This research develops a model to solve for the three-dimensional alignment of a highway segment. Code requirements are taken into consideration, and mechanisms for maintaining heavy vehicle speeds are embedded in the model. The model brings the highway alignment close to certain preferred points, and avoids restricted areas when required. Horizontal alignment is composed of design elements, including tangent segments, circular curves, and clothoid curves. Vertical alignment is represented by lines and vertical curves. Both alignments are highly compatible with code requirements in practice. The three-dimensional alignment is obtained through an iterative process. With each iteration, a new horizontal alignment was obtained through a slight adjustment of the current alignment. Subsequently, a corresponding vertical alignment was developed by solving a series of linear mixed integer optimization problems. The entire solution process was divided into three stages with different tasks, and the accuracies in each stage carefully set to achieve efficiency. Some computational examples are provided.

It is widely acknowledged that traffic information has the potential of increasing the reliability in road networks and in alleviating congestion and its negative environmental and societal side effects. However, for these beneficial collective effects to occur, reliable and accurate traffic information is a prerequisite. Building on previous research, this article presents a reliable framework for online travel time prediction for freeways, which could, for example, be used to generate traffic information messages on so-called dynamic route information panels on freeways. Central in this framework is a so-called state-space neural network (SSNN) model, which learns to predict travel times directly from data obtained from real time traffic data collection systems. In this article we show that by using an ensemble of SSNN models also a measure for the reliability of each prediction can be produced. This enables traffic managers to monitor in real time the reliability of this system without actually measuring travel times.

Reversible roadways have been used throughout the world to mitigate the effects of congestion and optimize roadway performance for more than 70 years. They have been applied on a variety of roadway types using many different methods of control to address an assortment of needs, including the movement of unbalanced directional traffic associated peak commuter periods, emergency evacuations, roadway construction work zones, and other major gatherings and events. Despite the long and varied history of reversible roadways there are a limited amount of established guidelines and standards to guide their planning, design, and operation. To overcome this lack of information the National Cooperative Highway Research Program (NCHRP) sponsored a project to investigate and document reversible roadway practices to better understand the conditions that warrant their use, their impacts on safety, operations, and the environment, and their design and implementation requirements. This paper builds upon the findings of NCHRP Synthesis 340 by highlighting and summarizing the range of reversible roadway applications and discussing how the variety of reversible roadway applications have been able to address problems despite the fact there is little standardized practices to guide their implementation or assure uniformity in their use.

Safety assessment and rational design of bridge structures requires the uncertainty associated with vehicle loads to be modeled as accurately as possible. This modeling is rendered difficult by the presence of vehicle axle weights that involve different combinations of unimodal and multimodal probability distributions with different dependence structures. In this paper, a transformation invariant approach using copula functions is proposed for the multivariate simulation of dependent axle weights of different vehicle classes. Copula based dependence modeling, which is widely used in the financial risk analysis, is applied to model and simulate three different vehicle cases with different combinations of marginal probability distributions for axle weights. The database of observed vehicle weights is based on the data collected at five locations on national highways in India. The dependence between multimodal distributions of axle weights is accurately considered and simulations are carried out. The simulated axle weights are found to be in very good agreement with the observed data. This type of simulation is useful in carrying out simulation-based reliability analysis of bridges and pavements.

Accurate quantification of aggregate gradation is essential for a better understanding of its effect on the load-carrying capacity of an asphalt mixture. This is even more applicable for stone mastic asphalt (SMA), where stone-to-stone contact forms the cornerstone of its load-carrying capacity, especially against rutting. This paper presents a mix design procedure, which is based on and adapted from the Bailey method, to objectively quantify stone-to-stone contact for SMA mixtures. A total of 16 asphalt mixtures with six different aggregate gradations and three different asphalt binder contents were studied. Volumetric analysis of specimens showed that the volume of coarse aggregate in the mixtures had a significant effect on the voids in the coarse aggregate and the voids in the mineral aggregate (VMA). The coarse aggregate stone-to-stone contact was developed when the volume of coarse aggregate was in the range of 95–105% of the rodded unit weight. Asphalt binder content at 5.5% was optimal for the designed aggregate gradation of SMA mixtures. The test results indicated that the SMA mixtures having stone-to-stone contact exhibited excellent rutting characteristics. The findings also indicated that a positive correlation existed between the rutting obtained from the wheel tracking test and the deformation strain obtained from the uniaxial creep test.

Beneficial utilization of stabilized fly ash as a structural layer in pavement construction is a common practice in the United States. At the same time, application of untreated and unstabilized fly ash in such cases is relatively rare. One such application was demonstrated at an Industry Access Truck Route in the state of Illinois. Approximately $\mathrm{60,000}{\mathrm{m}}^3$ of F-fly ash, compacted in place, was used to construct the subbase for the $7.3\mathrm{m}$ wide and $3.4\mathrm{km}$ long road. The entire road was built into three control sections, i.e., AC1, fly ash, and AC2. Control Section AC1 was $0.75\mathrm{km}$ long and was built on fine sand subgrade; the fly ash control section was $2.2\mathrm{km}$ long and was built on silty/clayey subgrade using fly ash as subbase; Control Section AC2 was $0.45\mathrm{km}$ long and was built on clayey subgrade. This paper presents the long-term postconstruction structural performance results of the fly ash control section, as compared to Control Sections AC1 and AC2. Falling weight deflectometer studies performed on the truck route have indicated all the sections of the truck route to be performing satisfactorily. The fly ash control section in particular has exhibited very good structural performance.

In light of the increasing cost of hot-mixed asphalt mixtures and the limited availability of good materials, cold in-place recycling using foamed asphalt stabilization offers an attractive alternative for rehabilitating pavements. The lack of experience—at least as far as the performance of the aforementioned technique for heavy duty pavements is concerned—led the Greek Ministry of Public Works to undertake a field experiment with the purpose of the rehabilitation of a severely damaged heavy trafficked semirigid pavement, part of the Trans European Network. In order to achieve this goal, a comprehensive monitoring and data analysis research study was performed, concentrating on the falling weight deflectometer nondestructive technique (NDT) as a major tool for the in situ evaluation (mainly in terms of deflection and layer moduli) of the recycled pavement’s early life performance. Regarding layer thickness estimation, two different approaches are used, analyzed, and thoroughly discussed, reflecting cases often encountered in practical international experience, such as the use of conventional means like coring or advanced NDT, and using the ground penetrating radar.