This paper estimates the correlations among nine vertical vibration responses on two vehicle planar models (passenger car and heavy truck) and 27 different road unevenness indicators (RUI) of longitudinal road profile. The correlation between approximation model (linear or power function) and calculated data was analyzed to indicate the ability of different RUIs for the robust reflection of the vehicle vibration response. The correlation was analyzed as a function of vehicle velocity, category of response (ride comfort and ride safety), and type of surface (asphalt concrete versus cement concrete). The aim was to compare RUIs based on the vibration response statistic (so-called response-type indexes) and RUIs based on the direct statistics of road elevation. In total, 6,984 road profile records from the Long Term Pavement Performance (LTPP) Program were processed. The results were dependent on velocity and category of vibration response and indicate high correlation not only for the response-type RUIs (International Roughness Index and Ride Number) but also for the road indexes based on the direct statistic of road profile elevation as parameters of a road spectrum (unevenness index) as well as road elevation root-mean square (RMS) values in the medium-wave or shortwave bands or straightedge indexes. About 25% of analyzed road indexes showed a correlation $R>0.8$ with the vehicle vibration response.

Road wetness is a critical parameter when it comes to preventing road slipperiness. It has so far been difficult to measure, but new measurement techniques on the market make it useful to investigate the savings opportunities within road maintenance operations. The present study tests a new sensor mounted on a road maintenance vehicle run in a maintenance district in central Sweden. The sensor that measures road surface water depth is connected to a global positioning system (GPS) system and a global system for mobile communications (GSM) phone modem. Potential savings are calculated based on the measured road surface water depth and on the amount of applied salt needed to lower the freezing point to a certain degree. The results indicate variations in water depth along the measured roads, which implies that the salt concentrations along the roads could also vary. Though the variations were smaller along the tested highway, the calculated savings could still be up to 22%. Despite the many assumptions made in the calculations, considerable savings could potentially be realized by applying such wetness measurements.

The effectiveness and cost-effectiveness of resurfacing maintenance treatments applied to low- and moderate-traffic asphalt pavements in Tennessee were evaluated based on the pavement condition data and costs of identified maintenance projects by single and multiple regression models. The investigated treatments include thin hot-mix asphalt (HMA) overlay, mill and fill, and microsurfacing. Survey results indicated that treatment service life slightly decreased as the traffic volume increased and the service life of thin HMA overlay, mill and fill, and microsurfacing are 11, 10, and 8.5 years, respectively. Linear models were established for both pretreatment and posttreatment pavement performance trends. The treatment effectiveness was calculated as the area bounded by the pretreatment and posttreatment performance curves, the lower performance threshold, and the treatment service life. It was found that traffic level and pretreatment pavement condition are significant for the effectiveness and cost-effectiveness of treatments. The effectiveness and cost-effectiveness decrease with an increase in traffic level and pretreatment pavement condition. The analyses indicated that thin HMA overlay had the highest effectiveness, followed by mill and fill, and microsurfacing; microsurfacing was the most cost-effective treatment due to its low cost.

A driver/vehicle/road closed loop dynamic simulation model considering three-dimensional (3D) alignment was established using Matlab/Simulink for reliability analysis of vehicle stability on the combined horizontal and vertical curve. Pavement friction and vehicle operating speed were considered as the random variables. The point-mass-model based performance function considering the failure model of skidding, vehicle dynamic simulation-based performance function considering the failure model of skidding, and vehicle dynamic simulation-based performance function considering the failure model of rollover were presented, respectively, according to crash types of vehicle occurring on the curve road. Monte Carlo sampling was used to solve reliability. Followed by a parametric study, the results show that the probability of skidding calculated by the vehicle dynamic simulation is larger than that by point-mass model; and the probability of failure decreases with increasing superelevation, while rises with increasing road slope. It indicates that the current horizontal curve design oversimplifies vehicle model, ignores vehicle transient responses, and separates the horizontal and vertical alignments, which could be adverse for vehicles navigating the curved road.

Real-world applications of conventional public transport technologies in urban areas might not always be feasible due to several factors that are not necessarily attributed to passenger demand, such as the very high capital and operating cost of these systems, the limited availability of real estate to expand/create new systems, and the presence of geographical and topographical barriers (e.g., mountains, valleys, and bodies of water). In such cases, unconventional public transportation technologies have found notable success in recent years in many urban areas around the world. Aerial ropeway transit (ART) technology, which is a type of aerial transportation mode in which passengers are transported in cabins that are suspended and pulled by cables, is a popular example of these technologies. The recent introduction of this technology into the urban environment, in addition to the vendors’ continuous trials to improve upon existing aerial ropeway technologies, has led to several recent advancements and improvements to the technology as illustrated by several recent implementations around the world. This article sheds some light on some of the most recent improvements in the technology specifications as well as the operation and safety considerations of ART as observed from several case studies around the world.

This paper proposes an approximate dynamic traffic assignment algorithm for the analysis of traffic conditions in large-scale road networks over several days. The time-dependent origin-destination trips are assumed to be known. A case study for evacuation of the New Orleans metropolitan area prior to the landfall of Hurricane Katrina is presented to test the efficiency and effectiveness of the proposed procedure. The model results are compared to the traffic counts collected during the evacuation and then further tested by the mesoscopic simulation-based model, DynusT. The study shows that the traffic pattern produced by the proposed procedure is a good approximation to traffic count data and that the algorithm provides a good approximation to the computations performed by DynusT.

Shared roadways have automobiles and bicycles operating in the same traveled way, which may negatively affect traffic operations; there is limited guidance on appropriate shared roadway implementation. To provide guidance on shared roadway implementation, this paper uses microsimulation models and a sensitivity analysis to evaluate automobile quality of service on shared roadways. After the sensitivity analysis, automobile quality of service is compared to bicycle quality of service on shared roadways. Using the results of the sensitivity analysis and comparison, guidance is provided on the implementation of shared roadways. This study finds that outside lane width and bicycle volume affect automobile quality of service on shared roadways. Additionally, higher values for unsignalized access points per kilometer (per mile), heavy vehicle percent, and signalized intersection crossing distance result in bicycle quality of service being less than automobile quality of service. Using this study’s findings, shared roadway implementation guidance is provided for four-lane divided urban street segments. Future research should develop shared roadway implementation guidance using microsimulation models calibrated to observed data.

A new automatic incident detection algorithm based on the available data originally collected for journey time estimation in Hong Kong is proposed in this paper. Instead of installing a greater number of expensive detectors, the proposed algorithm has proved feasible in effective traffic incident detection, with the available data collected by both video traffic detectors and automatic vehicle identification readers. The proposed algorithm extends the previous standard normal deviate algorithm in the aspects of mathematical model, input data, and detection logic. Two new traffic parameters are proposed as indicators of incidents. They are the coefficient of variation of speed at the upstream detector and the correlation coefficient of speeds of two adjacent detectors. Historical traffic and accident data on an urban road in Hong Kong are used for calibration and validation of the proposed algorithm. This proposed algorithm outperforms five existing algorithms based on the available data for journey time estimation in Hong Kong. It is expected that the proposed algorithm could be used for incident detection in cities even when data are collected only for journey time estimation.

This paper considers the problem of modeling railway track substructure. The most commonly used methodology for designing the railway substructure cross section does not considerably differ from that proposed in the 1980s. For the bearing capacity of the subgrade, the currently used design methodology implicitly meets one objective: the stresses transmitted to the subgrade must be compatible with its bearing capacity. The bearing capacity depends on the qualities and thicknesses of the soils that compose the subgrade, from the formation layer to the lower layers. In addition, railway administrations have included additional recommendations based on their experience. During the last decade, finite-element models (FEM) have been shown to be a very useful tool for designing cross sections. These models are often very complex and require a very high computational time to be solved. To reduce this complexity and computational time while remaining faithful to the reality to be modeled, this paper proposes some recommendations to develop a parameterized numerical model in three dimensions within the elastic nonlinear range under the static load of a given railway section. To adequately reproduce the real behavior of materials (elastoplastic) and the contact surfaces between very different materials adequately, artifices to use the model in the elastic range are propsed. In addition, the goodness of this design is analyzed using multilayer numerical models. This model may be a very useful tool for analyzing the behavior of different types of railway cross sections.

Daily and monthly adjustment factors have traditionally been used to expand the estimation of daily traffic volumes into average monthly and average annual traffic. However, research efforts that are devoted to developing and evaluating these factors for nonmotorized traffic, especially for cycling, are currently rare. This is attributed mainly to the lack of extensive data that can enable reliable calibration and testing of such factors. This paper explores some issues related to the development and application of daily adjustment factors for bicycle traffic. Examples include the impact of grouping daily factors by weekday/weekend and developing weather-specific factors and factors for different road classes. The analysis made use of a large data set of 500 months of daily bicycle volume data that covered 74 links in the city of Vancouver, Canada, for the years 2010 and 2011. Monthly average daily cycling volumes were estimated using different sets of factors, and the estimation accuracy was assessed and compared. It was found that developing factors for each day of the week provided similar estimation errors to grouping the factors for weekdays and weekends. In general, the best estimation results of the monthly average cycling volumes were achieved when using daily factors that are disaggregated by weather conditions. The temporal transferability of the factors was also evaluated by applying the factors from 2010 and 2011 to data from 2009. Compared to the daily factors from 2011, it was shown that the factors from 2010 provided slightly better estimation accuracies of the monthly average of daily bicycle traffic for different months in 2009. This demonstrates the degradation in the reliability of the daily adjustment factors over time, which calls for an update of these factors every few years.