crashes, but subsequent studies extended the methodology to rural and freeway crashes (3). From this research evolved the basic pedestrian crash typology, which remains a cornerstone of much of NHTSA’s pedestrian safety activity, as well as that of FHWA. Crash types describe behaviorally similar precrash actions that lead to characteristic pedestrian–motor vehicle collisions. For example, precr...

Interest in adaptive traffic signals in the USA is increasing and the use of adaptive signals is strongly supported by FHWA. There are several systems (notably SCOOT and SCATS) that are widely used throughout the world and several new adaptive products have recently been released. This paper compares and contrasts the systems that have been successfully installed in the USA and discusses their ...

In this paper by Past President’s Award for Merit in Transportation recipient Ning Li and coauthor Stephen W. Read, a serious issue is raised in current roadway departure (RD) crash research and practices. Despite the importance of RD crashes, the definitions and identification methods of the RD crashes are inconsistent, and significant differences exist in the reported RD crash deaths between ...

The Superpave gyratory compactor (SGC) is used to compact asphalt specimens for mixture testing in the Superpave system. Five companies currently manufacture SGCs for use in the United States, offering a total of eight different models. Each model employs a unique method of setting, inducing, and maintaining the specified angle of gyration. Calibration systems are required for each device for t...

In the mid 1990's the FHWA established a High Performance Concrete (HPC) program aimed at demonstrating the positive effects of utilizing HPC in bridges. Research on the benefits of using high performance concrete for bridges has shown a number of benefits. These include increased span capacities, or wider girder spacings (and hence a fewer number of girders); increased concrete compressive and...

one of the important factors in urban construction designs is noise prevention. according toresults of this study (2011-2012), a suggested model is presented for traffic noise compatible to conditions in ahvaz. data was colleted to design a model from totally 112 measuring stations, 4 weekdays and 2 intervals as rush hours, yielding to a total number of 1344 traffic noise measurements (leq) and...

OBJECTIVE To test the effectiveness of the FHWA guidelines for intersection design. METHODS In an experimental design we used kinematics measures from an instrumented vehicle and behavioral (error) data collected during on-road evaluations to quantify the effects of improved versus unimproved intersections (turn phase) and to determine if these intersections were safer (vehicular stability an...