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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Item Passenger car equivalents for heavy vehicles at freeways & multilane highways: some critical issues(Institute of Transportation Engineers, 2006-03) Al-Kaisy, AhmedOne 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.Item Static warning signs of occasional hazards: do they work?(Institute of Transportation Engineers, 2008-06) Al-Kaisy, Ahmed; Hardy, Amanda; Nemfakos, CharlesHighway agencies expend significant resources on the installation, upgrading and maintenance of traffic control devices. To ascertain that those resources are well invested, it is important to know whether traffic control devices serve their intended purpose. The answer may be easy for some traffic control devices such as traffic signals, regulatory signs and guide signs, but it may be more difficult for other devices such as warning signs in general and those intended for occasional hazards in particular. Examples of these occasional hazards are railroad crossings, icy bridges, unexpected alignment and/or geometry, falling rocks, wildlife crossings, etc. For regulatory and guide signs, drivers feel an “obligation” to use the information provided by those signs; in the case of warning signs, the use of information and drivers’ reactions seem to be based more on perception of risk. The effectiveness of static warning signs for occasional hazards is questionable because those signs typically are posted with out the hazard being perceived by drivers. Subsequently, highway agencies have begun to question the feasibility of expending significant resources on the installation and maintenance of these signs when little evidence exists regarding their effectiveness in improving highway safety. Knowing the effectiveness of these signs in improving safety is important for highway agencies to assess the feasibility of using conventional signs and whether alternative warning devices are required for a safer highway environment.Item 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 SebastianAn 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.Item 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 SebastianThis 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.Item Channelized right-turn lanes at signalized intersections: the U.S. experience(Aracne Editrice, 2012) Al-Kaisy, Ahmed; Roefaro, Sommer AnnThis 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.