bluuebunny/crossref_metadata_2025 huggingface dataset:
Laboratory Characterization of Recycled Concrete for Use as Pavement Base Material
Authors: Blankenagel Brandon J. , Guthrie W. Spencer
Published: May 2018

The purpose of this research was to characterize both demolition and haul-back sources of recycled concrete material (RCM) available in Utah County, Utah, for use as pavement base material and to investigate the self-cementing behaviors of each. A telephone survey was conducted to assess the state of the practice with respect to the local use of RCM, and extensive laboratory testing was performed to evaluate the strength and durability properties of both sources of RCM. Laboratory testing included determinations of particle-size distributions, Atterberg limits, specific gravity values, absorption characteristics, moisture–density relationships, California bearing ratio (CBR), unconfined compressive strength (UCS), stiffness, resistance to freeze–thaw cycling, tube suction test (TST) moisture susceptibility classifications, and Los Angeles abrasion losses. The results of the testing indicate that marked stiffening and strength gain of the materials occur within a 7-day curing period, although the rate and extent of the increases are dependent on the material source. The higher fines content of the haul-back material corresponded to higher absorption, optimum moisture content, maximum dry density, CBR, UCS, and stiffness values compared with the demolition material, presumably because of the exposure of greater quantities of unhydrated cement in the production of the haul-back RCM. However, the haul-back RCM was characterized by a greater loss in stiffness after freeze–thaw cycling and received a marginal moisture-susceptibility rating in the TST, while the demolition RCM was rated as non-moisture-susceptible. Further research is needed to more definitively investigate the self-cementing mechanism of RCM.
Laboratory Assessment of Coarse Granular Road Foundation Materials
Authors: Lambert J. P. , Fleming P. R. , Frost M. W.
Published: May 2018

A new performance-based specification for road foundations in the United Kingdom potentially allows any material that is “fit for purpose” and encourages the wider use of marginal and recycled–secondary materials. The specification provides guidance with respect to target stiffness, density achieved, and maximum allowable rutting depth under construction traffic (to avoid damage to the subgrade during construction). Full-scale field trial sections are proposed for large schemes to ensure the suitability of proposed foundation materials. However, it is prudent to develop a routine, economical, and laboratory-scale means of assessing the performance and suitability of the foundation materials before any full-scale trials are undertaken. This paper presents the findings of recent research work at Loughborough University with regard to the development of a large-scale laboratory assessment test designed specifically for granular materials. A series of tests done on four granular materials is presented in detail, with an emphasis on their stiffness behavior. Some field data are given for comparison, and a preliminary validation of the laboratory method is given as well. The effects of a soft and rigid base condition and of wetting and drying of the material is shown to have a significant effect on the measured values of both stiffness and strength for the samples tested. However, there appears to be a reasonable relationship between the laboratory results for the soft base condition and the field data. Several recommendations for further work are made, and practical observations and comments are given regarding the construction and measurement of these materials on site within a performance-specification framework.
Performance Evaluation and Numerical Modeling of Embankment over Soft Clayey Soil Improved with Chemico-Pile
Authors: Hossain Sahadat , Rao Krishna Nag
Published: May 2018

The stabilization of soft clay is one of the most important construction techniques in geotechnical engineering. The injection method using chemical grouting in the ground has been widely used to improve soft ground. Chemical admixture stabilization (with lime and cement as the chemical admixture) has been extensively used in both shallow and deep stabilization to improve the inherent properties of soil, such as strength and deformation behavior. These methods involve mixing soil with chemicals. The other technique—the so-called chemico-lime pile or chemico-pile method—involves forming columns of chemically treated lime in the soil without mixing. This method is widely used in Japan and Singapore and is a fast, effective, and well-recognized way of improving soil with soft clay deposits. The chemico-pile method has been used in a full-scale test embankment project at the Nong Ngo Hao site near Bangkok, Thailand. The site is part of the second Bangkok International Airport project, located in the Samutprakan Province, 30 km east of the Bangkok metropolis. Both laboratory and field investigations were performed to evaluate the effectiveness of lime columns on soft soil. In situ cone penetration tests were performed to evaluate the reduction in compressibility and the increase in the shear strength of the soils. Numerical modeling using the finite element program PLAXIS was employed to model the chemico-pile–supported embankment. This paper presents the improved effect of chemico-pile on soft clay, discusses the improved embankment behavior seen in the field data, and compares the field data with numerical modeling results for pore water pressure, vertical settlements, and lateral movements.
Effect of Aggregate Gradation, Mineral Fillers, Bitumen Grade, and Source on Mechanical Properties of Foamed Bitumen–Stabilized Mixes
Authors: Saleh Mofreh F.
Published: May 2018

With the rapid growth of traffic volumes and axle loads, the use of efficient and cost-effective stabilization methods is imperative. The use of foam bitumen stabilization is rapidly growing because of its environmentally friendly benefits and its high field performance properties. In this study, a detailed investigation of the mechanical properties of foam-stabilized mixes was carried out. The experimental work presented compares the mechanical properties of foam-stabilized mixes created with two different gradations and eight bitumen types from six different sources. Different types of mineral fillers, including hydrated lime, fly ash type C, portland cement, and pond ash, were used in the mix design. The volumetric properties, resilient moduli, indirect tensile strengths, fracture energies, and California bearing ratio (CBR) values were investigated. Temperature and moisture susceptibilities were studied and compared for different types and grades of bitumen. Foam-stabilized mixes provided lower temperature susceptibility than did hot-mix asphalt. The effect of bitumen source and grade on moisture susceptibility was inspected. The foam-stabilized mixes provided reasonable moisture resistance as the index of retained strength exceeded 80% to 90% after 5 days of soaking. The effect of aggregate gradation and mineral fillers on the indirect tensile strength and the fracture energy was evident. Hot-mix asphalts provided higher tensile strength and fracture energy than did foam-stabilized mixes. Foamed bitumen stabilization significantly enhanced the CBR values as the soaked CBR of foam-treated specimens provided higher CBR values than the conventional untreated aggregates.
Full-Scale Accelerated Testing of Flexible Pavements Made of Coal Combustion Products
Authors: Tu Wei , Zand Behrad , Wolfe William E. , Butalia Tarunjit
Published: May 2018

Increasing environmental concerns and diminishing landfill space coupled with the rising costs of natural resources consumed in road construction have encouraged researchers to investigate the use of recycled materials in pavement design. This investigation evaluated the performance of full-scale asphalt pavements made with recycled coal combustion products (CCPs) during accelerated pavement testing. Three instrumented pavement sections—two CCP sections and one conventional section—were constructed and tested at the Ohio accelerated pavement loading facility (APLF). All three pavement sections were subjected to the equivalent of 20 years of traffic on a typical state route in Ohio. To minimize the environmental effects, both ambient temperature and moisture were controlled throughout the loading period. Pavement response and performance and environmental conditions were monitored. Based on the data collected, the CCP base–subbase mixtures outperformed the control mix in terms of measured pavement response and higher pavement stiffness, as exhibited by the falling weight deflectometer (FWD) testing results. At the end of accelerated loading, the moduli of the two CCP base–subbase mixtures, as backcalculated from the FWD tests, were up to three times higher than that measured for the control section.
Evaluation of Chemically Stabilized Clay Soil Embankments with Accelerated Pavement Testing
Authors: Romanoschi Stefan A. , Banda Sathish , Hossain Mustaque , Gisi Andrew J.
Published: May 2018

The Midwest States Accelerated Pavement Testing Pooled Fund Program, financed by the highway departments of Missouri, Iowa, Kansas, and Nebraska, has supported an accelerated pavement testing project to compare the performance of stabilized clayey embankment soil when portland cement, fly ash, lime, and a commercial product were used as stabilizing agents. The project aimed to determine if lime stabilization, the most common method used in Kansas for the chemical stabilization of embankment soils, is the optimum method. The experiments were conducted at the Civil Infrastructure Systems Laboratory of Kansas State University. The test program consisted of constructing four pavement structures and subjecting them to full-scale accelerated loading. The study indicated that cement and lime are the most effective stabilizers. These stabilizers resulted in lower vertical compressive stresses at the top of the subgrade and lower rut depth at the pavement surface than the stresses and depth resulting from fly ash–treated soil. After more than 2 million axle load repetitions, the pavement with cement-stabilized embankment soil exhibited much less surface cracking than did the pavement with fly ash–stabilized embankment soil. The commercial product proved ineffective in stabilizing the nonsulfate clayey soil used in this experiment, when the embankment was constructed at the same moisture content and compaction level as for the other three chemicals. The unconfined compression strength measured on laboratory-prepared samples of soil stabilized with the commercial chemical compound was very similar to that of the untreated soil.
Assessing Crash Occurrence on Urban Freeways by Applying a System of Interrelated Equations
Authors: Abdel-Aty Mohamed , Pemmanaboina Rajashekar , Hsia Liang
Published: May 2018

Most existing freeway crash frequency models analyze overall frequency of crashes. Furthermore, researchers have traditionally used average annual daily traffic (AADT) to represent traffic volume in their models. These two cases are examples of macroscopic crash frequency modeling. Segregating crashes on the basis of type of crash, peak or off-peak traffic conditions, lighting conditions, severity, and pavement condition could provide insight into the specific factors that affect each category. In this study multiple binary categorizations of the crashes were created to identify the factors associated with their frequencies and used geometric characteristics of the freeway and microscopic traffic variables that were based on loop detector data. These categorizations included multiple- and single-vehicle crashes, peak period and off peak period crashes, dry and wet pavement crashes, daytime and dark-hour crashes, and property-damage-only and injury crashes. Models for frequency of each of the two groups of crashes were estimated separately for all five categorizations. To account for correlation between the disturbance terms arising from omitted variables between any two models in a category, seemingly unrelated negative binomial (SUNB) regression was used for simultaneous estimation. SUNB estimation proved to be advantageous for multiple- and single-vehicle crashes and for daytime and dark-hour crashes. Road curvature and presence of on- or off-ramps were found to be the significant factors related to every crash category. Median type and pavement surface type were among other important factors affecting crashes. AADT was significant in most models and the 15-min coefficient of variation of speed was significant for frequency of daytime and peak period crashes. SUNB estimation proved to increase the efficiency of the crash frequency models by accounting for the disturbance correlation, reducing the standard errors, and providing better model fit.
Applying Variable Speed Limits and the Potential for Crash Migration
Authors: Abdel-Aty Mohamed , Dilmore Jeremy , Hsia Liang
Published: May 2018

Variable speed limits (VSL) were applied on I-4 in Orlando, Florida, through microsimulation to reduce crash likelihood. VSL application improved safety by simultaneously implementing lower speed limits upstream and higher speed limits downstream of the location where crash likelihood was observed in real time. Real-time crash likelihood was calculated with the use of models developed in previous research. The improvement was realized in the case of medium- to high-speed regimes on the freeway, but no benefit was achieved in low-speed situations; that is, there was no substantial safety benefit from applying VSL in congested situations. In addition to the safety benefit, travel time was also reduced. The simulation results showed a potential for crash migration. The crash potential appeared to relocate to a location downstream of the detector of interest. Upstream, little change occurred, except at the location where the change in speed took place. While there are some crash migration effects, the overall safety of the freeway was improved due to VSL application.
Potential Real-Time Indicators of Sideswipe Crashes on Freeways
Authors: Lee Chris , Abdel-Aty Mohamed , Hsia Liang
Published: May 2018

This study investigates the real-time traffic factors associated with sideswipe crashes, including a surrogate measure of lane change and compares conditions for sideswipe and rear-end crashes on the basis of these factors. This study extends a previous experimental study of lane change by suggesting that a geometric mean of ratios of flows between adjacent lanes called the overall average flow ratio (OAFR) can be used to indicate the likelihood of sideswipe crashes given that a crash is likely to occur. OAFR was calculated for 5 to 10 min before crash occurrence at a location upstream of crash sites. Using 4-year crash and loop detector data on a 36.3-mi section of I-4 freeway in Orlando, Florida, the study found that OAFR was generally higher for sideswipe than rear-end crashes at a 95% confidence level. Analysis using logistic regression models showed that other traffic-related factors, such as the variation in flow and peak and off-peak periods, were also important factors correlated with sideswipe crashes. The findings in this study suggest that the model is potentially capable of predicting the risk of specific types of crashes, not only generic crashes, through use of real-time traffic flow data on freeways.
New Approach to Accident Analysis for Hazardous Road Locations
Authors: Elvik Rune
Published: May 2018

This paper proposes a new approach to the analysis of accidents at hazardous road locations, one that is designed to make these analyses more effective in discriminating between true and false positives, that is, sites whose true expected number of accidents is high and sites where a high recorded number of accidents is predominantly the result of chance variation. The following elements of the proposed approach have not traditionally been part of the analysis of accidents at hazardous road locations: (a) the use of a binomial probability model to estimate the probability that the observed pattern of accidents at a hazardous road location differs from the normal pattern for comparable sites; (b) a two-stage procedure for analysis, in which the first stage consists of an analysis of accidents designed to develop hypotheses about risk factors contributing to the accidents and the second stage is designed to test these hypotheses; (c) the use of a matched-pair, single-blind method for evaluating risk factors that contribute to accidents at hazardous road locations; and (d) the development of clear criteria for concluding whether an apparently hazardous road location actually is. These elements are designed to guard against some pitfalls of the traditional approach to accident analysis for hazardous road locations, including confirmation of analyst expectancies, data mining, and nonspecific criteria for determining whether a hazardous road location is a true or false positive. The approach is illustrated through simulated data.
Influence of Land Use, Population, Employment, and Economic Activity on Accidents
Authors: Kim Karl , Brunner I. Made , Yamashita Eric Y.
Published: May 2018

In this study, the relationships between land use, population, employment by sector, economic output, and motor vehicle accidents are explored. Through the use of comprehensive data from the largest county in Hawaii, the relationships are modeled in a uniform 0.1-mi2 (0.259-km2) grid structure and with various linear regression models. This method has an advantage over other approaches that have typically used unevenly sized and shaped traffic analysis zones, census tracts, or block groups. Positive, statistically significant relationships among population, job counts, economic output, and accidents are identified. After some of the general effects are sorted through, a negative binomial (NB) model is used to look at the absolute and relative effects of these factors on the number of pedestrian, bicycle, vehicle-to-vehicle, and total accidents. With a multivariate model, the different effects can be compared and the specific nature of the relationships between zonal characteristics and accidents can be identified. While there is, in general, a significant relationship between all these values, the effects are more pronounced with vehicular crashes than with those involving pedestrians or bicyclists. In addition to the general effects, the influences of employment, economic development, and various activities on the level and type of accidents are investigated. Some challenges associated with modeling these relationships are described, as are implications for traffic safety research. The paper adds to the growing volume of traffic safety research integrating NB regression models and geographic information systems.
Reanalysis of Hutchinson and Kennedy's Encroachment Frequency Data
Authors: Davis Gary A. , Morris Paul M.
Published: May 2018

Predicting the frequency of roadside encroachments is a necessary first step to analyzing the costs and benefits of a proposed roadside improvement. The results of the classic Hutchinson and Kennedy study, which analyzed encroachments onto the median of divided highways, have been used for this purpose. That study asserted that encroachment frequencies have a nonlinear dependence on average daily traffic (ADT) such that there is a decrease in encroachment rate for roadways carrying between 4,000 and 5,000 vehicles per day. A review of the data from that study has revealed that the ADT counts were confounded with time, over which the observed encroachment rate varied. With the use of statistical techniques not available to that study's authors, it was shown here that the assertion of ADT dependence is not well supported and that the observed changes in encroachment frequencies can also be explained by a simple model consisting of a time trend and an effect due to winter weather. The resulting recommendation is that only the portion of Hutchinson and Kennedy's study yielding a relatively constant encroachment rate be used in future analyses of roadside safety improvements.
Rural Expressway Intersection Characteristics as Factors in Reducing Safety Performance
Authors: Burchett Garrett D. , Maze T. H.
Published: May 2018

Expressways have been constructed in many states as a way to increase mobility without the expense of a full access-controlled grade-separated facility. In most cases, it was assumed that these segments of highway would produce similar mobility and safety characteristics as other access-controlled facilities. However, recent research has found that there are problems with the safety performance of these systems. The objective of these analyses is to identify the major contributing factors that create problematic intersections in Iowa. From previous research, it is evident that factors in addition to roadway volume contribute to the safety performance of an at-grade, two-way, stop-controlled expressway intersection. This research identifies additional characteristics that may increase or decrease the safety performance of a rural expressway intersection. The methodology used in this research includes the examination of 644 intersections throughout Iowa. Through the use of a statewide database and crash information from 1996 to 2000, it was possible to identify, on the basis of crash severity rate, the 100 best-performing and 100 worst-performing expressway intersections. With these 200 intersections, a statistical analysis was completed to determine the effects intersection design and surrounding land use have on an intersection's safety performance. Skewed intersections, intersections located on vertical or horizontal curves, and intersections at which there is varying surrounding land use were studied to determine their effects on safety performance. Following the completion of the analysis of the 200 intersections, the 30 intersections with the highest crash severity index rates were selected for more thorough, site-specific analysis. As part of this analysis, the authors examined the impact of land use adjacent to the intersection and of peaking in hourly traffic volumes. The research identifies attributes that impact crash frequency and severity both negatively and positively.
Evaluation of Safety Effects of Driver Assistance Systems through Traffic Simulation
Authors: Lundgren Jan , Tapani Andreas
Published: May 2018

Road safety is a major concern in all countries, and large efforts are constantly dedicated to create safer traffic environments. Today increasing attention is turned toward active safety improving countermeasures that improve road safety by reducing accident risks. Such active countermeasures include advanced driver assistance systems (ADAS). To ensure that these new applications result in real safety improvements, a priori estimations of safety effects are needed. This paper considers estimation of the safety effects of ADAS through traffic simulation. Requirements imposed on a traffic simulation model to be used for ADAS evaluation are presented, and a car-following model to be used in simulations that include ADAS-equipped vehicles is proposed. ADAS have an impact on traffic through the functionalities of ADAS and through changes in driver behavior for ADAS-equipped vehicles. Driver behavior for ADAS-equipped vehicles has usually not been considered in previous simulation studies, including those for ADAS-equipped vehicles. Simulation runs of rural road traffic that used the proposed car-following model did, however, indicate that behavioral changes caused by the ADAS were important factors for the safety impact. Modeling of the behavior of drivers in ADAS-equipped vehicles is therefore essential for reliable conclusions on the road safety effects of ADAS.
Practical Method for Estimating Frequency of Right-Angle Collisions at Traffic Signals
Authors: Songchitruksa Praprut , Tarko Andrew P.
Published: May 2018

Statistics indicate that accidents at signalized intersections have become a significant safety problem throughout the United States. Right-angle collisions are ranked highest in terms of severity at signalized intersections, while their frequency is second only to rear-end collisions. One key component that is lacking is a tool to help identify excessive risk of right-angle collisions. This paper proposes a practical method to evaluate the frequency of right-angle collisions on the basis of the frequency of short postencroachment times (PET). PET and crash data collected from signalized intersections in Indiana were used to calibrate right-angle crash prediction models. Regression results reveal that PET frequency is a key determinant of right-angle crashes and is capable of discriminating varying safety levels within a location as well as across locations. Several evaluation examples are presented to illustrate how the method can be used and how the estimation results can be interpreted.
Crash Estimation at Signalized Intersections along Corridors
Authors: Abdel-Aty Mohamed , Wang Xuesong
Published: May 2018

Intersections could be considered as isolated when the distance between them is long because, the influence between them is negligible. Signalized intersections, especially closer ones along a certain corridor, are spatially correlated and will influence each other in many respects. Use of the basic negative binomial regression for correlated crash frequency data leads to invalid statistical inference due to incorrect test statistics and standard errors that are based on the misspecified variance. Generalized estimating equations (GEE) provide an extension of generalized linear models to the analysis of correlated data and can account for the spatial correlation among signalized intersections. In this study, 476 signalized intersections from 41 corridors are selected in Orange, Brevard, and Miami–Dade Counties in Florida. Because the distance between some intersections along some corridors is very long, the intersections along the 41 corridors were divided into 116 clusters. The spatially correlated crash frequency data were fitted through use of GEE models with a negative binomial link function for three correlation structures. Subsequent relative effect analysis identified the relative significance for the variables in the models. Intersections with a large total number of lanes, heavy traffic, short signal spacing, high speed limits along corridors, and a large number of phases per cycle were correlated with high crash frequencies. Intersections having three legs, with exclusive right-turn lanes on both roadways, having a protected phase for left-turning traffic from a corridor, and located in open county or primarily residential areas had lower crash frequencies.
Development of New Crash Experience Warrants for Traffic Signals in Ontario, Canada
Authors: Hadayeghi Alireza , Malone Brian , De Gannes Roger
Published: May 2018

Traffic signals, if properly designed and justified according to current engineering practice, can improve the traffic safety and traffic operations at intersections. The effects of resulting crashes and the impacts on safety from the installation of traffic signals at unsignalized intersections are complicated, and the current literature and research on this topic are limited, even though traffic signals have been used for many years. The current crash warrants in the Ontario Traffic Manual, Book 12: Traffic Signals do not take into consideration the effect of traffic volume variations in crashes. It states that if conditions such as “five or more ‘correctable’ crashes per 12 month period averaged over a 36 month period” are satisfied, a signal may be warranted. The purpose of this paper is to develop and recommend a safety analysis and evaluation tool for estimating the expected safety of the installation of traffic signals through use of historical crash and volume data. The paper also provides a quantitative process tool for determining whether a traffic signal is justified at an unsignalized intersection. The proposed approach uses the empirical Bayes method and crash prediction models for estimating the safety effects on unsignalized intersections that are being considered for traffic signal installation. The performance of the proposed procedure is evaluated and analyzed on 17 unsignalized intersections taken from different jurisdictions in the province of Ontario, Canada.
Identifying Intersections with Potential for Red Light–Related Safety Improvement
Authors: Bonneson James A. , Zimmerman Karl
Published: May 2018

The problem of red light running is widespread and growing; its cost to society is significant. However, the literature is void of quantitative guidelines that can be used to identify and treat problem locations. Moreover, there has been concern voiced over the validity of various methods used to identify problem locations, especially when automated enforcement is being considered. This paper documents the development of a procedure for identifying and ranking intersection approaches with the potential for improvement in the area of crashes related to red lights. One component of this procedure is a safety prediction model. A sensitivity analysis of this model indicates that red light–related crashes decrease with an increase in duration of the yellow interval and a reduction in the speed limit.
Safety Effect of Continuous Shoulder Rumble Strips on Rural Interstates in Maine
Authors: Gårder Per , Davies Michael
Published: May 2018

In Maine, the first rumble strips were installed in 1994, and the Maine Department of Transportation and the Maine Turnpike Authority have now installed continuous shoulder rumble strips (CSRS) on the majority of the rural sections of the Interstate and turnpike system. There were approximately 620 freeway miles with CSRS at the end of 2004. The purpose of this study is to report on the effectiveness of these installations in preventing run-off-road (ROR) crashes. An evaluation of their effectiveness showed that CSRS reduced sleep-related ROR crashes by approximately 58%. A statistical analysis showed that there is 99.9% certainty that the typical reduction in sleep-related ROR crashes was at least 41%. Fatal crashes were reduced to a higher degree than other crashes. Dry road ROR crashes were reduced by about 43% making the cost–benefit ratio of installing CSRS on a typical Maine section at least 195. CSRS were less effective in eliminating crashes during inclement weather conditions. The overall effectiveness of CSRS installations was estimated to be a 27% reduction with respect to all ROR crashes.
Case Study Assessment of Crash Data Challenges
Authors: Benavente Marta , Knodler Michael A. , Rothenberg Heather
Published: May 2018

Data from crash reports do not generally include sufficient injury information for analysis of particulars of injuries resulting from crashes. In the Massachusetts Crash Data System, the primary field that relates to injury status is based on a well-known police-reported scale. More specific data on injuries and their associated hospital charges can be obtained with crash data from police reports at the crash scene being complemented with injury data from the medical care system. A database that includes information about the crash and specifics about the injuries will allow for the identification of possible injury patterns associated with particular crashes and their associated hospital charges. However, the lack of unique identifiers to link records in the different databases as well as data quality issues, such as misreporting and missing values, make challenging the process of combining these two databases and analyzing the data. This paper focuses on the challenges in the process of linking, through use of the Massachusetts Crash Outcome Data Evaluation System, crash records to inpatient hospital records. The paper illustrates the findings through a particular application analyzing crash compatibility issues. A mismatch crash occurs when a large vehicle collides with a smaller one, and size and weight incompatibilities could make the passengers traveling in the small vehicle more vulnerable to severe injury. Probabilistic linkage and multiple imputation were used to complete the linkage of 12 months of crash data to hospital inpatient discharge data.
Safety Evaluation of Stop Sign In-Fill Program
Authors: Sayed Tarek , El-Basyouny Karim , Pump John
Published: May 2018

This paper describes a project undertaken to evaluate the safety impacts associated with the Stop Sign In-Fill (SSIF) program. The SSIF program was launched by the Insurance Corporation of British Columbia (Canada) in 1998 and consists of installing stop signs alternately at every second intersection in residential neighborhoods in the Greater Vancouver Regional District. The main objective of the program is to reduce the frequency and severity of collisions and thereby reduce insurance claims costs in addition to providing a traffic-calming effect on residential neighborhoods. The evaluation included a time series analysis to investigate the effectiveness of the SSIF program on road safety performance at 380 intersections. The evaluation used comparison groups and three techniques to determine the safety impacts of the SSIF program. The first two techniques are based on the odds ratio methodology, while the third is based on the likelihood method. The results of the three techniques were consistent and showed that injury collisions were reduced 61% to 72%, while total collisions were reduced 45% to 55%. It was concluded that the installation of stop signs at uncontrolled intersections in residential neighborhoods was an effective measure for reducing both the frequency and severity of collisions in urban areas.
Motorized Two-Wheeled Vehicle Emissions in India
Authors: Badami Madhav G. , Iyer Narayan V.
Published: May 2018

Motor vehicle activity is growing rapidly in Indian cities, as in other Asian cities, with serious impacts, including deteriorating urban air quality. Motorized two-wheeled (M2W) vehicles, which provide affordable mobility to millions, form the bulk of the motor vehicle fleet and contribute significantly to transport emissions. Vehicle and fuel technologies are important and have been vastly improved since the 1990s. However, on the basis of an in-depth survey of vehicle users and an analysis of emerging trends in consumer preferences, policies, and industry plans, this paper demonstrates various important ways in which user preferences and choices relating to vehicle purchase, operation, and maintenance, interacting with institutional and technological factors, contribute to emissions and affect policy implementation, particularly with reference to M2W vehicles in India. The paper highlights the importance of considering the interaction of these factors, and how users and other actors are affected by and respond to policies, in more effectively addressing emissions from M2W vehicles and other vehicles, especially given in-use realities and constraints.
Regulation of Motorized Two-Wheelers in India
Authors: Agarwal Om Prakash
Published: May 2018

Since the mid-1980s, India has witnessed a rapid growth in the number of motor vehicles, driven primarily by the demand for motorized two-wheelers (M2Ws). These vehicles have served a very useful purpose, especially for the lower middle class, in offering easy and flexible mobility at costs that are much lower than those of a car. However, their affordability and extensive use have imposed high social costs in terms of air pollution, high accident fatality rates, and possibly road congestion. Therefore, there is a case for public regulation of M2Ws. This paper looks at the regulatory systems and practices currently in place, with a view to identifying gaps. It finds that fragmented policy making and uncoordinated regulatory efforts spanning multiple agencies and jurisdictions are serious gaps that must be filled. It concludes that reforms in the current systems of governance that devolve greater authority to the city level, qualitative improvements in the public transport system, and legal provisions that specifically address the needs of urban areas would be appropriate strategies to adopt.
Feedback Approach for Determining Parameters of Vehicle Safety Regulation on Pedestrian Protection
Authors: Oh Cheol , Kang Youn-soo , Chang Myung-soon
Published: May 2018

In recent years, significant efforts have been made around the world to establish an internationally agreed-upon vehicle safety regulation that will reduce pedestrian casualties in pedestrian–vehicle collisions. One of the key issues in putting together the regulation is how to select effectively the parameter values that will be associated with it. This study develops an integrated feedback-based decision-making procedure for determining parameter values of the vehicle safety regulation. The regulation aims to protect pedestrian heads in pedestrian–vehicle collisions. Detailed data analyses from both actual accidents and simulations were conducted to derive parameters that result in technically and economically feasible regulation. A set of parameters representing the characteristics of pedestrian accidents and vehicles in South Korea is presented as the outcome of this study. The major contribution of this study is in supporting the establishment of South Korean vehicle safety regulations that would lead to the development of advanced vehicular technologies to reduce the severity of pedestrian injuries.
Bicycle-Based Courier and Delivery Services in Beijing
Authors: Hong Zhao , Zhiliang Wei , Wei Li
Published: May 2018

Based on a large sample survey conducted in 2004, this paper presents a market analysis of the bicycle delivery service systems in Beijing. The discussion includes distribution companies, distribution services, employment, employees, and customers. In addition to the sample survey, on-the-spot visits and additional analyses were carried out. Future trends in bicycle delivery service systems in Beijing are also presented. Based on a strengths, weaknesses, opportunities, and threats (SWOT) model analysis, the paper also forecasts and suggests methods for repositioning bicycle delivery service systems in Chinese cities. The suggestions are China-specific and are meant to assist the regulatory authorities in the supervision of the transport logistics system and the standardization of delivery service by means of bicycle.
Increasing Schedule Reliability on the S-Bahn in Zurich, Switzerland
Authors: Nash Andrew , Weidmann Ulrich , Bollinger Stephan , Luethi Marco , Buchmueller Stefan
Published: May 2018

Delays on the regional rail system in Zurich, Switzerland, had risen to unacceptable levels by 2003 because of increasing ridership and more frequent service. The research goal was to identify the causes of delay, develop measures to reduce delays, evaluate these measures, and make recommendations. A combination of engineering and computerized statistical analysis was used to identify and evaluate delays. The main causes of delay were increased station dwell time (for passenger boarding and alighting), trains entering the core network late, and suboptimal track and platform dispatching. Measures for reducing delays were developed and tested by simulation. Recommended measures included systematic revision of dwell times throughout the network, new stopping patterns, new dispatching techniques, and development of a prioritized infrastructure program. Several recommendations were implemented in the December 2004 schedule change and have helped reduce delay. The study's main recommendation is that the identified measures be implemented systematically and continuously.
Selecting Indicators for Strategic Performance Management
Authors: Marsden Greg , Kelly Charlotte , Snell Carolyn
Published: May 2018

There is a growing emphasis on the use of indicators for performance measurement and management in the transport sector. In the United Kingdom all local authorities are now required to set out 5-year programs with commitments on progress over a range of mandatory and voluntary indicators linked to a series of key policy outcomes. Increasingly, the financial settlements that local authorities receive from the central government will be related to their performance against these targets. Different types of information are needed to fulfill different roles in the decision-making process. Research in the United Kingdom has indicated that there are too many indicators and yet too little clarity about what is being collected and reported on, at what level, and why. This paper reports on a study examining the use of indicators in 16 local and regional authorities in the United Kingdom. The results from a questionnaire and a series of follow-up interviews are combined with the findings of a desktop review of performance management in the public sector to propose a more logical and connected process for developing a suite of indicators that supports both strategy development and monitoring. The results suggest that the current indicator sets are not broad enough to ensure that the strategies proposed are consistent with sustainable transport goals. The lack of a comprehensive framework also increases the risk of negative impacts from monitoring programs, such as measure fixation and myopia. The more comprehensive approach proposed seeks to bring together the aspirations of strategy with the realities of measurement.
The World can be Flat
Authors: Ungemah David , Rivers Malaika , Anderson Stuart
Published: May 2018

Many metropolitan areas have experimented with fare pricing to encourage greater use and participation in vanpools. To increase significantly the rate of participation in vanpools, one transportation management association (TMA) in the Atlanta, Georgia, area implemented a flat-rate pricing program to provide a simplified and tangible subsidy to potential riders and to encourage employer participation in vanpooling. This paper provides a case study of this flat-rate pricing program for the Cumberland Community Improvement District. The case study shows significant increases, greatly exceeding the initial forecasts, in the rates of vanpool utilization and participation. However, certain issues remain for other communities looking to replicate TMA's program.
Six Principles of Persuasion to Promote Community-Based Travel Behavior Change
Authors: Seethaler Rita K. , Rose Geoff
Published: May 2018

Social psychology offers a series of persuasion techniques that are able to strengthen the impact of travel demand management programs. This is particularly the case for community-based programs of voluntary travel behavior change such as the TravelSmart programs currently being conducted in Melbourne, Australia. This paper presents the results of an experiment that has applied six particular persuasion techniques as part of a community-based TravelSmart campaign. In a pilot test of 160 households, combinations of persuasion elements were tested with eight different treatment groups while a number of sociodemographic variables were controlled. Although the results were not statistically significant at the 95% confidence level because of a limited sample size, the results indicated an increase in the rate of participation when persuasion strategies were integrated into the TravelSmart recruitment process. Modeling of the intervention uptake as a function of sociodemographic variables indicated the problem of linguistic barriers in association with a multicultural urban population. In contrast, bicycle availability and the current use of public transit both had positive impacts on TravelSmart participation. Initial analysis of the results from a larger field test of some 800 test and control households reinforced the positive impact of the persuasion strategies. Overall, the results indicate the need to explore an extension of the persuasion principles from their use in the recruitment process to all other implementation stages of voluntary travel behavior change programs.
Evaluation of Sidewalk Unevenness Based on Wheelchair Traveling Resistance
Authors: Ishida Tateki , Takemoto Hideto , Ishida Shinji , Kameyama Shuichi , Himeno Kenji , Kashima Shigeru
Published: May 2018

Differences in the levels and the transverse and longitudinal gradients on sidewalks can seriously hinder the mobility of wheelchair users. On sidewalks where such differences and gradients are minor, the mobility of wheelchair users can be seriously hindered by surface unevenness in the case of rough sidewalks. This paper analyzes the longitudinal profiles of sidewalks in service and torque data for traveling wheelchairs with the goal of proposing a method for evaluating the surface unevenness of sidewalks based on the travel resistance imposed on wheelchairs. A test track with variable gradients and unevenness was traveled by panel members, who were then asked to rate the subjective discomfort of the test track. The study revealed a strong correlation between the surface unevenness values calculated by the proposed method and the discomfort rating offered by the panel members.
Access and Mobility Design Policy for Disabled Pedestrians at Road Crossings
Authors: Schoon John G. , Hounsell Nick B.
Published: May 2018

Issues affecting design policies for highways and streets are explored in terms of the functional capabilities of disabled and encumbered pedestrians. The analysis and design process for disabled and encumbered people is explored to complement the emphasis accorded driver and vehicle movements in current codes and design policies. Issues related to the integration of code requirements and documented design procedures with the physical capabilities of disabled people in relation to existing policies are examined. Considerations include the location of the visibility viewpoint, associated sight lines, the observation–reaction time immediately before crossing, the distance traveled across footways, and movement characteristics while traversing the carriageway and while completing the crossing. The data described include experimental movement observations obtained by video and documented values. The links with physical disability categories are briefly described. A numerical illustration of the total time required to cross is made. The major issues are summarized, and an outline of areas needing further investigation is presented.
Gender Dimensions of Transport in Developing Countries
Authors: Riverson John , Kunieda Mika , Roberts Peter , Lewi Negede , Walker Wendy M.
Published: May 2018

Women in most developing countries have limited access to transport services and technology. This lack of transport imposes severe constraints on their access to health, education, and other social facilities and services, making them and their children more vulnerable to serious injury or death as a result of childbirth or another medical emergency. Understanding and responding to women's transport needs are essential for reducing poverty, as reflected in the United Nations statement of the Millennium Development Goals. Many governments and development agencies have learned much from extensive field research and case studies about women's and men's substantially different patterns of mobility needs. In recent years, the World Bank has integrated these gender concerns and needs into its policies and has encouraged borrowing countries to address the concerns of women in their national, regional, and local projects and programs. The World Bank has developed corresponding guidance for the transport sector and encourages its application as appropriate in all the transport investments that it supports. This paper summarizes examples of good practice and illustrates its application in Ethiopia. However, the World Bank's Transport Sector is concerned that the outcomes for women of the interventions that it supports often continue to fall short of expectations. This paper describes the steps that are being taken to improve the effective meeting of gender needs. The paper also highlights the value of participating in a broad network of development specialist groups to share experience of effective good practices and to strengthen the scope for matching specific cultural and institutional conditions.