A study on the lane validating the distribution factor on urban and rural highways

The Highway Capacity Manual prescribes level-of-service (LOS) criteria as a function of traffic density to categorize the operational conditions of both rural and urban freeway sections. This density-based level of service is ideally suited to the assessment of urban freeways when the performance must be optimized to meet high traffic demand. There is, however, some question as to whether density is the appropriate indicator of the quality of service on rural freeways, since drivers may think more in terms of psychological or emotional comfort for freeways, which generally serve long, high-speed trips and rarely experience more than moderate congestion levels. Three specific measures are examined that have at least an intuitive relationship to the concept of driver comfort: ( a) acceleration noise, which is a measure of the physical turbulence in the traffic stream; ( b) number and duration of cruise control applications, which could serve as a general indication of driver convenience or inconvenience; and ( c) percent time spent following, which is already accepted as the basis for determining the level of service on rural two-lane highways. The three candidate measures were estimated for a hypothetical section of rural freeway by simulation, using the CORSIM model. The kinematic relationships of individual vehicles within the traffic stream were estimated by postprocessing the simulation data for each second of operation. All of the measures considered in this study have conceptual appeal. All have produced interesting and potentially usable results with respect to their relationships to traffic volume. Although the simulation results are interesting, further studies focusing on driver opinions, behavior, or field measurements, or all three, would likely be necessary to support the development and recommendation of a specific set of LOS criteria that recognizes the differences between the urban and rural freeway driving environments.

This report documents the May-August 1987 study of free flow automobile and truck speeds on tangent, level and dry sections of rural interstate, rural four-lane, rural two-lane and urban interstate highways in Indiana. The results of this report show that all types of vehicles, on all types of Indiana highways, had an average free flow speed of 59.3 mph in 1987. This indicates an increase of 0.7 mph from 1986. If the two urban interstates are excluded, the average speed on all types of rural highways in Indiana becomes 59.1 mph in 1987. This also represents an increase of 0.7 mph from 1986. All types of vehicles on rural interstate highways had an average speed of 62.3 mph, which is up by 2.2 mph from 1986. This is not unexpected, due to the implementation of the 65 mph speed limit on Indiana rural interstate highways effective June 1, 1987.

Road accidents have always been one of the important reasons for fatalities and financial losses. Since road accidents on rural highways cause more serious injuries than those on urban highways, providing a suitable method to increase safety in the curves can be a significant contributor to preventing these damages. Although speed is one of the most important variables affecting highway safety, numerous studies have been performed on the reliability analysis of horizontal curves without taking the speed variable into account. The aim of this research is reliability (probability of noncompliance) assessment in the horizontal curve design using geometric design consistency criteria. The radius, superelevation, and operating speed of 19 horizontal curves were collected by field research on the Mashhad‐Torbat Heydarieh highway in Iran. Three different approaches were defined based on the geometric design consistency criterion of a single horizontal curve, and consecutively, the probability of noncompliance was calculated using these approaches. According to the obtained results, this study showed that radius enhancement increases the probability of noncompliance and the consistency level of the geometric design. Finally, the high values of the probability of noncompliance (failure) indicate that the geometric design guidelines need calibration in the design of horizontal curves, especially for higher radii.

Investigation of rheological properties and Superpave PG of PMB mixed with reclaimed asphalt pavement binders

Analysis of the Weaknesses in the Present Freeway Capacity Models for Sweden

Residents and squatters engaging in commercial activities on setbacks of both rural and urban highways is a common issue in Nigeria. These people frequently ignore the implications of traffic externalities, with traffic accidents being a significant source of concern. There have been countless occurrences where vehicles collided with individuals, residences, and businesses placed within the highway Right of Way (ROW) or setbacks, resulting in injuries, fatalities, and property damage. As a result, the purpose of this study is to evaluate highway setback dwellers’ perception of the impacts of and vulnerability to traffic accidents. The study was conducted in 12 settlements out of the 17 settlements located along a 72-kilometer length of the Kaduna-Zaria highway in Kaduna State, Nigeria. The study used a structured questionnaire to collect data from 412 respondents who were the dwellers carrying out economic activities (formal and informal) within the 45-meter highway RoW from the median of the highway. The findings show that pedestrian accidents and disturbing sight of accident scenes are big problems for communities, even though occurrences of vehicles colliding with shops and houses are rare. Despite acknowledging their business susceptibility to traffic accidents, respondents rely on faith and prayers for protection, believing the site is critical to their survival. To accomplish Sustainable Development Goal 3 of guaranteeing healthy lives and fostering well-being, authorities at all levels in Nigeria must monitor and address the actions of squatters along roads, striving for economic integration and limiting the negative consequences of traffic on them.

Compared to the motorway network, rural and urban roads are very unsafe. Advanced Driver Assistance Systems can be used to increase traffic safety, thereby improving the conditions for effective deployment of the underlying network for integrated traffic management. In this study, we have identified ADA systems that are expected to have a high impact on traffic safety by coupling characteristics of accidents to the functionality of different ADA systems. Based on the results of this study, Intelligent Speed Adaptation (ISA) and Intersection Crash Avoidance systems appeared most likely to substantially improve the safety on non-motorway roads. ISA was selected for further analysis due to the likelihood of timely deployment of the system. Microscopic simulation model was used to quantify the impacts on traffic safety for an urban highway with controlled intersections near the Dutch city of Delft. Depending on the penetration level, the results of the simulation study showed that the decrease in the total number of accidents ranges from 4% to 19%.

This report is an analysis of spot speed observations made during the 1983 summer months of June, July and August. All observations were made of free-flowing vehicles on level, tangent sections of rural and urban highways under favorable conditions. All observations were made during daylight. This is the third report with exclusively summer observations since 1975. From 1976 until 1980 (Traffic Speed Reports Nos. 95 through 114) 14 primary and secondary stations as well as another 14 randomly selected stations were monitored every quarter in conjunction with the speed certification performed for the Federal Highway Administration. Since 1981 the state and federal studies have been conducted separately. Fourteen speed monitoring stations were used for the 1983 Traffic Speed Report calculations. These stations are divided into four categories which include: four rural interstate locations, four rural four-lane locations, four rural two-lane locations and two urban interstate locations. These 14 stations are the same as the primary and secondary control stations monitored since 1975 in Indiana. Prior to 1975 only the 12 rural stations were monitored. The locations of the 12 rural stations are essentially the same since 1970 except for stations 4L-32 (formerly number 6 on US 52) and 2L-54 (formerly number 11 on US 31), which changed in 1975. The speed limit at all the stations is 55 mph. The site locations are given in Table 1 and shown in Figure 1. The vehicles were classified as Indiana or Non-Indiana Passenger Cars and light (less than 5000 lbs. gross weight) or heavy (equal to or more than 5000 lbs. gross weight) trucks. Computer analysis was performed for each vehicle classification and for combined passenger cars and combined trucks.

Traffic axle-load distribution data gleaned from state highway department truck weight studies or surveys were analyzed to produce generalized data for use in expanding the design range of a computer program for the thickness design of concrete pavements. Loadometer data for main rural, urban, and county highways were studied. Estimates are made of traffic weights and volumes common to subdivisions. The generalized data for various classes of highways and streets are for use in design when more accurate loadometer data are available.

Multi-factor coupled friction coefficient map spatiotemporal modeling and driving risk fusion for rainy roads.

Urban freeways often cut through the heart of a city, destroying neighborhoods, displacing residents, and reconfiguring street maps. These massive infrastructure projects, costing billions of dollars in transportation funds, have been shaped for the last half century by the ideas of highway engineers, urban planners, landscape architects, and architects -- with highway engineers playing the leading role. In Changing Lanes, Joseph DiMento and Cliff Ellis describe the evolution of the urban freeway in the United States, from its rural parkway precursors through the construction of the interstate highway system to emerging alternatives for more sustainable urban transportation. DiMento and Ellis describe controversies that arose over urban freeway construction, focusing on three cases: Syracuse, which early on embraced freeways through its center; Los Angeles, which rejected some routes and then built I-105, the most expensive urban road of its time; and Memphis, which blocked the construction of I-40 through its core. Finally, they consider the emerging urban highway removal movement and other innovative efforts by cities to re-envision urban transportation.

There are clear benefits to the urban free-way mode of transportation, including increased mobility and accessibility. Historically, however, they have often brought adverse impacts to the communities that they traverse. There are signs that the 1990s generation of urban freeways has been more environmentally sensitive to neighborhoods. This study tests success in urban transportation planning by evaluating the impacts of the Squaw Peak Parkway in Phoenix, Arizona. Strategies within four thematic areas characterizing urban freeway planning are examined to explain success. The household survey in adjacent neighborhoods suggests that most freeway impacts were successfully mitigated. The article concludes that important lessons were learned from the earlier decades of freeway building. At the same time, broader issues surrounding more sustainable forms of transportation were not explored, and the authors speculate that success was obtained at the project level but question the freeway’s success at the larger urban policy level.

Single-vehicle crash severity outcome prediction and determinant extraction using tree-based and other non-parametric models

This paper presents the average truck equivalency factors for four types of full-trailer trucks on uphill flexible pavements. Rising grades of 6%,12% and 18% are considered in addition to level flexible pavements. To arrive at each truck equivalency factor for the 254 full-trailer trucks studied, the axle loads were obtained from an axle load survey using permanent weighing stations. Assuming uniform motion, the axle loads on uphill pavement were calculated for different relative height of the centre of gravity of truck above pavement taking into consideration the pull force in the hook connecting both units of each full-trailer truck. The effects on average truck equivalency factor of uphill gradient, type of full-trailer truck, relative height of centre of gravity of truck, pavement structural number and terminal level of serviceability, were thoroughly studied. The paper reveals that an increase in uphill slope causes a significant increase in flexible pavement thickness especially for steep rising grades in developing countries. For rough estimation of standard single axle load applications on uphill pavements from level pavements, overall average uphill slope factors were developed. The uphill slope factor of unity for level pavement increases by about 0.038 per each 1% increase in uphill slope.

In order to detect interface flaws between bituminous and hydraulic layers of composite pavements, three-dimensional finite element simulations of the deflection under a standard axle load were carried out. The pavement layers are considered as linear elastic and the interface behaviour follows three different hypotheses: perfectly bonded, perfectly smooth and frictional. The load is moved above the flaw and the deflection curve of the pavement surface is registered. The first derivative of this last and the curvature radius are calculated numerically. Different measurement modes under moving loads are considered using either pavement fixed or vehicle fixed sensors during the measurement recording. The presence of an interface flaw does not affect significantly the deflection curve. Inversely, the first derivative of the deflection curve and the curvature radius beneath the wheel load provide suitable indicator of the flaw presence and extension.