The increasingly frequent extreme weather disasters caused by global climate change have attracted more attention to adverse weather’s effect on infrastructure systems. This paper aims to establish an integrated approach to assessing adverse weather’s effect on urban rail transit facilities and to provide decision makers with a powerful tool to analyze potential risks and allocate limited sources for risk management. First, fault tree analysis is used to understand where the risks are, how the risks will occur, and what factors have the most significant effects by analyzing all possible basic events. All wind-, rain-, and snow-related adverse weather, along with human-related factors (construction leftover problems and design drawbacks), are found to potentially cause great risks. Adverse impact scenarios are summarized based on the fault tree analysis. Next, an analytic hierarchical process (AHP)–based fuzzy synthetic evaluation model is established to assess the risk level based on an evaluation index system. AHP is used to calculate the weights between the indices for each adverse weather factor. A fuzzy synthetic evaluation process is then carried out to identify the risk level of an evaluation target, an urban rail transit station, or line section. A case study on the Beijing URT Line 8 Olympic Center Station is conducted to illustrate the process of evaluation. The results show that the risk level is high and it becomes acceptable only after countermeasures are taken. Potential countermeasures regarding facility capacity, protection area management, and monitoring/inspection are then briefly discussed.

Highway agencies seek the participation of the private sector in pavement preservation, to raise revenue, share risks, and reduce project delivery costs. With public-private partnerships (PPP) representing an increasingly common approach for project delivery, recent studies have highlighted the potential of PPP and hybrid contracting (a combination of outsourcing and in-house preservation options) in enabling project-level cost savings. This paper investigates in-house and PPP practices in pavement preservation programming, and proposes a network-level hybrid approach that beneficially combines the two. Using a mixed integer programming-based optimization model and predetermined pavement preservation strategies, a holistic multiyear, multiconstraint, network-scale pavement management system methodology is described and compared with the commonly used year-by-year approach. The goal is to identify the set of recommended in-house and PPP strategies applied to a set of individual road sections, which improve the infrastructure system’s sustainability by minimizing the overall preservation cost or maximizing the condition-based benefit across the network, subject to some desired constraints, applied simultaneously. Using data from Indiana, the benefits of the multiyear, multiconstraint optimization are demonstrated, and the results show significant network-level cost savings of the proposed hybrid approach over the in-house and PPP approaches.

It is common to find a vehicle left on the shoulder, median, gore area, or on the travel lane for certain period of time. Experience from the state of Tennessee has shown that 78% of the freeway traffic-related incidents are attributable to disabled and abandoned vehicles. It is hypothesized that the longer the vehicle is left unattended within the right of way, the higher the probability of new incidents and secondary crashes. This paper utilized 2004–2010 freeway incident data in Tennessee to evaluate the effect of the length of incident durations caused by disabled and abandoned vehicles. Analysis evaluated the effect of these incidents with respect to roadway location, queue lengths, weather conditions, towing times, lane closure, and the source of incident notification. Temporal factors, including the spectra of the time of the day, the day of the week, and the seasons of the year were evaluated with respect to the number of incidents and incident durations. More disabled and abandoned vehicles were located in the left and right shoulders than in other cross-sectional positions of the roadway. Parametric hazard-based log-logistic survival model was applied to determine factors affecting abandoned and disabled vehicles incident duration. The number of closed lanes, length of the queue formed, construction zones, trucks, and towing involvement were found to be significantly associated with longer incident duration. Some of the recommendations included the expansion of the use of the highway emergency local patrol (HELP) program as the incident notifications received through it were more precise, leading to fast clearance of incidents.

This paper describes the development of Evaluation of Pavement Condition Model software (EPCM), which consists of three main elements. The first element deals with a road network definition to create a database for each road in the network to make future predictions of pavement condition. The second element evaluates the present status of asphalt pavement depending on the type, severity, and extent of distress, and then calculates the value of a pavement condition index. For each value there is certain pavement condition requiring one type of maintenance activity. The third element deals with prediction of the pavement condition in future. This element cannot be applied in Iraq now because there are no historical data for each road in the network, but after applying this model and saving the information about each road, this will become possible after drawing a curve for each asphalt pavement. The written software was applied to a case study of local road in Abo-Ghreeb city in Baghdad with a length of 1.45 km and a width of 8 m. The result of this application was that road required an asphalt overlay. According to the Abo-Ghreeb municipality, the required maintenance activity for this road was resurfacing, which is the common maintenance method in Iraq. This is different because of the independency on a fixed criterion to select a maintenance method.

According to different studies, speed reduction is considered one of the major factors in contributing road safety. For that reason, several guidelines have been recommended for maximum desirable speed reductions from tangents to horizontal curves and for maximum differentials between design and operating speeds on horizontal curves. The Interactive Highway Safety Design Model (IHSDM) Design Consistency Module presents an analysis of the relationship between speed reduction and crashes for horizontal curves on U.S. two-lane rural highways. This paper presents the relationship between speed reduction and crashes for horizontal curves on Spanish two-lane rural roads. A model for using regression analysis to predict crashes is presented. Exposure, curve length (CL), and difference in 85th-percentile speeds ($\mathrm{\Delta }{V}_{85}$) between successive tangents and horizontal curves, as well as between successive curves, are used. The model’s coefficients were different from the ones obtained for U.S. highways, although the values of the goodness-of-fit criteria were similar. In addition, the relationship between crashes and different speeds is analyzed, taking the difference in speed as a speed differential not exceeded by 85% of the drivers traveling under free-flow conditions (${\mathrm{\Delta }}_{85}V$), instead of considering it as $\mathrm{\Delta }{V}_{85}$. The two models ($\mathrm{\Delta }{V}_{85}$ versus ${\mathrm{\Delta }}_{85}V$) give very similar results.

This research investigates the factors that lead to three manners of collision (namely, rear-end, angle, and sideswipe) that occurred in the same direction of multilane interstate highways. Mixed logit (MXL) models were developed to estimate the probability of rear-end, angle, and sideswipe collisions as functions of vehicle-following attributes and other driving maneuvers immediately before collisions. The National Automotive Sampling System-General Estimates System crash data set, collected from 2005 to 2008, was used to estimate the model. This research analyzes collisions among passenger cars and trucks, with an emphasis on their vehicular characteristics. Results show that driving behavior is different when vehicular characteristics are different and when roles of the striking and struck vehicles are grouped according to cars and trucks. This research contributes to a better understanding of the differences in unsafe driving acts between cars and trucks, and implications on future policies on car and truck drivers.

This paper presents a method of designing railway sections located in horizontal arcs. The adopted procedure is universal, i.e., it creates the possibility of varying both the type and the length of the assumed transition curves. This means that the applied analytical formulas apply to the boundary conditions of the transition curves and all of the simplifications widely existing in common algorithms have been eliminated. The presented approach is especially useful in the case of analyzing data obtained from continuous satellite measurements. To create the horizontal arc, a calculation algorithm has been implemented in an original computer program that is under the authors’ development. The main features and the results obtained by the use of the program have been described in the paper on the basis of the existing geometrical layout. The authors show the process of designing a particular arc as a sequence of characteristic steps that highlight the problem of assessment. It is shown that the proposed design method allows the generation of the following alternative variants instantaneously, without any restrictions. The program also includes quality indicators to help assess the practical suitability of particular geometrical layouts.

This paper presents a microsimulation approach for developing the analytical procedure for estimating the capacity of the urban expressway section near off-ramps and on-ramps with a median exclusive bus lane (XBL). First, with a thorough analysis of the operation caused by the installation of median XBL, three factors that influence the capacity are identified. Then, a microsimulation framework is developed. Regression analysis of factors influencing the capacity is conducted for the median XBL based on the results of the microsimulation. Further, simulation experiments on capacity estimation under different scenarios are designed. Finally, the analytical model on the capacity reduction factor is established, which considers the impact of both roadway allocation from XBL and more complex interference due to the installation of XBL. A randomly chosen section with the off-ramp and on-ramp along the third ring road in Beijing is used to validate the proposed model. Because there has not been an XBL installed on the ring road expressway, a simulation model is developed for this chosen section, in which the median XBL is installed and the capacity is calculated by the proposed model. The results are compared with those from the simulation model, demonstrating that capacities obtained from the proposed model are close to the simulated ones with small relative errors. Further, a field location on Jingtong Expressway is also chosen and field data are collected for comparison with the results from the proposed model. Small relative errors are also observed. Thus, the proposed model is shown to provide a practical estimation for the capacity of the urban expressway section near off-ramps and on-ramps with a median XBL.

Controlled field studies were performed at 12 locations to evaluate the impacts of milled centerline rumble strips on exterior roadside noise adjacent to rural two-lane highways as a function of rumble strip depth and pavement type. Twenty controlled pass-bys were performed at each location using a minivan traveling at $88.5\mathrm{km}/\mathrm{h}$ (55 mph). An equal number of passes were made both while traveling on and off of the centerline rumble strips, with the latter condition providing baseline noise data. The maximum noise was recorded during each pass using a digital sound meter that was placed 15.24 m (50 ft) laterally from the centerline of the roadway at a height of 1.52 m (5 ft) above the pavement surface. Multiple linear regression models were estimated to ascertain the effects of depth and pavement type while controlling for baseline noise. The milled depth of the rumble strips was the strongest predictor of roadside noise, and this effect was stronger for hot mix asphalt pavements compared to chipsealed pavements. For every 1.5875 mm ($1/16\text{-}\mathrm{in.}$) increase in centerline rumble strip depth, roadside noise increased by 2.3 decibels on hot mix asphalt pavements, compared to 1.4 decibels on chipsealed pavements.

One of the most significant factors that affects the location of airport elements is the optimum runway orientation. In this study, a new model called Calculation of Optimum Runway Orientation (CORO) is developed with an approach different from the previous related models. All models previously developed to solve the problem of optimum runway orientation are based on the Federal Aviation Administration (FAA) wind rose methodology. Alternatively, in the new model, the number of wind observations is used directly in the calculations without grouping wind velocities; the use of wind percentages is also excluded. The new model is written in CSharp (C#) programming language, which can be operated within a Windows environment. The proposed model is tested and compared to existing methods by using two different numerical examples to ascertain its accuracy and reliability. Since the errors arising from partial coverage problem and the FAA’s assumption defined in wind rose methodology are eliminated, it can be argued easily that it is possible to obtain more accurate results from the new model.

Speed humps are designed to ensure the safety of both drivers and pedestrians. The use of speed humps on residential streets is an efficient way of controlling the speed of vehicles traveling on them. Based on observations made in a case study, different geometric combinations of speed humps are currently in use. Although there are a few guidelines that stipulate specific ranges of dimensions for the installation of speed humps, no perfect or ideal guidelines have been introduced and properly enforced by the local authorities. Therefore, because there are so many styles and inconsistent designs of the speed humps, a well-established empirical study has been implemented to develop the optimal designs of consistency models. In this study, the 85th-percentile speed reduction and discomfort level were related to the geometric design of the speed hump. The speed data were obtained by using a laser gun meter detector to attain the spot speed data at the selected speed hump location, while the vibration data collection were obtained using the triaxial acceleration transducers connected to Racelogic VBOX II SX. Multiple linear regression analyses were conducted to develop a statistical relationship between the variables. Two models were successfully developed and validated according to the statistical procedures in the study. These models can be used as a basis for the design of speed hump geometry for a selected 85th-percentile speed reduction and discomfort level.

Modern urban traffic control (UTC) systems are a key element of intelligent transportation systems (ITS). They represent the answer to the need of increased road network capacity and provide important benefits by reducing delays, stops, and travel times. Traffic parameters, measured or computed in the field, enable an UTC system to operate in a fully adaptive mode. This way, local decision units are able to follow variations in the traffic behavior and produce optimal signaling plans. Therefore, it is highly important to have this information within a distributed approach, where neighboring junctions cooperate to produce optimal control strategies. This paper aims to demonstrate the importance of different traffic parameters and how their absence affects the signaling plans and the accuracy of traffic analyses. The present study uses a local adaptation simulation option embedded in the Synchro 7 modeling tool to assess and classify these parameters according to their impact on performing efficient traffic control; the results can be deployed in any real UTC distributed system to ensure that critical information is successfully exchanged between its local decision units to maintain a fully adaptive operation.