. It does not settle or require vibration or other means of compaction, it can be excavated, and it is safer than other forms of fill. One approach to predicting its ability to be excavated is to develop a correlation using early-age strength and long-term strength. Flowable fill mixture exhibiting strength less than 0.689 MPa (100 psi) is classified excavatable; mixtures with strengths higher than 0.689 MPa are difficult to excavate and are considered nonexcavatable. Because flowable fill is generally used for backfill and is placed underneath pavement, few studies have been undertaken evaluating moisture effects on long-term strength of flowable fill while underneath pavement. This paper presents the results of a laboratory study evaluating moisture effects on long-term strengths of flowable fill and assesses an accelerated method for predicting its 28-day strength. Samples were cast in limerock bearing ratio cylinders and rectangular wooden molds and were categorized as drained or undrained. Promising results were obtained on how moist environments affect the long-term strength of flowable fill mixtures. Results showed that for an early curing period, the undrained samples exhibited lower strength than drained samples. However, the strength of undrained samples increased with longer periods and to some extent exceeded the drained samples at a 28-day curing period. The accelerated samples had the potential to predict the 28-day strength using an accelerated method.
Driver Response to Rainfall on Urban Expressways
Authors: Unrau Daniel , Andrey Jean
Published: May 2018

The effects of light rainfall on urban freeway operations are modeled to improve understanding of road safety and speed–flow–occupancy relationships in suboptimal weather. Three broader issues also are addressed. What is the form of the relationship among various traffic variables under rainy versus dry conditions? Are the safety implications of driver adjustments under rainy conditions different for the day and night? How should speed variation be measured in ecological studies? Volume–occupancy and speed–volume relationships are affected by rainfall: specifically, speeds are reduced and speed is more strongly dependent on volume. Under nighttime, rainy, uncongested conditions, speeds are reduced and time gaps are increased, but only minimally. Under daytime rainfall conditions, when traffic volumes are typically high, speeds are reduced substantially, and because of the interaction between traffic variables, volumes also decrease. The physical time gap increases marginally as well, whereas speed variability within the traffic stream is reduced. For congested daytime conditions, light rainfall is not associated with any changes in volume or time gap, but speeds are reduced. Finally, safety-related information on speed deviation can be derived from traffic loop data by calculating the variability of travel speeds within small time units.
How Reliable is this Route?
Authors: Dong Jing , Mahmassani Hani S. , Lu Chung-Cheng
Published: May 2018

Schemes are addressed for providing predictive travel time information in consistent anticipatory route guidance systems. A user-equilibrium time-dependent traffic assignment algorithm with the ability for multiple–user class network loading is used to generate consistent anticipatory route guidance information when a fraction of the population is equipped to receive and act on that information. Both a theoretical analysis and a simulation-based approach are presented to evaluate the provision of anticipatory route guidance information in terms of experienced path travel times and their variations. Results indicate that the proposed anticipatory route guidance strategy is accurate and reliable and can improve real-time traffic network performance.
Responses to Enhanced Wildlife Advisories in a Simulated Environment
Authors: Stanley Laura , Hardy Amanda , Lassacher Suzanne
Published: May 2018

Animal–vehicle collisions are a growing concern as vehicle miles traveled and human encroachment into wildlife habitat increase throughout the United States. Transportation agencies may consider driver-based measures to reduce these collisions as an alternative or an adjunct to measures such as fencing and wildlife passages. Driver responses to enhanced wildlife advisories in a simulated environment were examined in the interest of reducing animal–vehicle collisions. Eighty-one participants were divided by age and gender into four groups, each exposed to a different wildlife advisory sign treatment: a standard sign with the text “NEXT 20 MILES,” a standard sign with flashing beacon with the text “NEXT 20 MILES,” a variable message sign (VMS) with the text “ANIMAL CROSSING NEXT 20 MILES BE ALERT,” or a combination of a VMS with the text “ANIMAL CROSSING NEXT 20 MILES BE ALERT,” coming first, and a standard sign with flashing beacon with the text “NEXT 20 MILES” located approximately 6 mi after the VMS. Results indicate that with all enhanced sign treatments, speeds decreased and the onset of braking distance (i.e., reaction time) increased. The standard sign with flashing beacon caused a statistically significant speed reduction over that of the standard sign. The combination of VMS and a standard sign with flashing beacon was “positively identified” most often, resulted in the fewest collisions, and provided the greatest statistically significant onset of braking distance.
Network Expansion Decision Making in Minnesota's Twin Cities
Authors: Montes de Oca Norah , Levinson David
Published: May 2018

A qualitative analysis of the decision rules used by jurisdictions in Minnesota's Twin Cities metropolitan area is presented. Interviews were conducted with staff at the city, county, metropolitan, and state levels to determine how decisions about road investment, expansion, and new construction are made. Flowcharts were developed to provide a more systematic way of presenting that information. Most jurisdictions do not have extensive public participation processes, although several do, notably, the Metropolitan Council, Hennepin County, Ramsey County, and the City of Minneapolis. Jurisdictions with public participation have the most formal and extensive documentation of their investment decision process. The decision factors vary by jurisdiction, though safety, capacity, and pavement quality were important throughout.
Oregon's Transportation Planning Rule Goes into the Shop for Repairs
Authors: McCourt Ransford S.
Published: May 2018

More than 10 years ago, Oregon approved a new and sweeping process for considering transportation planning for local agencies and land use development. This process, coined the Transportation Planning Rule (TPR), was adopted into administrative rules of the state and provided local agencies with a means of considering short-range land use actions, long-range transportation plans, and changes to zoning that have been implemented by local agencies throughout the state. Recently TPR has been challenged over its process for addressing the relationship between the adequacy of transportation facilities and rezoning of land uses. The Jaqua case, taken to the State Court of Appeals, raised key issues as to the level of evaluation and planning process necessary in determining the adequacy of transportation facilities: a property owner challenged a city's transportation analysis in support of a land use rezoning action and claimed that analysis was not adequate because it did not look incrementally over time (similar to concurrency) but at the end planning horizon year (20 years in the future). The state has convened a blue-ribbon panel to assess the issues associated with the implementation of TPR and how transportation policy may need to be refined to address both the long-term planning goals and development implementation interests best. At stake is the level of transportation analysis necessary to address changes in land use from approved plans. The issues associated with updating Oregon's Transportation Planning Rule, including the stakeholder process, blue-ribbon panel, study findings, and implementation of one of the country's most unusual statewide transportation policies, are outlined. The land use and transportation issues are explored from multiple perspectives such as land development, local agency, public needs, and transportation analyst.
Public Involvement Practices and Perspectives of Florida's Metropolitan Planning Organizations
Authors: Hopes Christina , Kramer Jeff , Williams Kristine
Published: May 2018

Results from a statewide survey on current public involvement practices of Florida's metropolitan planning organizations (MPOs) are described. Of Florida's 26 MPOs, 25 responded to the six-page electronic survey. Overall, the most commonly used techniques were newsletters and public meetings, followed closely by brochures, individual and small-group briefings, and newspaper advertisements in general circulation publications. Although public meetings and hearings were widely used, many MPOs identified them as their least-effective public involvement technique and emphasized the importance of “going to the public, rather than asking people to come to you.” Most respondents indicated that they would rate the public's response to their public involvement process as favorable or better, but nearly as many said that they would rate the public's response to their process as fair. Florida MPOs believed that the greatest challenges they face in the public involvement process include poor attendance at meetings (60%), lack of adequate resources (i.e., staff or funding) (56%), lack of public understanding of the transportation planning process (48%), and difficulty involving people in the early planning process (44%). Despite such challenges, MPOs responding to the survey acknowledged the benefits of an effective public involvement process, including improved relationships with affected citizens and interested parties (76%), improved public understanding of the transportation planning process (72%), improved public trust–credibility of the agency (60%), better projects–more effective transportation solutions (44%), and fewer adverse impacts on the community or the environment (44%).
Motorist Yielding to Pedestrians at Unsignalized Intersections
Authors: Turner Shawn , Fitzpatrick Kay , Brewer Marcus , Park Eun Sug
Published: May 2018

This paper evaluates engineering treatments that can be used to improve the safety of pedestrians crossing in marked crosswalks on busy arterial streets. The research team collected extensive data at 42 study sites in different regions of the country to gauge the effectiveness (as measured by motorist yielding or stopping) of various engineering treatments. Motorist yielding data were collected for crossing pedestrians from the general population as well as for crossings staged by the research team. In preliminary analyses, the treatments were grouped into three categories based on function and design: ( a) red signal or beacon devices, ( b) “active when present” devices, and ( c) enhanced and high-visibility treatments. The authors found the red signal or beacon devices to be the most effective, with yielding rates exceeding 94% for all study sites. Other treatments had various rates of motorist yielding, and several variables (number of lanes and speed limit in particular) were statistically significant in predicting motorist yielding. Most treatments in the other two categories had statistically similar motorist yielding levels. An implementation matrix (currently being finalized by the research team) is recommended to assist in selecting appropriate crossing treatments for streets with known road widths, traffic volumes, and pedestrian volumes. It is recommended that engineers include red signal or beacon devices in their toolboxes to improve pedestrian crossing safety along busy arterial streets.
From TIGER to Audit Instruments
Authors: Schlossberg Marc
Published: May 2018

The relationship between urban form and pedestrian mobility is an area of increasing policy interest within the planning, transportation, environmental, and public health fields. Many municipalities are seeking to adopt variations of smart growth principles that seek, in part, to increase pedestrian choice in an urban environment. This paper explores how the path network around key urban destinations can be visually and quantitatively analyzed to provide useful planning and evaluation tools for these pedestrian-oriented environments. Neighborhood environments surrounding transit stops and schools are used as examples of how to visualize and quantify local walkable environments. Three key techniques based on geographic information system (GIS) are presented: street network classification, pedestrian catchment areas, and intersection intensities. Although such measures have been used elsewhere to some extent, this paper includes the idea of impedance, a method to help distinguish between automobile-oriented and pedestrian-oriented areas. A series of GIS-based qualitative visualization and quantitative analyses are presented, as are some basic steps on conducting the analyses within a GIS environment. A discussion of key data sources, including TIGER (topologically integrated geographic encoding and referencing) street data and new pedestrian audit instruments, are also presented as different ways to assess local walkability.
Index for Assessing Pedestrian Safety at Intersections
Authors: Zegeer Charles V. , Carter Daniel L. , Hunter William W. , Stewart J. Richard , Huang Herman , Do Ann , Sandt Laura
Published: May 2018

The primary objective of this study was to develop an index that would allow engineers, planners, and other practitioners to prioritize intersection crosswalks with respect to pedestrian safety. The study involved collecting data on pedestrian crashes, conflicts, and avoidance maneuvers as well as subjective ratings of intersection video clips by pedestrian professionals. Sixty-eight pedestrian crosswalks were selected for the pedestrian analysis from Philadelphia, Pennsylvania; San Jose, California; and Miami–Dade County, Florida. A predictive model, the pedestrian intersection safety index (Ped ISI), was developed primarily on the basis of intersection ratings and avoidance maneuvers. Variables in Ped ISI included the number of through lanes, 85th percentile vehicle speed, type of intersection control (signal or stop sign), main street traffic volume, and area type. Through a user-friendly guide, Ped ISI can be used to identify which crosswalks in a city have the highest priority for pedestrian safety improvements. Specific countermeasures can then be implemented to reduce certain types of hazards. This tool should also be helpful in influencing future intersection design.
Pedestrian Push-Button Confirmation Increases Call Button Usage and Compliance
Authors: Van Houten Ron , Ellis Ralph , Sanda Jose , Kim Jin-Lee
Published: May 2018

Many pedestrian crashes involve pedestrians crossing during the don't walk signals for pedestrians. The purpose of this study was to evaluate the effects of push buttons that give visual and audible feedback when they have been pressed on the proportion of pedestrians who press the call button and the proportion of pedestrians pressing the call button who wait for the walk sign. Data were collected at two busy intersections in Miami Beach, Florida, with relatively high daily traffic flows. The installation of push buttons that provided visual and audible feedback was associated with a statistically significant increase in the percentage of cycles in which pedestrians pressed the button as well as a significant increase in the percentage of pedestrians pressing the button who waited for the walk sign. Because behavior changed only when the new push buttons were installed and the push buttons were installed at a different point in time at each site, it was possible to rule out potential confounding variables such as weather, traffic flow, and changes in the demographic characteristics of the pedestrian. The percentage of pedestrians trapped in the roadway was also lower when pedestrians waited for the walk sign during baseline. After the new push buttons were installed, the percentage of trapped pedestrians decreased. Because push buttons that emit a visible and audible cue when they are pressed are relatively inexpensive, this treatment is a cost-effective way to increase the percentage of pedestrians who press the button and wait for the walk sign before crossing. Accessible push buttons also acknowledge they have been pressed. These data indicate that accessible buttons may benefit all pedestrians.
Characteristics Related to Midblock Pedestrian–Vehicle Crashes and Potential Treatments
Authors: Sandt Laura , Zegeer Charles V.
Published: May 2018

Reducing pedestrian crashes is a top priority for transportation professionals. Pedestrian crashes at midblock locations occur frequently and need further investigation. The purpose of this exploratory study is to understand the characteristics of midblock pedestrian crashes to determine appropriate safety treatments. The primary objective was to compare midblock and intersection crashes in light of their roadway characteristics, environment, and characteristics of the involved parties to provide information on the most common factors related to midblock crashes. Databases from Kentucky, Florida, and North Carolina were used to determine which crash variable categories have significantly higher proportions at midblock locations as opposed to intersections. The distribution of crashes was compared across the two groups. The results of a t-test determined the significance of differences of means observed between the two crash groups. Several variables (such as lighting conditions and divided versus undivided roads) are similarly distributed among midblock and intersection crashes. Furthermore, the study highlighted the categories within the variables tested with significantly higher proportions in midblock crashes as opposed to intersection crashes in one or more of the databases. These include two-lane roads, younger male pedestrians involved in the crash, residential land use patterns, and rural crash locations. This paper identifies areas and variables where further research is appropriate, particularly with respect to determining safety treatments for midblock locations.
Geographic Information System Analysis of Accessibility as Indicator of Potential Land Use Changes and of Induced Impacts on the Environment
Authors: Vicente Alfredo Sánchez , Martín Clara Zamorano
Published: May 2018

This paper describes the application of geographic information system methodology in the appraisal—as an approach on a strategic scale—of the characteristics of a territory likely to be affected by new land transportation infrastructures across particularly sensitive areas. The chosen scope of study covers the Pyrenean region, which marks the border between France and Spain and is considered one of Europe's richest enclaves from an environmental viewpoint. The analysis focuses on the identification of areas where induced impact on the environment could be higher and therefore where focus should be placed on the assessment. This focus was made possible by the construction of an environmental quality map—through the integration of a number of theme maps for different environmental variables—covering the entire area under study. At the same time, a calculation model was built to determine the accessibility before and after construction of the proposed transportation infrastructures. The combination of accessibility and environmental quality maps provides useful results to improve the strategic environmental assessment process by incorporation of indirect effects. To discuss the likely implications of a rise in accessibility and as a test for the indicator used, an analysis of land use changes for the period from 1992 to 2004 has also been done for a smaller area where a motorway was built in the late 1990s; this analysis provides an idea of the potential development of the area and a good amount of data for discussion.
Simplified Analysis Method for Natural Dispersion of Highway Storm Water Runoff in Rural Areas
Authors: Reister Mitchell S. , Fiedler Fritz R.
Published: May 2018

Storm water quantity control has long been a challenge for highway designers. Traditionally, centralized best management practice designs are often cost prohibitive and inefficient in many rural highway applications. The use of existing vegetated rights-of-way as a method of treating storm water, a component of the broader storm water treatment concept more generally referred to as low-impact development, has become a primary focus of the Washington State Department of Transportation. To design and use such storm water management controls adequately, however, further research and correlation between numerical infiltration–runoff models and field experiments were needed. This paper focuses on evaluating natural dispersion performance through the use of simulated rainfall runoff data collected with a field-scale rainfall simulator and a numerical model to study the effects of slope length, angle, and impervious contributory area on natural dispersion applications. A simple new equation was developed to analyze natural dispersion performance on the basis of multiple variables. The research and resulting evaluation procedure indicated that the use of natural dispersion as a storm water quantity control strategy is applicable to many roadside areas in Washington State.
Use of Gas Cushions for Field Measurement and Analysis of Hybrid Vibration Isolation Wall
Authors: Kanda Hitoshi , Ishii Hirotoshi , Yoshioka Osamu
Published: May 2018

Ground vibration induced by traffic, such as occurs on roads, highways, and railroads, may become a nuisance to nearby inhabitants and buildings. These problems have recently increased, especially in urban areas as higher environmental quality is required. Although many efforts have been made to mitigate ground vibration, in some cases, more powerful measures are needed. In this paper, a three-layered hybrid-type vibration isolation wall that uses gas cushions was developed. To confirm the vibration isolation performance of this wall, field experiments were conducted. Ground vibration generated by a mechanical oscillator was measured before and after the construction work at the same points. Ground deformation was also measured when the wall was built and when some cushions burst. It became clear from the measurements that the wall was as effective as open trenches, especially in lower frequencies such as 5 to 10 Hz. On the basis of the findings, vibration isolation effects are highly recommended.
Environmental Justice Concentration Zones for Assessing Transportation Project Impacts
Authors: Victoria Isabel C. , Prozzi Jolanda , Walton C. Michael , Prozzi Jorge
Published: May 2018

Environmental justice (EJ) becomes a concern when minority or low-income communities (referred to as EJ populations) are disproportionately affected by transportation projects. The disproportionate impacts may relate to social, economic, or environmental burdens that EJ populations living in affected project areas will be forced to endure. An important component of any EJ assessment methodology is therefore the identification of EJ communities in a project area. The conventional approach classifies communities by means of threshold values into target and nontarget EJ populations. Research has demonstrated, however, that threshold values are largely influenced by the chosen community of comparison. In addition, the spatial distribution of target and nontarget EJ populations within the affected area changed when the scale of geographic analysis changed. Because it has been argued that effective EJ analysis should consider all minority and low-income population groups regardless of their size, this research presents an innovative approach to identify the concentration of EJ individuals in affected project areas. The approach consists of five steps. First, the spatial distribution of minority and low-income populations is estimated by means of census data at the block level. Second, local measures of spatial autocorrelation for EJ populations are computed for each census block. Third, the EJ concentration levels are conceptualized on the basis of spatial-cluster patterns. Fourth, the concentration levels of minority and low-income populations are combined into a single raster model. The outcome is a map in which each cell has a value that represents its concentration level. Finally, these values and specified spatial connectivity criteria are used to define EJ concentration zones. The objective of this paper is to describe the approach and to present the results from testing it.
Interagency Development of Performance Standards for Managing Materials, Wastes, and Contamination under Oregon's Bridge Program
Authors: Armstrong Jennie E. , Levine Ann
Published: May 2018

In 2003, Oregon's legislature passed and funded a transportation initiative that provided $1.3 billion for a bridge repair and replacement program, tripling the Oregon Department of Transportation's (ODOT) construction funding. That same year, a governor's executive order directed ODOT to develop sustainability measures for that program. Therefore, ODOT requested the assistance of the state department of environmental quality (DEQ) in developing performance standards that ensure regulatory compliance and facilitate environmental stewardship. DEQ realized that the proposal could help it meet its agency goals, and the two agencies signed an agreement under which ODOT paid DEQ staff to help develop the performance standard and DEQ absorbed the costs of senior management review. The ODOT-DEQ team developed performance standards that provide consistent regulatory interpretations specific to bridge construction, promote reuse over virgin materials, provide materials handling and waste management guidance for common bridge materials, ensure contamination is identified before construction, and facilitate data sharing with DEQ. The team provides a hierarchy for waste management and materials procurement practices that encourages consideration of more environmentally beneficial options when those are technically and financially feasible. The development process has already had the benefit of improving interagency relationships. Implementation should also improve regulatory compliance, increase reuse and recycling, decrease land filling, and improve air quality, all without increasing overall project costs. Implementation may even reduce costs through decreased transportation, landfill fees, virgin materials costs, and time that would have been needed to negotiate alternative material uses and permits for each project.
Design, Development, and Qualification of New Guardrail Post
Authors: Kennedy James C. , Plaxico Chuck A. , Miele Charles R.
Published: May 2018

The basic design concepts for strong-post w-beam guardrail systems were developed more than 30 years ago. Although the vehicle fleet today differs significantly from vehicles for which the systems were designed, those systems are still in widespread use. One of the changes in the vehicle fleet with the most influence on the performance of guardrails and other safety barriers is the emergence of pickup trucks and SUVs. These vehicles are heavy and have relatively high centers of gravity, so in addition to overloading the guardrail, such vehicles are highly unstable during redirection and are likely to roll over. One of the most serious problems with these systems is the front impact-side wheel snagging on the guardrail posts. Conventional post types used in strong-post guardrail systems consist of either large wooden posts or steel I-beam section posts, both of which are unforgiving when impacted by a wheel. Recently, HALCO, LLC, developed the HALCO X-44 post, a guardrail post that is lightweight, strong, and designed to be used in strong-post w-beam guardrail applications as an alternative to conventional post types. The X-44 post was designed to be more forgiving when crashed into by the wheel of a vehicle, yet strong enough to limit guardrail deflection under NCHRP Report 350 Test Level 3 impact conditions. In this study the HALCO X-44 post was evaluated in a length-of-need section of w-beam guardrail. A finite element model of the guardrail system was developed, and the finite element program LS-DYNA was used to assess its performance under NCHRP Report 350 Test 3-11 impact conditions. A full-scale crash test was subsequently conducted after favorable results from the finite element analysis. The system successfully passed the safety requirements of NCHRP Report 350 for Test Level 3. This paper discusses the evaluation procedure and presents results of the HALCO X-44 post and guardrail system analysis.
Approach to Greenways and Natural Paths in Spain
Authors: Cordón Sergio Rodríguez , Guerrero Ignacio Cañas
Published: May 2018

Greenways and natural paths are a way of providing enjoyment, promoting the cultural and landscape knowledge of an area, providing exercise, and encouraging respect for the environment. The aim of this paper is to analyze some physical characteristics of greenways and natural paths in Spain. The paper's introduction clarifies some concepts and provides historic references. To achieve the objective of this pilot study, successive meetings with representatives of the Spanish Ministry of the Environment and the Spanish Railway Foundation were held to learn about previous projects. After some of these projects were reviewed, various characteristics of the paths, including users of the paths, typology of the platform, and reforestation, were analyzed. Results of the analysis are presented in tables, which show that greenways tend to be more uniform than natural paths, which have more variable features. After the analysis, the most common characteristics of Spanish natural paths and greenways are presented.
Alternative Measure of Household Structure and Stage in Life Cycle for Transport Modeling
Authors: Richardson A. J.
Published: May 2018

A new concept in describing the structure of households is introduced. The average age of the household, as well as its relationship to the age of the individual, is shown to have some interesting and consistent properties that provide greater insight into the structure of households, particularly as an individual grows older. The relationships between age of the individual and average age and size of the household are shown to provide extra information to that contained in more conventional descriptive measures of household structure. In addition, with a model of trip generation based on chi-square automatic interaction detection, the average age of the household, along with its relationship to the age of the individual, is shown to be a more significant predictor of daily trip rates than some more conventional measures of household structure. It is shown that despite its computational simplicity, the new variable has promise in describing household structure and changes in life cycle and that further investigation of the properties of the variable should be undertaken.
Order Effects in Stated-Choice Experiments
Authors: Van Der Waerden Peter , Borgers Aloys , Timmermans Harry , Bérénos Mike
Published: May 2018

Results are presented from a study of possible order effects in stated-choice experiments tested in the context of transport mode choice decisions. A stated-choice experiment with three alternatives—car, public transport, and bicycle—is used to analyze whether the sequence in which choice sets are presented influences the estimated utility functions of transport modes. The data were collected by means of a self-administered mail questionnaire. More than 950 respondents participated in the experiment. The analyses show that order effects are relatively small but significant. The appearance of the public transport alternative before the bicycle in the choice task influences the utility of public transport significantly. Order effects depend on trip purpose.