Inertial Profiler Research Articles

Development and Implementation of Stop-and-Go Inertial Profiler Certification Procedure in California

The ride quality of a road in California is often determined by evaluating pavement smoothness using an inertial profiler (IP). Conventional IP technology, per California Test (CT) 387, requires IP operators to maintain a minimum speed of 15 mph to collect pavement-smoothness data. However, maintaining a minimum speed of 15 mph in busy urban areas or on hilly terrains can be difficult and unsafe, often requiring traffic control. Caltrans and industry have identified a new technology, the “Stop-and-Go” (SAG) IP, for collecting pavement-smoothness data at low speeds (under 15 mph) without traffic control. The previous version of CT 387 did not allow for the use of SAG IPs. To address this issue, the Pavement and Materials Partnering Committee (PMPC) evaluated SAG IP and updated CT 387. A certification procedure for SAG IP was developed, and included in CT 387, based on a series of runs using speed profiles under various braking and acceleration conditions simulating urban traffic conditions. Any SAG profiler can be certified if it meets the requirements of AASHTO R 56 and CT 387. The certification procedure was validated using qualification runs at the Caltrans certification track, along with field testing, demonstrating that SAG IPs provide similar results to conventional IPs. Based on the validation, along with the subsequent update of CT 387, the PMPC approved the implementation of SAG IPs for optional use by Caltrans and industry. These developments helped California become one of the first states to develop and implement a certification procedure for SAG IPs.

Analysis of Concentric and Eccentric Power in Flywheel Exercises Depending on the Subjects' Strength Level and Body Mass.

Asencio, P, García-Valverde, A, Albaladejo-García, C, Beato, M, Moreno-Hernández, FJ, and Sabido, R. Analysis of concentric and eccentric power in flywheel exercises depending on the subjects' strength level and body mass. J Strength Cond Res 38(8): 1394-1400, 2024-The objective of this study is to describe how flywheel exercise mechanical outputs are affected by the athletes' body mass (BM) and strength level and by the exercise type. Forty-six recreational athletes came to a laboratory 3 times. On the first day, descriptive data, squat (1 repetition maximum: 1RM) and flywheel familiarization were performed. After a second day of familiarization, subjects performed a randomized flywheel exercise-testing protocol of squat and split squat exercises. The variables used for data analysis were peak concentric power and peak eccentric power, eccentric/concentric ratio, and their relationship with 1RM/BM. Subjects were assigned to a stronger or weaker group according to their 1RM/BM ratio. Group differences were found in absolute values of eccentric overload (EOL) ( p < 0.01; effect size [ES] = 0.51) and EOL/BM ( p < 0.01; ES = 0.46) only in the split squat. Absolute power values in the concentric phase showed differences between inertial load ( p < 0.01; ES = 0.41). The stronger group did not present significant differences between inertial loads during squat ( p < 0.01; ES = 0.46), but they showed different ratios with light inertias in comparison with the weaker group ( p < 0.01; ES = 0.46). There were significant differences between groups with light inertias in split squat (nondominant) and squat exercises ( p < 0.05; ES = 0.29) in the eccentric and concentric phases ( p < 0.116; ES = 0.20). Squat and split squat exercises present different profiles depending on the training level. In conclusion, it is recommended that practitioners perform a test to understand the inertial load-power profile (concentric, eccentric, and their ratio) for each exercise and also consider the user's strength level for selection of the inertial load and for the exercise to use in training.

Application of Satellite-Based Remote Sensing for the Management of Pavement Infrastructure Assets

The long-term monitoring of transportation infrastructure assets at a lower cost and with short mobilization time is of significant interest to both state and federal transportation agencies in the U.S. Because of the significant improvement in spatial and temporal resolution of synthetic aperture radar (SAR) remote sensing systems and a notable reduction in the cost of data acquisition, SAR has now become a viable method to provide economic and rapid condition assessment of transportation assets. A research study was developed and performed to comprehensively perform the inspection and characterization of a pavement surface based on the amplitude of backscattering of an X-band radar. In situ characterization of the test site was first performed using traditional inertial profilers and aerial photogrammetry with unmanned aerial vehicle (UAV) surveys. The results from these in situ methods were compared with the corrected amplitude of the SAR data, which indicated that the distribution of surface roughness values computed from the inertial profiler, UAV, and SAR exhibited similar probability densities at various segmental lengths considered in this study. This suggested that the problematic areas that are evident during in situ characterization can be delineated and quantified based on the normalized radar cross section of the pavement surface. Overall, the outcome of this research exhibits the potential of SAR for future transportation asset management undertakings, and the systematic framework developed as a part of this research could be of significant interest to engineers and transportation practitioners.

Applications of using connected vehicle data for pavement quality analysis

Current quantitative methods to evaluate pavement conditions in the United States are most commonly focused on construction acceptance using the International Roughness Index (IRI). However, from an asset management perspective, qualitative visual inspection techniques are the most prevalent. Modern vehicles with factory-equipped sensors drive these roadways daily and can passively assess the condition of infrastructure at an accuracy level somewhere between qualitative assessment and rigorous construction acceptance techniques. This paper compares crowdsourced ride quality data with an industry standard inertial profiler on a 7-mile bi-directional construction zone. A linear correlation was performed on 14 miles of I-65 that resulted in an R2 of 0.7 and a p-value of &amp;lt;0.001, but with a modest fixed offset bias. The scalability of these techniques is illustrated with graphics characterizing IRI values obtained from 730,000 crowdsourced data segments over 5,800 miles of I-80 in April of 2022 and October 2022. This paper looks at the use of standard original equipment manufacturer (OEM) on-board sensor data from production vehicles to assess approximately 100 miles of roadway pavements before, during, and after construction. The completed construction projects observed IRI improvements of 10 in/mi to 100 in/mi. These results suggest that it is now possible to monitor pavement ride quality at a system level, even with a small proportion of connected vehicles (CV) providing roughness data.

Inertial Migration in a Pressure-Driven Channel Flow: Beyond the Segre-Silberberg Pinch.

We examine theoretically the inertial migration of a neutrally buoyant rigid sphere in pressure-driven channel flow, accounting for its finite size relative to the channel width (the confinement ratio). For sufficiently large channel Reynolds numbers (Re_{c}), a small but finite confinement ratio qualitatively alters the inertial lift velocity profiles obtained using a point-particle formulation. Finite size effects lead to new equilibria, in addition to the well-known Segre-Silberberg pinch locations. Consequently, a sphere can migrate to either the near-wall Segre-Silberberg equilibria, or the new stable equilibria located closer to the channel centerline, depending on Re_{c} and its initial position. Our findings are in accord with recent experiments and simulations, and have implications for passive sorting of particles based on size, shape, and other physical characteristics, in microfluidic applications.

Advances in Technical Assessment of Spiral Inertial Microfluidic Devices Toward Bioparticle Separation and Profiling: A Critical Review

Advances in Technical Assessment of Spiral Inertial Microfluidic Devices Toward Bioparticle Separation and Profiling: A Critical Review

Industry- and Academic-Based Trends in Pavement Roughness Inspection Technologies over the Past Five Decades: A Critical Review

Roughness is widely used as a primary measure of pavement condition. It is also the key indicator of the riding quality and serviceability of roads. The high demand for roughness data has bolstered the evolution of roughness measurement techniques. This study systematically investigated the various trends in pavement roughness measurement techniques within the industry and research community in the past five decades. In this study, the Scopus and TRID databases were utilized. In industry, it was revealed that laser inertial profilers prevailed over response-type methods that were popular until the 1990s. Three-dimensional triangulation is increasingly used in the automated systems developed and used by major vendors in the USA, Canada, and Australia. Among the research community, a boom of research focusing on roughness measurement has been evident in the past few years. The increasing interest in exploring new measurement methods has been fueled by crowdsourcing, the effort to develop cheaper techniques, and the growing demand for collecting roughness data by new industries. The use of crowdsourcing tools, unmanned aerial vehicles (UAVs), and synthetic aperture radar (SAR) images is expected to receive increasing attention from the research community. However, the use of 3D systems is likely to continue gaining momentum in the industry.

Pavement Quality Evaluation Using Connected Vehicle Data.

Modern vehicles have extensive instrumentation that can be used to actively assess the condition of infrastructure such as pavement markings, signs, and pavement smoothness. Currently, pavement condition evaluations are performed by state and federal officials typically using the industry standard of the International Roughness Index (IRI) or visual inspections. This paper looks at the use of on-board sensors integrated in Original Equipment Manufacturer (OEM) connected vehicles to obtain crowdsource estimates of ride quality using the International Rough Index (IRI). This paper presents a case study where over 112 km (70 mi) of Interstate-65 in Indiana were assessed, utilizing both an inertial profiler and connected production vehicle data. By comparing the inertial profiler to crowdsourced connected vehicle data, there was a linear correlation with an R2 of 0.79 and a p-value of &lt;0.001. Although there are no published standards for using connected vehicle roughness data to evaluate pavement quality, these results suggest that connected vehicle roughness data is a viable tool for network level monitoring of pavement quality.

Improvement of Inertial Profiler Measurements of Urban and Low-Speed Roadways

Improvement of Inertial Profiler Measurements of Urban and Low-Speed Roadways

Research on the International Roughness Index Threshold of Road Rehabilitation in Metropolitan Areas: A Case Study in Taipei City

The International Roughness Index (IRI) is the standard scale for evaluating road roughness in many countries in the world. The Taipei City government actively promotes a Road Smoothing Project and plans to complete the rehabilitation of the main and minor roads within its jurisdiction. This study aims to detect the road surface roughness in Taipei City and recommend appropriate IRI thresholds for road rehabilitation. A total of 171 asphalt concrete pavement sections in Taipei City with a total length of 803.49 km were analyzed and compared by IRI. The longitudinal profile of the detected road sections was measured using an inertial profiler. The statistical analysis showed that the IRI value prior to road leveling was mainly distributed between 5 and 8 m/km, while the IRI value after road leveling was mainly distributed between 3 and 4.5 m/km. This confirms that the implementation of the Road Smoothing Project has a significant effect on improving road smoothness. Moreover, based on the analysis results, it is recommended that the IRI threshold value for road rehabilitation in Taipei City be set at 4.50 m/km.

Development and Preliminary Evaluation of a Varying-Speed Road Profiler

Abstract The International Roughness Index (IRI) has been widely used to characterize the road ride quality in the highway engineering community. IRI is commonly obtained via the longitudinal profile data collected by a high-speed inertial profiler. It is well known that the IRI value based on an inertial profiler can be biased under low-speed or varying-speed conditions. This stems from the inherent limitation of the accelerometer embedded in the measurement system. This study proposes a different approach to solving the problem by employing three-dimension laser scanning technology. Without relying on the accelerometer to offset the vehicle vertical dynamics/vibration, the new approach uses the measurement by a line laser to transfer the elevation along the driving direction. Following this principle, a road profiler was developed and installed on a host vehicle. A preliminary evaluation of the newly developed profiler was conducted on two urban road sections in Beijing. The elevation was focused on wavelength, IRI index, and repeatability analysis. The results showed that the proposed profiler could effectively capture road elevation and accurately characterize ride quality. It was indicated that this new equipment could serve as a useful tool to better accommodate the ride quality measurement under varying-speed data collection conditions, particularly in the urban environment.

Cross-Correlation Analysis of Line Laser High-speed Inertial Profilers

Thirteen different line-laser high-speed inertial profilers from four different manufacturers were recently tested at the Florida Department of Transportation (FDOT) Inertial Profiler Test Track. The hot-mix asphalt (HMA) track incorporates both dense and open-graded sections with international roughness index (IRI) values ranging from 34 to 104 in./mi. A cross-correlation analysis was performed on the resulting ride data. The accuracy comparison was performed using a SurPro reference profiler. The profilers as a group met the AASHTO R 56 cross-correlation criteria on each section except on a smooth, open-graded section. The profilers as a group met the repeatability cross-correlation on this section, but did not meet the accuracy cross-correlation requirement. This paper presents a description of the testing program, data collection efforts and subsequent analyses and findings.

Environmental Factors and Internal Processes Contributing to the Interrupted Rapid Decay of Hurricane Joaquin (2015)

AbstractThe objective in this study is to demonstrate how two unique datasets from the Tropical Cyclone Intensity (TCI-15) field experiment can be used to diagnose the environmental and internal factors contributing to the interruption of the rapid decay of Hurricane Joaquin (2015) and then a subsequent 30-h period of constant intensity. A special CIMSS vertical wind shear (VWS) dataset reprocessed at 15-min intervals provides a more precise documentation of the large (~15 m s−1) VWS throughout most of the rapid decay period, and then the timing of a rapid decrease in VWS to moderate (~8 m s−1) values prior to, and following, the rapid decay period. During this period, the VWS was moderate because Joaquin was between large VWSs to the north and near-zero VWSs to the south, which is considered to be a key factor in how Joaquin was able to be sustained at hurricane intensity even though it was moving poleward over colder water. A unique dataset of High Definition Sounding System (HDSS) dropwindsondes deployed from the NASA WB-57 during the TCI-15 field experiment is utilized to calculate zero-wind centers during Joaquin center overpasses that reveal for the first time the vortex tilt structure through the entire troposphere. The HDSS datasets are also utilized to calculate the inertial stability profiles and the inner-core potential temperature anomalies in the vertical. Deeper lower-tropospheric layers of near-zero vortex tilt are correlated with stronger storm intensities, and upper-tropospheric layers with large vortex tilts due to large VWSs are correlated with weaker storm intensities.

Development of a global inertial consistency model to assess road safety on Spanish two-lane rural roads

The most important factors for road crash occurrence are infrastructure, vehicle, and human factors. In fact, infrastructure and its interaction with human factor have been thoroughly studied in recent years through geometric design consistency, which can be defined as how drivers’ expectations and road behavior relate.Global consistency models were calibrated in the last decade to assess road safety on an entire homogeneous road segment. However, none of them include the underlying consistency phenomenon in their formulation.Recently, a new model was developed based on the difference between the inertial operating speed profile, which represents drivers’ expectancies, and the operating speed profile, which represents road behavior. While the operating speed represents the estimated operating speed for every location along the road, the inertial operating speed aggregates for every station the operating speed effect along some distance already covered by drivers. The authors hypothesized that this ‘aggregation effect’ was connected to drivers’ expectancies, which proved to be true based on the best model fitted. However, the exact distance (or time) that should be considered to estimate the inertial operating speed still remains unknown. This paper aims to complete this model, analyzing how the inertial operating speed varies depending on different distances and periods of time. This impact is measured considering the reliability of the corresponding consistency model. The paper also covers how the inertial operating speed should be determined along the final distance or time. For this, a total of 184 homogeneous road segments along 650 km in Spain were used.

Time-Based Calibration of the Inertial Operating Speed to Enhance the Assessment of the Geometric Design Consistency

Road crashes are mainly caused by three concurrent factors: infrastructure, vehicle, and human factors. The interaction between the infrastructure and human factors leads to the concept of geometric design consistency. Recently, a global consistency model was developed based on the difference between the inertial operating speed profile and the operating speed profile. The first was defined as the weighted average operating speed of the previous road section based on distance, and represents drivers’ expectancies, whereas the second represents road behavior. However, drivers’ expectancies are related to short-term memory which declines gradually and depends on time. Thus, a time-based inertial operating speed would allow a more accurate estimation of the phenomenon. This research analyzes different periods of time and weighting distributions to identify how drivers’ expectancies should be estimated. A set of 71 homogeneous road segments located in Italy were considered in the study. As a result, 25 seconds and a convex parabolic distribution should be used to calculate the inertial operating speed profile. This new way of estimating drivers’ expectancies showed better results than those obtained based on distance. Finally, the proposed consistency model was compared with the previous models and was found to be able to assess more accurately the geometric design consistency. Therefore, the proposed consistency model is a useful tool for engineers to estimate the number of crashes so that they can incorporate road safety considerations into the geometric design of either new two-lane rural roads, or improving the existing ones.

An Area-Based Faulting Measurement Method Using Three-Dimensional Pavement Data

Faulting is one of the three performance measures recognized by the Code of Federal Regulations (CFR) for jointed concrete pavements. U.S. Federal Highway Administration rules developed for the CFR require the state Departments of Transportation to use the AASHTO Standard R 36, Standard Method for Evaluating Faulting of Concrete Pavements, for measurement of faulting. R 36 allows both manual testing using a faultmeter and automatic testing using a high-speed inertial profiler (HSIP). There is a concern in the literature that the HSIP methods are not accurate enough for network level testing of faulting. Recent studies have also shown that three-dimensional (3-D) laser technology is showing promise for providing more accurate faulting measurements. Still, there currently is not a specific method in R 36 that utilizes 3-D data for gathering faulting measurements. This paper proposes a new method that takes full advantage of the full-coverage capabilities of 3-D to measure faulting more accurately and consistently. This method uses the comparison of smoothed areas on both sides of a joint instead of a single longitudinal profile to measure elevation differences. Field tests were performed to compare the 3-D method with manual readings taken with a Georgia faultmeter on two sections of interstate in Georgia. In addition, the impact of various footprints and measuring locations of faulting measurements using this 3-D technology were quantitatively evaluated using the proposed method. Based on this case study the new proposed 3-D method appears to be appropriate to be considered to be added as a 3-D automatic method in AASHTO R 36.

Sensitivity of Tropical Cyclone Intensification to Axisymmetric Heat Sources: The Role of Inertial Stability

Abstract This study examines the influences of an axisymmetric heat source on the tangential wind structure of a tropical cyclone (TC). Specifically, the response of a TC due to the effect of convection located in varying inertial stability profiles was calculated. Using an idealized heat source, the thermodynamic efficiency hypothesis and the dynamic hypothesis for lower-level tangential wind acceleration are studied with the use of a balanced 2D model. These two frameworks for calculating the lower-level tangential wind acceleration are then compared to an idealized but thermally forced version of a nonlinear 3D model (WRF). It is found that using either of the 2D balanced model approaches to calculate the tangential wind acceleration results in an underestimation when compared to the full nonlinear simulation. In addition, the thermodynamic efficiency approach also shows a radial shift in the location of the maximum lower-level tangential wind acceleration. Sensitivity experiments in the context of the WRF Model in varying background inertial instabilities were investigated. It is shown that as the eyewall-like heating is shifted to larger values of inertial stability, there is a decrease in the induced secondary circulation in tandem with a spinup of the lower-level tangential winds. This intensification appears to be modulated by the low-level radial advection of absolute vorticity.

Kalman Filtering–Based Real-Time Inertial Profiler

Kalman Filtering–Based Real-Time Inertial Profiler

Field Monitoring of the Long Term Pavement Performance (LTPP) Warm-Mix Asphalt (WMA) Site in Oklahoma

As Warm-Mix Asphalt (WMA) moves into mainstream use, the lower WMA production temperature and injection of water in some WMA technologies have raised concerns on how it may affect short- and long-term field performance over the design life. Under the Long Term Pavement Performance (LTPP) Specific Pavement Study 10 (SPS-10) experiment initiative, the Oklahoma Department of Transportation (ODOT) constructed six testing sections with five different WMA methodologies and one HMA control section. This paper presents the application of several art-of-the-state high speed instruments to collect comprehensive array of pavement performance data for long term performance monitoring of this site. The newly developed 3D laser imaging technology is used to collect 1mm 3D surface data for the evaluation of pavement surface distress and transverse profiling for rutting. Longitudinal profiling for roughness and macro-texture for safety are acquired via a high speed inertial profiler, while pavement friction is continuously collected using a Grip Tester. Four data collection events have been performed since the construction of the site. Data collected on the WMA sections and the control HMA section are compared and evaluated for surface performance deterioration. It is demonstrated that the WMA sites using various technologies exhibit better or comparable performance relative to the conventional HMA, in terms of pavement cracking, rutting, and roughness. Aggregate properties and mixture design significantly impact the pavement macro-texture and skid resistance properties.

Wavelength sensitivity of roughness measurements using connected vehicles

ABSTRACTResearchers previously demonstrated that a roughness index called the road impact factor (RIF) is directly proportional to the international roughness index (IRI) when measured under identical conditions. A RIF-transform converts inertial signals from connected vehicle accelerometers and speed sensors to produce RIF-indices in real time. This research examines the relative sensitivities of the RIF and the IRI to variations in dominant profile wavelengths. The findings are that both indices characterise roughness from spatial wavelengths up to 2 m with equal sensitivity. However, the RIF-transform maintains its sensitivity when characterising roughness from wavelengths beyond that. The case studies used a certified inertial profiler to collect both RIF and IRI data simultaneously from five different pavement surface types. The RIF/IRI proportionality factors distributed normally among the profiles tested. This result affirms that the RIF and IRI generally agrees. However, differences in the dominant profile wavelength among pavements will produce some spread in the degree of roughness that the indices express.