Treatments for Crashes on Rural Two-Lane Highways in Texas

2000

Two-lane rural roads in Kentucky have the highest fatal crash rate of any type of highway in Kentucky. This report is the first phase of a study with the objectives of (1) identifying safety problems related to crashes on two-lane rural roads, (2) identifying high-crash locations, and (3) recommending possible improvements. The procedure used in this phase of the study involved an analysis of crash data to identify characteristics of crashes on two-lane rural roads, use of crash data to identify one-mile sections having critical crash rates, and a review of countermeasures to start development of recommendations to reduced crashes on this type of highway.

Transportation Research Record, 1989

Data on accidents, road characteristics, and traffic for rural, two-lane roads in seven states have been assembled. It was found that, for the same amount of traffic, different states record widely discrepant numbers of accidents. The discrepancy does not disappear even when roads with the same lane width, shoulder type, and terrain are examined. It is concluded that (a) data from different states should not be pooled, (b) warrants and standards based on accidents should be tailored to each state, and (c) the cause of the noted differences should be investigated.

This report presents the details of an investigation aimed at finding potential countermeasures to enhance safety of rural highways by identifying critical factors contributing towards higher severity of crashes. Crash data from KARS (Kansas Accident Reporting System) database was analyzed and crash severity was modeled using several statistical modeling approaches. These approaches comprised of ordered choice (ordered probit and ordered logit) and loglinear models.

Journal of Traffic and Transportation Engineering, Elsevier, 2017

In 2014, 32,675 deaths were recorded in vehicle crashes within the United States. Out of these, 51% of the fatalities occurred in rural highways compared to 49% in urban highways. No specific crash data are available for the built-up areas along rural highways. Due to high fatalities in rural highways, it is important to identify the factors that cause the vehicle crashes. The main objective of this study is to determine the factors associated with severities of crashes that occurred in built-up areas along the rural highways of Nevada. Those factors could aid in making informed decisions while setting up speed zones in these built-up areas. Using descriptive statistics and binary logistic regression model, 337 crashes that occurred in 11 towns along the rural highways from 2002 to 2010 were analyzed. The results showed that more crashes occurred during favorable driving conditions, e.g., 87% crashes on dry roads and 70% crashes in clear weather. The binary logistic regression model showed that crashes occurred from midnight until 4 a.m. were 58.3% likely to be injury crashes rather than property damage only crashes, when other factors were kept at their mean values. Crashes on weekdays were three times more likely to be injury crashes than that occurred on weekends. When other factors were kept at their mean value, crashes involving motorcycles had an 80.2% probability of being injury crashes. Speeding was found to be 17 times more responsible for injury crashes than mechanical defects of the vehicle. As a result of this study, the Nevada Department of Transportation now can take various steps to improve public safety, including steps to reduce speeding and encourage the use of helmets for motorcycle riders.

International Journal of Injury Control and Safety Promotion, 2019

This study identifies and compares those risk factors affecting crash injuries and fatalities on rural freeways in Montana and West Virginia in the United States using the mixed logit model. Three-year crashes on rural freeway segments in both states are used. Higher annual average daily traffic (AADT) was associated with a reduction in injuries/fatalities in both states, with higher reduction in West Virginia (40%) than in Montana (25%). In both states, the impact of adverse road surface conditions (i.e., snowy/icy) was associated with a reduction in injuries/fatalities. The results show that separate injury severity models for individual states are suggested instead of lumping all crashes in one model. Enforcement of trucks' risky maneuvers (e.g., illegal traveling in the leftmost lane) and more education for older drivers are suggested in West Virginia. In Montana, it is recommended to monitor rural freeway segments with high sport utility vehicle (SUV) crash history.

2006

The study investigated the safety effects of geometric and other roadway characteristics of rural two-lane roads by collecting and analyzing data and developing crash prediction models, crash reduction factors (CRFs), and cost-effectiveness ratios (CERs). On the basis of these results, and the existing inventory of roads and their geometric deficiencies, physical and monetary needs assessments were carried out under alternative budgeting and crash costing scenarios for the rural two-lane state highway network. It was found that influential crash factors at such roads include section length, traffic volume, lane width, shoulder width, pavement condition, average horizontal curve radius, and grades of vertical slopes. For county roads, additional influential variables are shoulder type, driveway density, and the presence of speed limit posting. The percentage reduction in crashes due to the various safety countermeasures was found to vary by crash severity type, highway class, level of deficiency, and the extent to which the deficiency is addressed. CRFs were developed for lane and shoulder widening, minor realignment and earthworks that increase horizontal curve radius or to decrease in vertical curve slope, pavement friction enhancement (for rural major collectors and minor arterials) and pavement condition improvement (for rural principal arterials). CERs were developed for each countermeasure, crash type and road functional class. CERs are useful for safety project evaluation particularly when INDOT/LTAP seeks to compare the safety benefit per dollar across mutually exclusive safety countermeasures at a specific problem area, or when a specific area suffers from multiple safety problem types and can therefore receive many different countermeasures only a few of which can be funded. For rural two-lane state highway sections that are deficient-but-not-necessarily-hazardous and both-hazardous-and-deficient sections, it was found that $530 million and $55 million, respectively, would be needed to address the engineering safety needs. Given an annual expenditure of $1M over a 5-year period, approximately 170 crashes (translating to $8-15 million, depending on crash costing method) could be saved. If the annual expenditure is increased to $2M over the same period, approximately 240 crashes (translating to $12-26 million) could be saved. The study results also suggest that there seems to exist a ceiling of effectiveness for engineering safety countermeasures, and therefore non-engineering countermeasures such as safety education and enforcement are also vital to further reduce crashes related to drivers, vehicles, and the driving environment. Implementation of the study would involve application of the study products for safety management at both state and local levels to make cost-effective decisions that will reduce highway crashes and thereby accrue the secondary and indirect benefits of increased mobility, enhanced geriatric driving, reduced tort liability, and enhanced economic productivity.

Journal of Modern Transportation, 2014

This paper presents a current investigation into crash experience along a 15.7-mile rural corridor in southwest Montana with the aim of better understanding crash causal factors along the corridor. The study utilized ten years of crash data, geometric data, and observed freeflow speed data along the corridor. A systematic approach was used where every tenth of a mile was described in term of the crash experience, speed, alignment, and roadside features. Using bivariate and multivariate statistical analyses, the study investigated the crash experience along the corridor as well as some of the underlying relationships which could explain some of the crash causal factors. Results show a strong association between crash rates and horizontal curvatures even for flat curves that can be negotiated at speeds above the posted speed limit, per the highway design equations. Higher crash rates were also found to be associated with the difference between the observed free-flow speeds and the speed dictated by the curve radius or sight distance as per the design equations. Further, results strongly support the safety benefits of guardrails as evidenced by the lower crash rates and severities. The presence of fixed objects and the steepness of side slopes were also found to have an effect on crash rates and severities.

Journal of Society for Transportation and Traffic Studies, 2014

A Run-Off-Road (ROR) crash occurs when a vehicle leaves the travel lane resulting in a collision. ROR crashes have become a major cause of serious injuries and fatalities in the United States. Data from Kansas Crash and Analysis Reporting System database during the period 2007 to 2011 were used in this study to examine ROR crashes. Identification of various characteristics related to environment, roadway, driver, and vehicle as well as factors contributing to rural ROR and urban ROR crashes is important because potential countermeasures can be developed to improve roadside safety. It was found that avoidance/evasive actions; driver being ill, falling asleep or fatigued; or animal at the road are more common on rural roadways than urban roadways, leading to ROR crashes.

This second in a series of CERS research reports summarizes the characteristics of the fatal rural roadway crashes within five Minnesota counties and describes some of the safety improvement programs or campaigns being used in this five-county area. Past research has shown that some of the many characteristics of fatal rural roadway crashes include younger drivers, alcohol involvement, lack of seat belt use, and speeding. The crash data summarized in this report were generally obtained from the