Browsing by Author "Hossain, Fahmid"

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Economic feasibility of safety improvements on low-volume roads
(2017-09) Al-Kaisy, Ahmed; Ewan, Levi A.; Hossain, Fahmid
This article presents an investigation into the economic feasibility of safety countermeasures along rural low-volume roads. Although these roads may be associated with higher crash risks as they\'re built to meet lower standards, crash frequencies are notably lower than those on other roadways with higher traffic exposure. Therefore, it is reasonable to expect that some conventional safety countermeasures that are proven to be cost effective on well-travelled roads may turn out to be infeasible on low-volume roads. Twenty-seven safety improvements were examined in this investigation for their economic feasibility along low-volume roads. A roadway sample of 681 miles of Oregon was used in this study. Detailed benefit-cost analyses were performed using countermeasure costs, 10-year crash data, and expected crash reductions using Highway Safety Manual methods. Around half of the countermeasures investigated were found cost-effective for implementation along low-volume roads. Further, most of the countermeasures that were found to have very high benefit-cost ratio are associated with low initial cost and many of them do not require much maintenance cost. At the other end of the spectrum, almost all roadway cross-section safety improvements were found economically infeasible due to higher associated costs relative to the expected crash reduction benefits on low volume roads.
Risk factors associated with high potential for crashes on low-volume roads
(Montana State University - Bozeman, College of Engineering, 2016) Hossain, Fahmid; Chairperson, Graduate Committee: Ahmed Al-Kaisy
A significant portion of the roadway mileage in the U.S. is comprised of the low volume roads. As these roads experience very low crash frequencies, the identification of hazardous locations based on crash history alone is difficult. However, these low-volume roads may be associated with higher level of risks and consequently higher crash rates due to substandard geometry on these roads. Therefore, an approach to identify hazardous locations on low volume roads which accounts for geometric and roadside features as well as crash history seemed to be necessary. For this purpose, roadway data from Oregon's low volume roads and 10-years of crash data on the selected sample were collected and analyzed to identify the roadway geometric and roadside features that contribute to the crash occurrence. Length of the horizontal and vertical curves under 100 feet, degree of curvature over 30 degrees, vertical grade over 5 percent, lane width narrower than 11 feet, shoulder width of 0 feet, and driveway density of 5 driveways/mile were found as the most restrictive features contributing to higher crash rate. Based on these analyses a quantitative tool was developed for assessing the level of risk on low volume roads. The developed risk index, which is a function of roadway geometry, roadside features, traffic exposure, and crash history, is proactive in nature, as it does not rely heavily on crash occurrence in assessing crash risks. Application of the crash risk index on the three corridors of Oregon showed that, the use of risk index provides new information about the level of hazard along highway segments compared to using crash history alone. Economic feasibility of some potential low-cost safety countermeasures was analyzed to identify which countermeasures would ensure the maximum return on investments. Installation of the rumble strips, object markers, safety edge, centerline and edge-line markings were found to be most cost effective with benefit/cost ratio over 8. The same procedure can be followed by other states, with similar road and traffic conditions, to identify the contributing factors of crashes and identify the most-effective countermeasures to improve the safety of the road.
Safety Effects of Road Geometry and Roadside Features on Low-Volume Roads in Oregon
(2016-01) Ewan, Levi A.; Al-Kaisy, Ahmed; Hossain, Fahmid
Crashes are random events and can occur at any location along a roadway. On roadways with high traffic volumes, the more frequent occurrence of crashes permits the direct identification of high-frequency crash locations with the use of historical data. On low-volume roads, crash occurrence, particularly the occurrence of crashes with fatal and serious injuries, is less frequent. There is a need to understand better the risks associated with geometric and roadside features along low-volume roadways in order to identify locations where preventive countermeasures may be employed. This paper describes the collection and analysis of a large sample of data from low-volume roads in Oregon to quantify the effects of geometric and roadside features on crash occurrence and associated risks. The effects of lane width, shoulder width, grade, side slope, fixed objects near the roadway, and horizontal and vertical curves have been quantified. For the low-volume road sample, roads with lanes less than 12 ft wide have a much higher crash risk than do roads with standard 12-ft lanes. Similarly, roads with narrow or no shoulders tend to have much higher crash rates than roads with shoulders 4 ft or 5 ft wide. Crash risk is shown to be much higher on curves with higher degrees of curvature compared with curves with smaller degrees of curvature.