Research in Progress (RIP) https://rip.trb.org/ en-us Copyright © 2024. National Academy of Sciences. All rights reserved. http://blogs.law.harvard.edu/tech/rss tris-trb@nas.edu (Bill McLeod) tris-trb@nas.edu (Bill McLeod) Research in Progress (RIP) https://rip.trb.org/Images/PageHeader-wTitle-RIP.jpg https://rip.trb.org/ Sustainability of Micromobility Services: VMT Reduction and Transit Connection https://rip.trb.org/View/2190068 Fri, 02 Jun 2023 16:48:27 GMT https://rip.trb.org/View/2190068 Automated Valuation Models to Expedite Right-of-Way Acquisition Processes Within the Federal-aid Program Across the Nation. https://rip.trb.org/View/2077933 Tue, 06 Dec 2022 09:48:32 GMT https://rip.trb.org/View/2077933 Probability of Detection in Corrosion Monitoring with FE-C Coated LPFG Sensors (SN-8) https://rip.trb.org/View/1976352 Sun, 05 Jun 2022 14:19:37 GMT https://rip.trb.org/View/1976352 Development of Adjustment Factors and Bridge Load Ratings through Statistical Analyses of the NBI Database https://rip.trb.org/View/1902218 Fri, 07 Jan 2022 13:01:30 GMT https://rip.trb.org/View/1902218 Impacts of Speed on Dockless Electric Scooter Crashes (Phase II) https://rip.trb.org/View/1881795 Mon, 04 Oct 2021 11:42:19 GMT https://rip.trb.org/View/1881795 Developing Statistical Models Using Dynamic Network Modeling, Spatiotemporal Analysis, and Theories of AI to Optimize of Transportation System Management https://rip.trb.org/View/1870404 Wed, 04 Aug 2021 14:45:42 GMT https://rip.trb.org/View/1870404 Human Factors Study on the Use and Effectiveness of Innovative Safety Messages on Dynamic Message Signs https://rip.trb.org/View/1765324 Mon, 21 Jun 2021 11:52:37 GMT https://rip.trb.org/View/1765324 Evaluating Sidewalk Infrastructure Durability and Life Extension https://rip.trb.org/View/1856852 Sat, 05 Jun 2021 17:41:09 GMT https://rip.trb.org/View/1856852 Evaluating the Effects of Cooperative Perception on Avoiding Pedestrian Crashes for Connected and Automated Vehicles https://rip.trb.org/View/1853626 Mon, 24 May 2021 11:56:31 GMT https://rip.trb.org/View/1853626 A Systems-Level Analysis of Left-Turning Vehicle-Pedestrian Crashes https://rip.trb.org/View/1846422 Tue, 13 Apr 2021 16:30:32 GMT https://rip.trb.org/View/1846422 Deep reinforcement learning for multi-asset infrastructure management incorporating traffic operations adaptations and control https://rip.trb.org/View/1841539 Thu, 18 Mar 2021 11:30:13 GMT https://rip.trb.org/View/1841539 Lab Dielectric Measurement System for Asphalt Mixture Bulk Specific Gravity Determination https://rip.trb.org/View/1749087 mb) of compacted asphalt mixtures requires multiple equipment and weight measurements for different conditions which, along with the operator experience, influence the accuracy and variability of Gmb measurements. The use of a laboratory dielectric measurement system (LDMS) was explored in this study as an alternative procedure to the current AASHTO specifications for measuring Gmb. The LDMS measures the dielectric constant of a compacted asphalt concrete specimen using a ground penetrating radar (GPR) system. In Stage 1 of the project, a procedure to measure the laboratory dielectric value of a compacted asphalt concrete specimen was established. Asphalt mixtures with a range of aggregate and mixture properties (geology, nominal maximum aggregate size, binder type, RAP content, etc.) were collected. Compacted asphalt specimens of various specimen surface conditions and sizes were tested using the LDMS. The collected dielectric results were statistically analyzed to study dielectric measurement repeatability and reliability by grouping measurements at various orientations together and comparing them to all measurements of the corresponding asphalt specimen. Sensitivity analysis was also performed to study measurement accuracy and resolution for replicate dielectric measurements. It was determined that taking dielectric measurements at any 3 orientations 120 degrees apart (3 measurements total) yield repeatable dielectric measurements with acceptable accuracy. In Stage 2 of the project, a procedure to determine Gmb based on the laboratory measured dielectric value was developed. A select number of asphalt mixtures from Stage 1 work, along with their component materials (aggregates and RAP) were collected. The Al-Qadi Lahour Leng (ALL) model and the Hashin-Shtrikman (HS) model were investigated and analyzed to establish the relationship between Gmb and dielectric measurements. Based on the gathered data and statistical analyses performed in Stage 2, a procedure using the HS model and laboratory measured dielectric values of component materials was recommended to determine specimen Gmb.  The recommended procedure produces predicted values of Gmb from measured dielectric values that are within the acceptable range of two Gmb results in AASHTO T331 for most specimens evaluated. The final report is available. ]]> Wed, 04 Nov 2020 10:36:53 GMT https://rip.trb.org/View/1749087 Heterogeneity in the Relationship Between the Built Environment and Bicycling https://rip.trb.org/View/1746069 Tue, 20 Oct 2020 18:14:11 GMT https://rip.trb.org/View/1746069 Impacts of Speed on Dockless Electric Scooter Crashes https://rip.trb.org/View/1745725 Sat, 17 Oct 2020 16:30:46 GMT https://rip.trb.org/View/1745725 Flood-Frequency Analysis in the Midwest: Addressing Potential Nonstationary Annual Peak-Flow Records https://rip.trb.org/View/1728819 Wed, 12 Aug 2020 20:04:30 GMT https://rip.trb.org/View/1728819