Analysis of Accident Data and Evaluation of Leading Causes for Traffic Accidents in Jordan

Road safety is a primary concern and goal of highway and traffic engineers worldwide. The road network in Jordan exhibits relatively high traffic volumes, particularly in urban areas and in the Central Business District (CBD) areas of major cities. Jordan ranks one of the top countries worldwide in terms of having higher numbers of road traffic accidents leading to a relatively high number of fatalities and injuries. In the past few years in particular, the number of registered vehicles in Jordan has considerably increased. As a result, traffic volumes and Vehicle Miles of Travel (VMT) have significantly increased leading to deteriorating traffic flows and escalating traffic congestions and jams. Consequently, the number of road traffic accidents has also noticeably increased in Jordan in the past decade. Complete analysis of statistical data obtained for traffic accidents in Jordan was conducted in this study. Evaluation of the possible leading causes of traffic accidents in Jordan was also carried out. Different possible causes along with behaviors of drivers and pedestrians were investigated and correlated with the number of traffic accidents, fatalities and injuries. Jordan was found to have accident, fatality and injury rates that are considerably higher than those of other countries in the world. Nonetheless, as rates with time, the fatality and injury rates seemed to be moving in the right direction. Yet, the number of traffic accidents, fatalities and injuries looked critical. Traffic accidents and casualties were observed to be higher in summer times. More than 90 percent of traffic accidents, fatalities and injuries occurred on roads with speed limits between 40 and 60 km/h. Pedestrians composed the highest percentage of the total numbers of fatalities and injuries. The majority of driver casualties and passenger casualties (fatalities and injuries) belonged to the age group of 18-42 years. On the other hand, the highest percentage of pedestrian casualties belonged to the age group of 0-18 years. However, about 80 percent of the casualties in Jordan were males and only 20 percent were females. “Tailgating” and “not taking safety measurements during driving” were the most two important driver behaviors in terms of traffic accidents. Yet, behaviors of “using wrong lane” and “not taking safety measurements during driving” led to the highest percentages of the total number of fatalities and injuries. The majority of the pedestrian fatalities and injuries were in fact walking on road during the time of the accident occurrence and about one third of them were walking on sidewalk. Other behaviors of drivers and pedestrians were also important and created traffic complexity and hazardous situations leading to a reduction in saturation flow rates and in capacities and causing bottleneck conditions and traffic jams; hence resulting in traffic safety concerns

A Distinctive Fatigue Failure Criterion

Abstract This paper presents a new fatigue failure criterion for asphalt paving mixtures that is simple, unique, and distinctive. Bending beam fatigue testing in the controlled strain mode at a 1000-microstrain level and 19C temperature was performed on eleven asphalt mixtures that included unmodified and modified binders. Analysis of fatigue load-deformation raw data for each fatigue load cycle was conducted to determine the true point of fatigue failure. With application of a sinusoidal strain on a sample, a sinusoidal response stress is expected even for a heterogeneous material like asphalt concrete. In such a case, a smooth traditional load-deformation (or stress-strain) hysteresis loop is anticipated. This holds true as long as there is no fatigue damage induced in the material. With repeated load applications, the sample starts to fatigue and microcracks are induced. These microcracks introduce discontinuities in the stress paths and the stress response starts to distort. This gets reflected in the load-deformation hysteresis loop, which in turn shows this distortion. Similar distortion can also be seen by observing the sinusoidal load-deformation waveform, where the stress response is no longer dependent on the strain input due to the formation of interconnected fatigue cracks. By tracking the distortion in the hysteresis loop or in the waveform, one is able to get a clear indication of when the first microcracks appeared, and how they progressed up to the point of complete fatigue failure

Fatigue Performance: Asphalt Binder versus Mixture versus Full-Scale Pavements

The Federal Highway Administration (FHWA) built 12 asphalt pavements in 1993 to validate Superpave tests and specifications used to measure the rutting and fatigue cracking performances of hot-mix asphalts and asphalt binders. Each pavement had four test sites. These sites were tested for either rutting or fatigue cracking using the FHWA’s Accelerated Loading Facility (ALF). The main objective of the study documented in this paper was to compare the fatigue performance results from laboratory bending beam fatigue tests to the ALF fatigue cracking data obtained for these sites from lanes 1 through 4. The four lanes consisted of two asphalt pavement layer thicknesses (100 and 200 mm) and two asphalt binders (PG 58-34 and PG 64-22). Each lane was tested at three temperatures 10, 19, and 28°C. Another objective of this study was to investigate the relationship between the asphalt binder parameter for intermediate temperature performance (G*sinδ) and asphalt pavement fatigue life. Findings of this study showed that a relatively good correlation was obtained between the ALF pavement fatigue life and the asphalt mixture fatigue life from the strain-controlled bending beam fatigue tests. Comparison of the fatigue results at the three test temperatures showed rational trends with the longest fatigue life at 28°C and the shortest fatigue life at 10°C. Fatigue power models at these test temperatures were also obtained for asphalt mixtures produced using the two asphalt binders

Evaluation of 2008 Traffic Safety Policies in Jordan

The problem of traffic accidents is a major problem in the Hashemite Kingdom of Jordan and represents a serious safety and economic challenge for the state. Traffic accidents are considered the second leading cause of death. This paper evaluated the impacts of the traffic policies undertaken in 2008 on traffic accidents and fatalities, including the intensification of police enforcement and implementation of traffic law with stiff penalty levels. To accomplish this objective, accidents’ data of 1990 through 2009 were obtained from Jordan Traffic Institute and other related sources. Results of analysis revealed that Jordan has experienced huge human and economic losses as well as social and emotional negative impacts. Furthermore, the safety policy measures undertaken in 2008, including the intensification of police enforcement and the increase of penalties for excessive speed had an overall positive influence in reducing accidents and fatalities. However, the application of 2007 traffic policy with stiffer penalties was the most effective measure. Finally, it is highly recommended to reapply 2007 traffic law with stiffer penalties since it contributed in reducing accidents and fatalities more than 2008 traffic law. In addition, it is recommended to apply all the needed safety polices to reduce the traffic accidents phenomenon in Jordan

Framework for Level-I Alligator Cracking Methodology for Use in the Mechanistic-Empirical (M-E) Pavement Design Guide.

The recently published Mechanistic-Empirical Pavement Design Guide (MEPDG) includes a global flexure fatigue model that can be used for Level 3 material input. This paper develops a typical framework for highway agencies to follow to calibrate their laboratory results and determine Level 1 flexure fatigue input for use in the design guide. An extensive flexure fatigue testing program was carried out on six hot-mix asphalt (HMA) materials typically used by the Arizona Department of Transportation. General fatigue models are developed using both constant strain and constant stress modes of loading. The general fatigue lab models were then calibrated to the global fatigue model in the MEPDG to be used as an input to Level 1 design. Shift factors were developed for each mix used and for different thicknesses of asphalt layers. The shift factor decreased from 20 at a 1-in. layer to 9 at a 4-in. layer, after which it remained constant. The procedure used in this paper serves as a guide for other agencies to follow to obtain Level 1 fatigue data input for the M-E Pavement Design Guide

Development of a Hollow-Cylinder Tensile Tester to Obtain Fundamental Mechanical Properties of Asphalt Paving Mixtures

259 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 2001.The HCT device was found to be both accurate and repeatable. The coefficient of variation was measured for the HCT and IDT tensile strength results. In general, the coefficient of variation of the HCT strengths was found to be lower than that of the IDT strengths, particularly for ultimate tensile strengths. The HCT and IDT were found to compare favorably in the determination of creep compliance at higher loading times, and first-failure strength. Thus a fundamental, test-independent strength property can be obtained with either device. On the other hand, ultimate tensile strength was found to be test mode and mixture-dependent. In general, ultimate tensile strengths were considerably higher in the HCT than the IDT, particularly for polymer-modified mixtures. The HCT ultimate strength was found to be strongly correlated to modification level, as opposed to the IDT ultimate strength, which was very weakly correlated to modification level.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Machine Learning Modeling of Wheel and Non-Wheel Path Longitudinal Cracking

Roads degrade over time due to various factors such as traffic loads, environmental conditions, and the quality of materials used. Significant investments have been poured into road construction globally, necessitating regular evaluations and the implementation of maintenance and rehabilitation (M&R) strategies to keep the infrastructure performing at a satisfactory level. The development and refinement of performance prediction models are essential for forecasting the condition of pavements, especially to address longitudinal cracking distress, a major issue in thick asphalt pavements. This research leverages multiple machine learning methods to create models predicting non-wheel path (NWP) and wheel path (WP) longitudinal cracking using data from the Long-Term Pavement Performance (LTPP) program. This study highlights the marked differences in distress conditions between WP and NWP, underscoring the importance of precise models that cater to their unique features. Aging trends for both types of cracking were identified through correlation analysis, showing an increase in WP cracking with age and a higher initial International Roughness Index (IRI) linked to NWP cracking. Factors such as material characteristics, kinematic viscosity, pavement thickness, air voids, particle size distribution, temperature, KESAL, and asphalt properties were found to significantly influence both WP and NWP cracking. The Exponential Gaussian Process Regression (GPR) emerged as the best model for NWP cracking, showcasing exceptional accuracy with the lowest RMSE of 89.11, MSE of 7940.72, and an impressive R-Squared of 0.63. For WP cracking, the Squared Exponential GPR model was most effective, with the lowest RMSE of 12.00, MSE of 143.93, and a high R-Squared of 0.62. The GPR models, with specific kernels for each cracking type, proved their adaptability and efficiency in various pavement scenarios. A comparative analysis highlighted the superiority of our new machine learning model, which achieved an R2 of 0.767, outperforming previous empirical models, demonstrating the strength and precision of our machine learning approach in predicting longitudinal cracking