This paper provides the latest estimates of the attributable heavy vehicle road wear cost (load-related road wear)—which is an approximation for the marginal cost of road wear—for thin bituminous-surfaced arterial roads in Australia. These estimates were based on the following approaches: (1) a statistical relationship between the road maintenance costs and a heavy vehicle road use variable; and (2) a pavement deterioration model that forms the basis of a load-related road wear model. These recent estimates of the attributable road wear cost all suggest that the fourth power law-based equivalent standard axle load (ESAL) road use variable can be used for attributing the road wear costs. This variable is in the form of the ESAL-km parameter for attributing construction and rehabilitation costs as well as maintenance (road wear) costs. Because all of these road costs are being attributed by the same parameter, this will bring attention to the deficiency of the traffic loads being simply characterized by the fourth power law that forms the basis of ESAL estimation. However, no simple replacement for the fourth power law is currently available in Australia for the attribution of pavement wear costs.

This paper summarizes research on the behavior of reformulated asphalt cements (AC) produced by different blending combinations of propane precipitated asphalt (PPA) and other petroleum-based components—soft asphalt residues and furfural heavy oils. The asphalt cements were tested fresh and under variable aging conditions. The fresh reformulated AC blends were also used to compose local typical bituminous paving mixtures with two types of aggregate—dolomite and basalt. The mixtures were tested to inspect conformation under the local standard Marshall criteria, and also for long-term moisture damage resistance. The major conclusion of this research is that high-quality and durable ACs can be produced by reformulation through blending of specific petroleum components involving PPA. These reformulated ACs cements were found to comply with all standard specifications and in many cases to exhibit superior aging resistance as compared to conventional straight-run ACs. Bituminous mixtures composed of reformulated ACs also fully complied with local specifications. When calcareous aggregates were involved, these mixtures also exhibited high durability, as expressed by their resistance to moisture damage.

The quality of the bedding sand, jointing sand, joint width, and thickness of bedding course in concrete block pavement influence the performance of the entire pavement. A review of the literature revealed a wide range of views regarding the behavior of bedding sand, jointing sand, and concrete blocks in a block pavement. This paper describes the results of a series of tests conducted to investigate the effects of changing parameters of bedding and jointing sand on pavement performance. The influence of block parameters has been presented separately as a companion paper. A laboratory-scale test was used to study these parameters based on static plate loading tests. Eight different grades of sand ranging from coarse to fine were used in the test program. The pavement responses are characterized in terms of deflection due to applied load for half of a legal single axle limit. The results indicate that coarse grade sand is preferable.

In concrete block pavements, the blocks make up the wearing surface and are a major load-spreading component of the pavement. Earlier findings were inconsistent with respect to the deflection response of concrete blocks in the pavement. This paper presents the results of a series of tests conducted to assess the influences of block shape, thickness, size, compressive strength, and laying patterns on the overall pavement performance. The test setup discussed in the companion paper was used to study these factors based on static plate loading. The effect of load repetition on the pavement behavior is discussed. The behavior of test pavements is characterized in terms of deflection. The applied load was increased in 10 KN increments, from zero to one-half the single axle legal limit. It is found that shape, size, and thickness of blocks have a significant influence on the behavior of block pavement.

This paper documents many important pavement response parameters generated from the finite-layer analytical model, 3D-Moving Load Analysis, under a variety of loading conditions. The loading conditions reported include two types of tires (conventional and wide base) and different contact stress distributions (uniform and nonuniform). The data generated from this study reveal that there is a significant difference between the responses computed with uniform (conventional assumption) and nonuniform contact tire-pavement stress distributions. This difference varies between 6 and 30%, depending on the loading conditions. Except in the case of tensile strain at the bottom of the asphalt concrete layer, the responses computed with the nonuniform stress distribution are lower. This indicates that the use of conventional load distributions is conservative, at least in the case of the estimation of pavement rutting. Vehicle speed showed significant impact on all pavement response parameters, and its influence was consistent with those measured in many field tests. The database of pavement responses presented in the study can be used to compare the performance of pavements under a variety of conditions—for example, thin versus thick pavements, wide-base versus conventional tires, slow versus high speed of the vehicle, and so on. Furthermore, the study reveals that the inclusion of contact shear stresses (longitudinal and transverse) did not significantly influence any of the important pavement response parameters.

Highway maintenance is very expensive in terms of not only costs to the responsible agencies but also disruptive delays to users. Construction and maintenance activities on two-lane two-way highways often require the closure of one lane. During certain periods of a day, the user delay associated with lane closure may be quite intolerable to motorists. A numerical method is developed to optimize work-zone scheduling and traffic control on two-lane two-way highways where one lane at a time is closed. The objective is to minimize the total cost, including maintenance, labor/equipment idle, and user-delay costs, considering traffic flows varying over time. The optimized variables (e.g., work-zone lengths and cycle times) and the sensitivity results generated from a numerical example are presented in this study.

In recent years, there has been an increased interest in the use of recycled materials in highway-related areas by state agencies and research organizations. In the present paper, guardrail posts manufactured from recycled materials are evaluated for possible use in conventional strong-post guardrail systems. Basic physical and mechanical properties of posts are determined through static laboratory tests such as flexure, creep, and density. Their response to environmental variables such as temperature, moisture, and freeze/thaw are investigated through exposure tests. The dynamic response performance of the posts is determined using pendulum impact tests. Static cantilever bending tests have shown that recycled posts are more flexible than conventional wood and steel posts; however, the ultimate load capacities for several recycled posts are comparable to that of conventional posts. The pendulum test results show that the energy absorption of some of the recycled posts is as high as that of conventional wood posts. As a result, the overall performance of recycled posts compares favorably with conventional posts.

Traffic flow has been studied numerically by solving the kinematic wave equation with the second-order Monotone Upwind Scheme of Conservation Law (MUSCL), together with the boundary and initial conditions, which are examined by a computer based random generator derived from the Erlang process of order 250. With regard to traffic mixing, a fundamental flow-density diagram of road traffic is presented, where the ratio between the optimal and jam densities is used as a single parameter; its value is predicted by assuming that fast moving vehicles have a relatively large free speed but slow moving vehicles have a smaller free speed. Simple analysis for the state equation indicates that the parameter should be in a proper range from 0.333 to 0.618 to ensure a free speed beyond the optimal traffic speed. The effects of the single parameter on the spread of traffic shock wave have been discussed. It is found that, for congested traffic flow, in the case of a given flow density at the place of inlet and exit, the effects of the parameter on the propagation speed is apparent, while in the case of assigned flow rate on the inlet and the exit boundaries, the propagation speed is slightly dependent on the parameter. The propagation of density and flow rate fluctuation can be observed clearly from the corresponding 3D presentations.

Numerous measures of effectiveness are available to evaluate a toll facility for its level of service including density, volume-to-capacity ratio, and delay. Based on field research and data analyses, delay is recommended to be the most credible measure of effectiveness for evaluating the level of service at a toll plaza. More specifically, the 85th percentile of the cumulative individual vehicular delays was found to capture the delay with better precision. An extensive database of traffic analyses for two mainline toll plazas in Orlando, Florida, representing different plaza configurations and various levels of electronic toll collection usage, was used to validate the methodology. There were 37,175 individual vehicle records used from actual field data and simulation runs from the Toll Plaza Simulation Model TPSIM. Service time was examined to determine the level a driver begins to feel discomfort and inconvenience at a toll plaza. A level of service hierarchy was established based on the conclusions of this analysis, feedback from professionals, and reference to the U.S. Highway Capacity Manual.

Several hybrid regression models that predict hot stabilized vehicle fuel consumption and emission rates for light-duty vehicles and light-duty trucks are presented in this paper. Key input variables to these models are instantaneous vehicle speed and acceleration measurements. The energy and emission models described in this paper utilize data collected at the Oak Ridge National Laboratory (ORNL) that included fuel consumption and emission rate measurements (CO, HC, and ${\mathrm{NO}}_x)$ for five light-duty vehicles and three light-duty trucks as a function of the vehicle’s instantaneous speed and acceleration levels. The fuel consumption and emission models are found to be highly accurate as compared to the ORNL data, with coefficients of determination ranging from 0.92 to 0.99. Given that the models utilize the vehicle’s instantaneous speed and acceleration levels as independent variables, these models are capable of evaluating the environmental impacts of operational-level projects including intelligent transportation systems. The models developed in this study have been incorporated within the INTEGRATION microscopic traffic simulation model to further demonstrate their application and relevance to the transportation profession. Furthermore, these models have been utilized in conjunction with global positioning system speed measurements to evaluate the energy and environmental impacts of operational-level projects in the field.

Passenger processing space estimations described in textbooks and guidebooks are based solely on peak passenger demand and personal space standards describing perceived passenger comfort. The economic aspects of facility sizing are disregarded by those methods. In this article, an analytical tool based on deterministic queuing theory is presented for determining optimal personal space, which minimizes total cost. Total cost is defined as the sum of the cost of constructing, operating, and maintaining (COM) the facility and the cost of passenger (user) inconvenience. While COM cost is derived as a function of the expected maximum queue length and personal space, passenger cost is defined as a function of average queue length and personal space. Application of the tool is demonstrated using a hypothetical data from a typical passenger check-in lobby. It is shown that optimal personal space is influenced less by unit user cost than by unit construction cost, even when scale economies exit. Moreover, the degree of elasticity and the optimal personal space are dependent on the cost functional form.