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As part of the U.S. FHWA-sponsored Detection Technology for IVHS program, ultrasonic, microwave radar, infrared laser radar, nonimaging passive infrared, video image processing with visible and infrared spectrum imagery, acoustic array, high sampling rate inductive loop, conventional inductive loop, microloop, and magnetometer detector technologies were evaluated at freeway and surface street arterial sites in Minnesota, Florida, and Arizona. These states were chosen because they exhibited a wide range of climatic conditions. The criteria for selecting the detector evaluation sites included searching for roadways with high traffic density and suitable structures for mounting the overhead detectors. Approximately 5.9 Gbytes of digital and analog vehicle detection and signature data and more than 300 video tapes of the corresponding traffic flow were recorded. The detector outputs were time tagged and recorded on 88 Mbyte magnetic cartridges by using a data logger specifically designed and built for this project. Detectors with serial RS-232 outputs required interface software to be written for each unique data structure. Data analysis software was also written to convert the raw data into an easily accessible Paradox database format compatible with a Windows personal computer operating system. Traffic volume ground truth data, obtained by counting vehicles from the recorded video imagery, were compared with the counts from the detector outputs. Speed ground truth data, obtained by driving probe vehicles through the field of view of the detectors and noting their speed as measured by the vehicle's speedometer, were compared with the speed measurement from the detectors. Several types of detectors were found to satisfy current traffic management requirements. However, improved accuracies and new types of information, such as queue length and vehicle turning or erratic movements, may be required from detectors for future traffic management applications.

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The objective of this research was to investigate the stripping problem in bituminous mixtures using both conventional and image processing techniques (IPT). Partial factorial combinations of asphalt mixture slabs were fabricated. A Marshall mold was modified to produce slabs of 300 mm × 300 mm × 60 mm. The mixtures were prepared using different combinations: two types of aggregates (limestone and valley gravel), two asphalt penetration grades (80/100 and 60/70), three types of additives (lime, cement, and a mixture of lime and cement), and one aggregate gradation (average of ASTM boundaries). The slabs were exposed to one of four environmental conditioning techniques: wet-dry (W-D), freezing-thawing (F-T), water immersion (I), and surface bonding (S-B). Eighty-one slabs were prepared, 19 were tested without conditioning (control slabs), and the rest were exposed to different weathering conditioning. Four cores were prepared from each slab, two for the indirect tensile strength test and the others for the Marshall stability test. A normal-based camera was used to map the surfaces of the control and conditioned slabs as well as cross-sections generated from cores tested under the indirect tensile strength test. The Silicon Video Image Processing (SVIP) software was used to digitize images for the surfaces of slabs and cores. Images were analyzed to prepare statistical parameters, intensity diagrams, and histograms for intensities based on two approaches: area-based analysis and line-based analysis. Results of the analysis indicated that 1) conventional and image processing techniques proved that surface bonding increased stability and tensile strength for conditioned slabs more than for unconditioned slabs; 2) IPT predicted stripping in limestone mixtures with AC 80/100 using the retained intensity concept and this result agreed with that of retained Marshall stability (RMS); however, it did not consistently predict the stripping potential of mixtures consisting of valley gravel due to the tone intensity effect of aggregate; 3) lime additive demonstrated the best indirect tensile strength and Marshall stability; however, the additive mix consisting of lime and cement exhibited reduction in water damage for mixtures with AC 60/70; 4) slab mixtures resisted weather conditioning more than conventional cylindrical Marshall specimens; and 5) an area-based analysis scheme using peaks, not averages of intensities, was more reliable in predicting stripping than the line-based analysis, and it was more reliable for core cross-sections than slab surfaces.

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