Determining the drivers’ acceptance of EFTCD in highway work zones

Traffic safety is a major concern in the temporary one-lane, two-way highway work zones due to the increasing of construction and maintenance operations. To prevent rear-end crashes and to mitigate the severity of these crashes caused by the inattentive driving, the utilization of the Emergency Flasher Traffic Control Device (EFTCD) was under consideration by government agencies, in addition to existing temporary traffic control devices installed in the one-lane, two-way highway work zones. The EFTCD was a newly proposed traffic warning device implemented through the use of vehicles’ hazard warning flashers. The primary objective of the research project was to investigate the drivers’ acceptance of the proposed EFTCD by measuring the mean speed changes of vehicles with and without EFTCD and by evaluating the drivers’ opinions of the EFTCD using the survey method. Field experimental results revealed that the EFTCD effectively reduced the mean vehicle speeds in the upstream of two work zones. A slow speed is more likely to reduce the severity of a crash in work zones. In addition, survey results indicated that 60% of the drivers thought the EFTCD signified a need for speed reduction and 82% of drivers recommended the implementation of the EFTCD in one-lane, two-way work zones. These results provide the necessary scientific justifications for the government agencies to decide if the EFTCD should be implemented in the one-lane, two-way highway work zones to prevent rear-end crashes and to mitigate the severity of these crashes

Highway Work Zone Risk Factors and Their Impact on Crash Severity

Numerous factors may contribute to high-severity crashes in highway work zones. Identifying these factors and then alleviating their impact is a challenging task that traffic engineers and researchers have to confront. In this study, the work zone risk factors that could increase the probability of causing fatalities when severe crashes occur were examined using a comprehensive approach. The researchers first identified the significant risk factors based on a screening process that incorporates both statistical analyses and empirical research findings. They then systematically investigated these factors using logistic regression and frequency analysis techniques. The severe crashes including the fatal crashes between 1998 and 2004 and injury crashes between 2003 and 2004 in Kansas highway work zones were used in the study. The assessed risk factors included variables describing driver characteristics, environmental conditions, crash road conditions, and other crash information. The results of this study will help traffic engineers to understand these risk factors and how the factors could increase the likelihood of having fatalities when a severe crash occurs in a work zone. Consequently, effective safety countermeasures may be designed at the work zone planning and installation stages to prevent safety deficiencies

Effectiveness of Temporary Traffic Control Measures in Highway Work Zones

In the United States, hundreds of people lose their lives each year and many more are injured due to vehicle crashes in the work zones. Over the years, temporary traffic control (TCC) measures have been developed and deployed in work zones. To continuously improve the safety, there is a need to identify the traffic control deficiencies in work zones by evaluating the effectiveness of existing TTC measures based on the real crash cases. In this study, researchers evaluated the effectiveness of several commonly used TTC methods using logistic regression techniques and various significance test methods including likelihood ratio test, score test, and Wald test. These TTC methods included flagger/officer, stop sign/signal, flasher, no passing zone control, and pavement center/edge lines. A total of 655 severe crashes in Kansas highway work zones between January 2003 and December 2004 were used for the evaluation, which included 29 fatal crashes and 626 injury crashes. Results indicated that flagger, flasher, and pavement center/edge lines were effective in reducing the probability of causing fatalities when severe crashes occurred. In addition, using these devices could prevent some common human errors, such as “disregarded traffic control”, “inattentive driving”, “followed too closely”, and “exceeded speed limit or too fast for condition”, from causing severe crashes

Development of Crash-Severity-Index Models for the Measurement of Work Zone Risk Levels

Highway work zones interrupt regular traffic flows and create safety problems. Improving safety without sacrificing the main function of highways is a challenging task that traffic engineers and researchers have to confront. In this study, the concept of using crash severity index (CSI) for work zone safety evaluation was proposed and a set of CSI models were developed through the modeling of work zone crash severity outcomes. A CSI is a numerical value between zero and one that is estimated from given work zone variables. It is interpreted as the likelihood of having fatality/fatalities when a severe crash occurs in a given work zone. The CSI models were developed using a three-step approach. First, a wide range of crash variables were examined in a comprehensive manner and the significant risk factors that had impact on crash severity were selected. Second, the CSI models were developed using logistic regression technique by incorporating the selected risk factors. Finally, the developed models were validated using the recent crash data and their ability in assessing work zone risk levels were analyzed. Results of this study showed that CSI models can provide straightforward measurements of work zone risk levels

Effectiveness of temporary traffic control measures in highway work zones

In the United States, hundreds of people lose their lives each year and many more are injured due to vehicle crashes in the work zones. Over the years, temporary traffic control (TCC) measures have been developed and deployed in work zones. To continuously improve the safety, there is a need to identify the traffic control deficiencies in work zones by evaluating the effectiveness of existing TTC measures based on the real crash cases. In this study, researchers evaluated the effectiveness of several commonly used TTC methods using logistic regression techniques and various significance test methods including likelihood ratio test, score test, and Wald test. These TTC methods included flagger/officer, stop sign/signal, flasher, no passing zone control, and pavement center/edge lines. A total of 655 severe crashes in Kansas highway work zones between January 2003 and December 2004 were used for the evaluation, which included 29 fatal crashes and 626 injury crashes. Results indicated that flagger, flasher, and pavement center/edge lines were effective in reducing the probability of causing fatalities when severe crashes occurred. In addition, using these devices could prevent some common human errors, such as “disregarded traffic control”, “inattentive driving”, “followed too closely”, and “exceeded speed limit or too fast for condition”, from causing severe crashes

Determining Major Causes of Highway Work Zone Accidents in Kansas, Phase II

The work zones on the United States highway system have created an inevitable disruption on regular traffic flows and resulted in traffic safety problems. Understanding the characteristics and major causes of highway work zone crashes is a critical step towards developing effective safety countermeasures in highway work zones. In 2004, the Kansas Department of Transportation (KDOT) initiated a project (K-TRAN Project No. KU-05-01) to study the fatal crashes in Kansas highway work zones between 1992 and 2004. The study results including crash characteristics and major crash contributing factors were published in Bai and Li (2006). Built on the previous success, KDOT sponsored this research project (K-TRAN Project No. KU-06-01) to further study the injury crashes during the same period in Kansas highway work zones. The primary objectives of this study were to investigate the characteristics of the injury crashes, to identify risk factors that contributed to the injury crashes, and to compare characteristics between fatal and injury crashes in highway work zones. Frequency analysis was utilized to discover the basic characteristics reflected by single-variable frequencies as well as the complicated characteristics based on cross-categorized frequencies. The variable combinations used for analyzing cross-categorized frequencies were identified through independence test methods such as Pearson Chi-Square Test and Likelihood-Ratio Chi-Square Test. The characteristic comparison between fatal and injury crashes further helps to document the general characteristics of both fatal and injury crashes and to discover the unique factors that characterize different severities. The researchers found significant characteristics of Kansas highway work zone injury crashes and summarized them in six categories. The researchers also discovered noteworthy characteristic differences between work zone fatal and injury crashes and concluded the important factors that could have increased the severity of work zone crashes. Potential safety improvements were recommended accordingly and future research were suggested. The significant insights from this study are valuable for the design of safer highway work zones and for the development of safety countermeasures that have potential not only in reducing the number of crashes but also in mitigating the crash severity

Comparison of characteristics between fatal and injury accidents in the highway construction zones

Highway construction zone safety has been a research focus in many countries for many decades. In the United States, regardless of the research efforts devoted, highway construction zones remain a serious safety concern for government agencies, legislatures, the highway industry, and the traveling public. In this study, the fatal and injury accidents between 1992 and 2004 in Kansas highway construction zones were examined systematically and their major characteristics were compared. The results showed significant differences between fatal and injury accidents in the construction zones. The researchers found that: (1) head-on was the dominant type for fatal accidents while rear-end was the dominant injury accident type; (2) a large percent of fatal accidents involved trucks while a majority of injury accidents involved light-duty vehicles only; (3) disregarded traffic control, alcohol impairment, and speeding caused a much larger proportion of fatal accidents while followed too close caused a much higher percentage of injury accidents; and (4) unfavorable light conditions and complicated road geometries contributed to causing a larger percentage of fatal accidents than to causing injury accidents. Based on the study results, practical safety countermeasures targeted at different severity of accidents are recommended in terms of construction zone traffic control and public education

Reducing Work Zone Crashes By Using Vehicle's Warning Flashes As a Warning Sign

Rural two-lane highways constitute a large percentage of the highway system in Kansas. Preserving, expending, and enhancing these highways require the set-up of a large number of one-lane, two-way work zones where traffic safety has been a severe concern. Aimed at reducing the work zone crashes attributable to inattentive driving, the Kansas Department of Transportation (KDOT) initiated a research project to evaluate the effectiveness of a traffic warning sign that is assembled by using the emergency warning flashers of the vehicles in one-lane, two-way work zones. This warning sign was named as the Emergency Flasher Traffic Control Device (EFTCD). It works in the following fashion. When a vehicle entering a one-lane, two-way work zone where stopping is required for waiting to pass the work zone, the driver is required to turn on its emergency warning flashers to warn the following vehicles of the work zone stopping condition. The EFTCD is flexible and cost-effective and may particularly benefit those work zones that are frequently moved due to the construction progress. To accurately evaluate the effectiveness of the proposed EFTCD, researchers conducted experiments in three one-lane, two-way work zones in Kansas including two with a 55-mph speed limit and one with a 65-mph speed limit. During experimental period, researchers collected vehicle speed data with and without the EFTCD and surveyed drivers for their interpretation of this warning sign and recommendation on its potential implementation. Analyses results showed that the EFTCD effectively reduced the mean speeds in work zones as well as the proportions of notably high speeds. In addition, survey results indicated that the EFTCD successfully captured the attention of most drivers when they approached the work zones. A majority of drivers recommended the implementation of this warning sign in the work zones. Therefore, researchers concluded that the EFTCD was effective in one-lane, two-way work zones. Recommendations on future research were also presented based on the results of this study. The outcomes of this research project benefit not only Kansas, but also other States where rural two-lane highways constitute a high percentage of their highway systems

Comparison of Characteristics Between Fatal and Injury Accidents in the Highway Construction Zones

Highway construction zone safety has been a research focus in many countries for many decades. In the United States, regardless of the research efforts devoted, highway construction zones remain a serious safety concern for government agencies, legislatures, the highway industry, and the traveling public. In this study, the fatal and injury accidents between 1992 and 2004 in Kansas highway construction zones were examined systematically and their major characteristics were compared. The results showed significant differences between fatal and injury accidents in the construction zones. The researchers found that: (1) head-on was the dominant type for fatal accidents while rear-end was the dominant injury accident type; (2) a large percent of fatal accidents involved trucks while a majority of injury accidents involved light-duty vehicles only; (3) disregarded traffic control, alcohol impairment, and speeding caused a much larger proportion of fatal accidents while followed too close caused a much higher percentage of injury accidents; and (4) unfavorable light conditions and complicated road geometries contributed to causing a larger percentage of fatal accidents than to causing injury accidents. Based on the study results, practical safety countermeasures targeted at different severity of accidents are recommended in terms of construction zone traffic control and public education