Civil Engineering

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The Department of Civil Engineering has strong affiliation with the Western Transportation Institute (WTI) and the Center for Biofilm Engineering (CBE), a graduated NSF research center. The department is also affiliated with a Montana Department of Transportation Design Unit located on the MSU campus.

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A New Approach for Identifying Safety Improvement Sites on Rural Highways: A Validation Study
(MDPI AG, 2024-02) Dhakal, Bishal; Al-Kaisy, Ahmed
The research presented in this paper examines a new proposed approach for identifying safety improvement sites on rural highways. Unlike conventional approaches, the proposed approach does not require crash history, but rather utilizes classified variables for traffic volume, geometric features, and roadside characteristics that do not require access to exact data or extensive technical expertise. The research validates the performance of the proposed approach using field data from a large sample of rural two-lane highway segments in the state of Oregon including traffic, roadway, and crash data. A mathematical model for the prediction of the EB expected number of crashes using multivariate regression analysis is developed and used as the network screening criterion. The model’s independent variables include roadway geometry, roadside characteristics, and traffic exposure, while the dependent variable is the EB expected number of crashes. Using observed crash history as a reference, the performance of the proposed approach was compared to two of the well-established methods in practice, namely, the Empirical Bayes (EB) and the potential for safety improvement (PSI) methods. The study results suggest that by using crash density for highway segments, the performance of the proposed method was lower than that of the EB and PSI methods. This is despite the high R-square value of the predictive model used in the proposed method. However, when using crash frequencies for highway segments, the performance of the proposed method was found comparable to the well-established EB and PSI methods.
A Novel Network Screening Methodology for Rural Low-Volume Roads
(Scientific Research Publishing, Inc., 2023-01) Al-Kaisy, Ahmed; Raza, Sajid
Low-volume roads (LVRs) are an integral part of the rural transportation network providing access to remote rural areas and facilitating the movement of goods from farms to markets. These roads pose unique challenges for highway agencies including those related to safety management on the highway network. Specifically, traditional network screening methods using crash history can be effective in screening rural highways with higher traffic volumes and more frequent crashes. However, these traditional methods are often ineffective in screening LVR networks due to low traffic volumes and the sporadic nature of crash occurrence. Further, many of the LVRs are owned and operated by local agencies that may lack access to detailed crash, traffic and roadway data and the technical expertise within their staff. Therefore, there is a need for more efficient and practical network screening approaches to facilitate safety management programs on these roads. This study proposes one such approach which utilizes a heuristic scoring scheme in assessing the level of risk/safety for the purpose of network screening. The proposed scheme is developed based on the principles of US Highway Safety Manual (HSM) analysis procedures for rural highways and the fundamentals in safety science. The primary application of the proposed scheme is for ranking sites in network screening applications or for comparing multiple improvement alternatives at a specific site. The proposed approach does not require access to detailed databases, technical expertise, or exact information, making it an invaluable tool for small agencies and local governments (e.g. counties, townships, tribal governments, etc.).
Capacity at All-Way Stop Control Intersections: Case Study
(SAGE Publications, 2023-08) Al-Kaisy, Ahmed; Doruk, Dorukhan
This paper presents an empirical investigation into the capacity of all-way stop-controlled (AWSC) intersections. Video data was collected over four days at an AWSC intersection site in Bozeman, Montana. The site is characterized by single-lane approaches and high level of vehicular and pedestrian traffic. Using strict protocols, video records were processed at the individual vehicle level and several information metrics were extracted for each vehicle in the data set on all approaches. Study results indicate that the total intersection capacity at the study site varied between 400 and 1,400 vehicles per hour. The study suggests that the wide range of capacity observations is largely associated with the pedestrian crossing activity at the study site. Statistical tests confirmed that both pedestrian crossing activity and the level of conflict have significant effects on intersection capacity at the 95% confidence level. For movement type, the right-turn movement was not found to have a significant effect on intersection capacity while left-turn movement was found to negatively affect the intersection capacity. The results presented in this paper offer valuable information on AWSC intersection capacity, given the limited amount of information in the literature and the dated nature of those empirical observations.
Channelized right-turn lanes at signalized intersections: the U.S. experience
(Aracne Editrice, 2012) Al-Kaisy, Ahmed; Roefaro, Sommer Ann
This paper presents an investigation into the current U.S. practice regarding the use of channelized right-turn lanes at signalized intersections, the type of traffic control used, and the safety experience of highway agencies. The study involved a literature review and a practice survey, which was distributed to all state and selected local agencies in the United States. The literature review revealed the overall lack of knowledge about the operational and safety aspects of channelized right-turn lanes explaining, to a large extent, the lack of guidance in practice. Survey results suggest a heavy reliance on engineering judgment by highway agencies in the use of channelized right-turn lanes and the selection of traffic control. Further, results confirmed a general perception in practice about the safety benefits of signal control at channelized right-turn lanes, despite the fact that such benefits were not supported by studies or statistics. The study emphasized the need for further research on the operational and safety aspects of this right-turn treatment at intersections.
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.
Empirical Bayes application on low-volume roads: Oregon case study
(Elsevier BV, 2021-12) Al-Kaisy, Ahmed; Huda, Kazi Tahsin
ntroduction: This paper investigates the Empirical Bayes (EB) method and the Highway Safety Manual (HSM) predictive methodology for network screening on low-volume roads in Oregon. Method: A study sample of around 870 miles of rural two-lane roadways with extensive crash, traffic and roadway information was used in this investigation. To understand the effect of low traffic exposure in estimating the EB expected number of crashes, the contributions of both the observed and the HSM predicted number of crashes were analyzed. Results and Conclusions: The study found that, on low-volume roads, the predicted number of crashes is the major contributor in estimating the EB expected number of crashes. The study also found a large discrepancy between the observed and the predicted number of crashes using the HSM procedures calibrated for the state of Oregon, which could partly be attributed to the unique attributes of low-volume roads that are different from the rest of the network. However, the expected number of crashes for the study sample using the HSM EB method was reasonably close to the observed number of crashes over the 10-year study period. Practical Applications: Based on the findings, it can still be very effective to use network screening methods that rely primarily on risk factors for low-volume road networks. This is especially applicable in situations where accurate and reliable crash data are not available.
Empirical examination of passing lane operational benefits on rural two-lane highways
(North Dakota University : Upper Great Plains Transportation Institute, 2010) Al-Kaisy, Ahmed; Freedman, Zachary Sebastian
This paper presents an empirical investigation into the operational benefits of passing lanes on rural two-lane highways. Two study sites in the state of Montana were used in this investigation. Performance was examined at a single location upstream and multiple locations downstream of the passing lane at each study site. Using percent followers as a performance measure, operational benefits right after the passing lane ranged between 33% and 42% at one study site and 12% to 19% at the other study site under prevalent traffic levels. Study results also suggest that operational benefits persist for a remarkable distance beyond the end of the passing lane.
Examining the Effect of Speed and Roadway Geometry on Crash Experience along a Rural Corridor
(2014-03) Watson, Donald C.; Al-Kaisy, Ahmed; Anderson, Nathan D.
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 free-flow 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.
High-Level Assessment ofStatewide GNSS-RTN Business Models
(2023-06) Al-Kaisy, Ahmed; Raza, Sajid
The applications of geospatial technologies and positioning data embrace every sphere of modern-day science and industry where geographical positioning matters. Among all other fields, geospatial technology plays a remarkable role in the transportation sector and has the potential to play an even more critical role in future autonomous transportation systems. In this regard, the GNSS-Real-Time Network (GNSS-RTN) technology is promising in meeting the needs of automation in most advanced transportation applications. The GNSS-RTN is a satellite-based positioning system that uses a network of reference stations to provide centimeter-level accuracy in positioning data in real-time. The technical aspect and working technology of GNSS-RTN are widely studied, however, only limited research has been conducted on the various GNSS-RTN business models currently in use nationally and internationally. Therefore, this study aims at assessing the various GNSS-RTN business models currently used in practice as well as those that are deemed potentially viable but have not yet moved to practice. Eight different business models were cataloged and used in the current assessment. All business models were assessed using three criteria: state control, sustainability, and state/agency costs. The findings of this research are important in helping state agencies make informed decisions as they build, expand or manage their own GNSS-RTN systems.
Investigation of performance and lane utilization within a passing lane on a two-lane rural highway
(Scientific & Academic Publishing Co., 2013) Al-Kaisy, Ahmed; Freedman, Zachary Sebastian
An investigation into platooning and passing maneuvers within a passing lane section on a rural two-lane, two-way highway was considered in this study. The study site was located on US Highway 287 between the town of Townsend and the City of Helena in the state of Montana. Traffic volumes at study site, while considered relatively low, were typical on two-lane highways in many rural states. Per-lane analysis of performance measures and lane utilization (volume split) were used to indirectly examine passing maneuvers and lane changing at successive locations within the passing lane section. For the case study site, it was evident that traffic performance became relatively stable beyond half a mile into the passing lane for the traffic volumes investigated. Therefore, results strongly suggested that most passing maneuvers already took place before the 0.5-mile station and that the actual passing lane length was well beyond the optimal length required for breaking up platoons and improving performance.
Measuring Performance on Two-Lane Highways: Empirical Investigation
(2017-01) Al-Kaisy, Ahmed; Jafari, Amirhossein; Washburn, Scott
This paper presents an empirical investigation into several performance measures for operational analysis on two-lane highways. The performance measures investigated are average travel speed, average travel speed to free-flow speed, percent followers, followers flow, followers density, percent impeded, impeded flow, and impeded density. Field data from 16 study sites in the states of Montana, Idaho, Oregon, and North Carolina representing Class 1, Class 2, and Class 3 highways were used in this study. The level of association between performance measures and some of the most important traffic variables was examined with graphical and statistical techniques. The traffic variables investigated in this study included combined flow in both directions of travel; proportion of traffic in the direction of travel, called in this study “traffic split”; percentage of heavy vehicles; and speed variance. Study results suggest that speed-related measures have weak associations with traffic variables compared with headway-related measures. Further, compound measures involving headway and traffic flow or density exhibited the highest associations with traffic variables. With regard to two-lane highway type, higher associations are exhibited at Class 1 sites compared with Class 2 and Class 3 sites. Performance measures showed the highest associations with combined flow and traffic split.
Motorists' voluntary yielding of right of way at uncontrolled midblock crosswalks with rectangular rapid flashing beacons
(2018-07) Al-Kaisy, Ahmed; Miyake, Guilherme T.; Staszcuk, Joey; Scharf, Danielle
This article presents an investigation into the motorists' voluntary yielding behavior to bicycles and pedestrians at uncontrolled midblock crosswalk locations. Two study sites in the state of Montana with light emitting diode (LED) rectangular rapid flashing beacons (RRFB) warning devices were used in this investigation. Video records were acquired at the two study sites and video data was reduced to investigate the motorist's voluntary yielding of right of way to pedestrians and bicycles as they approach the crosswalks. The study found that the motorists' voluntary yielding increased with the activation of the RRFB devices at the two study sites. This finding is very consistent with the few recent studies that reported increases in the overall yielding behavior associated with the use of those devices. The study also found that the waiting position of crosswalk user(s), the presence of children and elderly, the number of crosswalk users, and peak periods are all important factors that affect the voluntary yielding behavior of motorists. Study results suggest that the visibility of crosswalk users by motorists is very important consideration in the selection of crosswalk location. Further, the study recommends the push-button RRFB devices be located as close as practically possible to the roadway for increased device activation and motorists' voluntary yielding.
Passenger car equivalents for heavy vehicles at freeways & multilane highways: some critical issues
(Institute of Transportation Engineers, 2006-03) Al-Kaisy, Ahmed
One of the important issues affecting the accuracy of traffic analyses is heterogeneity in the vehicular traffic mix that composes a traffic stream. Typically, the majority of vehicles in a traffic stream are passenger cars or vehicles that are similar to passenger cars in physical characteristics and performance, such as sport utility vehicles, pick-up trucks and minivans. Heavy vehicles, which usually constitute the remaining smaller proportion of a traffic mix, are larger in dimension and often inferior to passenger cars in performance. Heavy vehicles consist mainly of trucks used in freight transportation, larger buses and recreational vehicles. Despite being the smaller proportion of vehicular traffic, heavy vehicles are known for their important impacts on the traffic stream. Historically, the effect of heavy vehicles on traffic flow has been accounted for through the use of passenger car equivalency factors. These factors are intended to approximate the effect of heavy vehicles and are expressed as multiples (of the effect) of an average passenger car. In the United States, the Highway Capacity Manual (HCM) provides passenger car equivalents (PCEs) for use in capacity and level of service (LOS) analyses. Using PCEs, a heterogeneous mix of vehicles in a traffic stream can be expressed in a standardized unit of traffic, such as passenger car. PCEs are considered essential in carrying out most traffic analyses.
Perceived Risk of Phoning While Driving: A Case Study from Jordan
(2015-10) Ismeik, Muhannad; Al-Kaisy, Ahmed; Al-Ansari, Khalid
The use of mobile phones while driving is banned in most countries since it impairs driving performance and is believed to increase crash risk. The aim of this research is to identify the prevalence of phoning while driving in Jordan and to examine the association between drivers’ perception of risk and potential predicting variables. A sample of 423 drivers was surveyed to gather information on their mobile phone use while driving as well as their risk perception. Data collection took place anonymously at diverse locations through a self-report questionnaire. Statistical analysis was performed to highlight the association between risk levels and drivers’ demographics and exposure characteristics. An alarming rate of 93.1% of drivers, mostly young male college students, engaged in this unsafe behavior despite being aware of the associated risk and legislative laws. Findings suggested gender, employment status, age, education level, driving experience, and daily traveled distance were associated with mobile phone use while driving. Recommendations to enhance traffic safety were proposed and further research directions were highlighted.
Performance measures on two-lane highways: Survey of practice
(2018-11) Al-Kaisy, Ahmed; Jafari, Amirhossein; Washburn, Scott; Lutinnen, Tapio; Dowling, Richard
Two-lane highways constitute a significant component of the highway system and serve an essential function for the movement of people and goods. The Highway Capacity Manual is primarily used for operational analysis on two lane highways in the U.S. and Canada. As part of a project sponsored by the National Cooperative Highway Research Program for improving two-lane highway operational analysis methodology, a practice survey was conducted to gather information on agency experiences in regards to performance measurement on two-lane highways. The survey was sent to all state Departments of Transportation in the United States and Canada. A total of 35 usable responses were received, representing 25 states and 4 Canadian provinces. This paper summarizes the results of the agency survey and presents the most important findings. Results suggest that the top three criteria for good performance measures are: sensitivity to traffic conditions, sensitivity to road conditions, and relevance to road user perception. Further, agencies identified average travel speed as the most relevant traffic flow aspect to two-lane highway operations. Other performance measures that were found meritorious were volume-to-capacity ratio and flow rate, for class I and class II highways, respectively, versus the latter measures and percent-time-spent-following for class III highways.
Practical Guidelines for Estimation of Rest Area Use on Rural Interstates and Arterial Highways
(2012-01) Al-Kaisy, Ahmed; Veneziano, David; Kirkemo, Zachary S.; Dorrington, Christopher
Rest areas perform a critical role in the highway network. These areas provide passenger vehicle occupants and heavy vehicle operators with an opportunity to use a restroom, walk around, stop for a meal, sleep for a period of time, or even pause to use a cellular phone. These activities also have a direct impact on the various aspects of rest area planning and design. Existing guidance for rest area planning and design is largely based on national trends, which may not represent patterns of use in rural states. This paper presents a series of practical guidelines that may be used in the design and rehabilitation of rest area facilities, particularly those in rural areas. The guidance was developed by the use of empirical observations of rest area use at 44 study sites in the state of Montana. Given the amount of data collected and used in this research, it is reasonable to expect that the guidelines developed are representative of a significant proportion of existing and future rest area sites in rural locales. However, each rest area is different, and careful consideration should be given when the guidelines outlined in this paper are used.
Prioritization Scheme for Proposed RWIS Sites: Montana Case Study
(2017-08) Al-Kaisy, Ahmed; Ewan, Levi A.
A model for prioritization of new proposed environmental sensor station (ESS) sites is developed and presented in this paper. The model assesses the overall merit (OM) of a proposed ESS site as part of a Road Weather Information System (RWIS) using weather, traffic, and safety data among other variables. The purpose of the proposed model is to help in selecting optimum sites for new ESS locations, which is important in guiding RWIS system expansion. Inputs to the OM model include weather index (WI), traffic index (TI), crash index, geographic coverage, and opportunistic factors. The WI at a proposed site is determined using multiple indicators of weather severity and variability. The crash index, another major input to the OM model, incorporates crash rate along the route and the percentage of weather-related crashes over the analysis period. The TI, in turn, reflects the amount of travel on the highway network in the area surrounding the proposed ESS site. The fourth input to the merit model accounts for the ESS existing coverage in the area where the proposed site is located, while the fifth and last input is concerned with the availability and ease of access to power and communications. Model coefficients are represented by weights that reflect the contribution of each input (variable) to the OM of the ESS site. Those weights are user-specified and should be selected to reflect the agency preferences and priorities. The application of the proposed merit model on sample sites in Montana demonstrated the utility of the model in ranking candidate sites using data readily available to highway agencies.
Remote Sensing of Weather and Road Surface Conditions
(2013-01) Ewan, Levi A.; Al-Kaisy, Ahmed; Veneziano, David
Advances in road weather sensing technologies have made noninvasive road weather sensors a valuable component in many intelligent transportation systems (ITS) applications. This study investigates the reliability of using such a sensor for a proposed weather-responsive variable speed limit system. The Vaisala surface state and temperature sensors (DSC-111 and DST-111) were selected for the proposed application. The sensors' ability to provide accurate and reliable data was tested under various conditions in a controlled laboratory environment. Specifically, four outputs of interest from the sensors were tested in this investigation: surface state, snow and ice depth, water depth, and grip level. Testing results showed that the sensors determined the surface state (dry, moist, wet, snowy, and icy) accurately and reliably. The sensors' snow depth readings were found to be inaccurate, while the sensors' ice depth measurements were found to be relatively close to the actual depths. For water depth, only a limited number of readings were close to the actual depths, while other readings were highly inaccurate. In an effort to test the potential of the sensor in providing reliable inputs to the proposed ITS application, a calibration was conducted for the sensor water depth measurements at various water depths and sensor installation angles. Calibration results showed that the water depth could be accurately estimated with the calibrated sensor measurements, regardless of water depth or sensor installation angle. Sensor estimates of grip level were found to be highly correlated to the coefficient of static friction for the conditions considered in this study.
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.
Speed selection at sites with restrictive alignment: the US-191 case study
(2013) Al-Kaisy, Ahmed; Krieder, T.; Pothering, R.
An investigation into the driver’s choice of speed at roadway sites with restrictive alignment is presented in this study. Specifically, the study focused on the effect of horizontal curve radii and sight distance on speed selection. Seven sites were examined in this study that are located along a 10-mile stretch of a rural high crash corridor, US 191 north of Big Sky in southwest Montana. Two of the study sites have no restrictive geometry representing base conditions, another two have restrictive curve radii, and the other three have restrictive radii and sight distances. Vehicle speeds, classification, and headways were collected at each site. The selected speeds for free-moving vehicles were compared to the legal speed limit, advisory speed, and the speeds dictated by curve radius and sight distance when applicable. Study results found that the vast majority of observed selected speeds are notably higher than the speeds found using the alignment and sight distance design equations. Results also showed that the perceived safe speeds selected by drivers are likely to be determined by the most restrictive geometric feature.