Quantifying roadside assessment for highway safety.

Crash data in Kentucky show that the fatal crash rate on two-lane rural roads is substantially higher than on any other type of road. Improvements have been proposed at some locations on this type of road which involve either upgrading the existing two-lane road or adding lanes resulting in a four-lane road. As part of the public information process, highway officials have been asked to document the previous results of this type of construction. The objectives of this study were to: 1) identify sections of two-lane rural roadways where either the two-lane road had been realigned and reconstructed or additional lanes had been added and 2) conduct a before-and-after analysis to determine how these changes affected traffic crashes. Of the 49 locations included in the study, 25 involved adding lanes and converting to a four-lane road while the two-lane road was upgraded (realignment with wider lanes and shoulders) at 24 locations. Before the construction, the average traffic volume was almost three times higher on the roads where additional lanes were added than where the two-lane road was upgraded. The average daily traffic increased dramatically after the construction was completed with a slightly higher increase for roads where lanes were added. When all the locations are considered, there was a 51% reduction in the crash rate when the road was upgraded and a 56% reduction in the crash rate when lanes were added. The rate was reduced from 250 to 122 crashes/100 million vehicle miles (MVM) when the road was upgraded and from 258 to 114 crashes/100 MVM when lanes were added. When only the number of crashes is considered, the number of crashes per mile decreased by 39% when the road was upgraded and by 45% when lanes were added. The rate of injury or fatal crashes was reduced by 54% for upgrading the road and 55% by adding lanes, while the number of crashes per mile decreased by 43% both when the road was upgraded and when lanes were added. The overall conclusion of the study is that both upgrading two-lane rural roads and converting the road to four lanes are effective methods of reducing total crashes and injury or fatal crashes. The traffic volume would determine the appropriate alternative.

Section 404 of the Clean Water Act (CWA) mandates that state agencies and other entities perform compensatory mitigation when their activities impair jurisdictional waters. In the Commonwealth of Kentucky, the Kentucky Transportation Cabinet (KYTC) is required to pay in-lieu fees or purchase stream mitigation credits when a roadside ditch is impaired or relocated as part of a road construction project. In-lieu fees and stream mitigation credits are costly, and ditches that have suffered degraded habitat and loss of hydrogeomorphic functionality are treated as total losses when they are impacted by construction and maintenance activities. This raises the question of whether the United States Corps of Engineers (USACE) would be receptive to alternative mitigation and monitoring practices that impose a less stringent financial burden on the Kentucky Transportation Cabinet, but which still comply with CWA regulations. This report discusses methodologies used to evaluate the quality of instream and riparian habitat, Section 404 of the CWA and its implications for mitigation of lost or damaged jurisdictional ditches, and the strategies that have been used by other states to fulfill their Section 404 mitigation requirements. The authors highlight mitigation practices that depart from the norm and which place a less onerous financial burden on state transportation agencies. KYTC officials presented this report’s key findings to the USACE Louisville District Office in January 2015 in an effort to receive approval to experiment with novel restoration techniques. The USACE granted KYTC license to implement these techniques on a project-by-project basis. Before implementation on each project, the Cabinet must receive formal approval from USACE officials. Although this was not the blanket mandate that KYTC hoped for, it indicated the Louisville District is willing to study the effectiveness of alternative mitigation strategies. Despite the Cabinet’s request, USACE officials did not approve a plan to reduce post-restoration monitoring requirements. Kentucky Transportation Center (KTC) researchers suggested that KYTC perform exhaustive monitoring of the performance of completed projects that used alternative mitigation techniques. Having information on the short-, medium-, and long-term performance of these sites could – if the results are promising – pave the way to the wider adoption of alternative mitigation practices and could eventually reduce the level of post-restoration monitoring required by the USACE.

Three recently completed road construction projects were investigated to determine Kentucky Transportation Cabinet (KYTC) effectiveness in implementing project commitments (including environmental commitments). Documentation was obtained from KYTC districts in which the projects were constructed and KYTC officials involved with the projects from planning through construction were interviewed. The projects were inspected to audit completion of project commitments. Key stakeholders (officials of local governments, resource agencies, metropolitan planning organizations, interest groups, and adjacent landowners) were interviewed about the projects. They were asked to grade KYTC for implementation of project commitments using a standard report card format. The findings for these investigations are presented. The auditing procedure employed in this study can be used to rate future KYTC projects, identify problems, and suggest solutions.

This report documents an analysis of traffic crash data in Kentucky for the years of 2009 through 2013. A primary objective of this study was to determine average crash statistics for Kentucky highways. Rates were calculated for various types of highways and for counties and cities. Difference criteria were used for exposure. Average and critical numbers and rates of crashes were calculated for various types of highways in rural and urban areas. These rates used crashes identified on highways where traffic volumes were available. Improved methods of identifying crash locations have resulted in higher rates for the last couple of years. The crash rate data can be used in Kentucky’s procedure to identify locations that have abnormal rates or numbers of crashes. The other primary objective of this study was to provide data that can be used in the preparation of the problem identification portion of Kentucky’s Annual Highway Safety Plan. County and city crash statistics were analyzed. A summary of results and recommendations in several problem identification areas is presented. These general areas include; alcohol involvement, occupant protection, speed, teenage drivers, pedestrians, bicycles, motorcycles, trucks, and vehicle defects. Other areas included in the analysis for which specific recommendations were not made include, school bus crashes and train crashes. The crash data are contained in the Collision Report Analysis for Safer Highways (CRASH) data base. This data base is updated daily so the number of crashes in a given calendar year will continue to change for a substantial time after the end of that year.

This report addresses issues related to transferring the responsibility for quality control from the Kentucky Transportation Cabinet (KyTC) to construction contractors. Surveys of the KyTC, other state departments of transportation, and Kentucky highway contractors were done to identify the advantages, concerns, and modifications of the Contractor Performed Quality Control (CPQC) program. An advisory committee of experienced KyTC engineers, Federal Highway Administration representatives, and contractor representatives met periodically to identify approaches for handling key issues of the program. Several key topics related to CPQC are presented in this report, with emphasis on quality control/quality assurance (QC/QA) administration, QC/QA procedures, quality acceptance and verification testing, and CPQC training. Specific issues related to CPQC pay items in Kentucky are also discussed. Several recommendations have been proposed to enhance the program. If properly implemented, CPQC can improve a contractor's work performance and help relieve the State's burden for inspection. Additional monitoring of the program is necessary to make further improvements and to include other pay items.

A latent class analysis of single-vehicle motorcycle crash severity outcomes

Time-Scale Modification (TSM) is a well-researched field and allows for time-domain manipulation of a signal without modifying the pitch or timbre. Many TSM methods have been presented, however quantitative results on the quality of these methods are rare, with most methods reporting informal listening tests. This is likely due to the timecommitment and cost of subjective testing. Additionally, an objective measure of quality has not yet been developed that is suitable for timescaled signals. This dissertation describes the design of e ective objective measures of quality for TSM. TSM methods are, generally, single channel algorithms that give poor results when applied to multi-channel signals, as the phase relationship between channels must be maintained. This dissertation proposes a method and additional variant for maintaining the phase relationship between channels and retaining the presence in the centre of the stereo signal. The method involves pre- and post-processing the signal, with the variant processing each frame for real-time suitability. Sum and di erence transformations of the stereo signal are used for TSM and result in a large improvement in stereo phase coherence, consequently maintaining the stereo field. The proposed method produces a highquality stereo output and greatly improves quality over the independent channel processing method. It also allows for simple implementation around all existing TSM frameworks. A modification to the Epoch-Synchronous Overlap-Add (ESOLA) TSM algorithm is proposed in this dissertation. The proposed method, Fuzzy Epoch-Synchronous Overlap-Add, improves on the previous ESOLA method through cross-correlation of time-smeared epochs before overlap-adding. This reduces distortion and artefacts while the speaker's fundamental frequency is stable, as well as reducing artefacts during pitch modulation. The proposed method is tested against well-known TSM algorithms. It is preferred over ESOLA and gives similar performance to other TSM algorithms for voice signals. It is also shown that this algorithm can work effectively with solo instrument signals containing strong fundamental frequencies. No effective objective measure of quality for TSM exists. This dissertation details the creation, subjective evaluation and analysis of a dataset, for use in the development of an objective measure of quality for TSM. Comprising two parts, the training subset contains 88 source files processed using six TSM methods at 10 time-scales, while the testing subset contains 20 source files processed using three additional methods at four time-scales. The source material contains speech, solo harmonic and percussive instruments, sound effects and a range of music genres. 42,529 ratings were collected from 633 sessions using laboratory and remote collection methods. Analysis of results shows no correlation between age and quality of rating; equivalence between expert and non-expert listeners; negligible di erences between participants with and without hearing issues; and negligible di erences between testing modalities. Comparison of published objective measures and subjective scores shows the objective measures to be poor indicators of subjective quality. Initial results for a retrained objective measure of quality are presented with results approaching average loss and correlation values of subjective sessions. An objective measure of quality for time-scaled audio is proposed that makes use of the previously developed dataset and improves on reported results. The measure uses hand-crafted features and a fully connected network to predict subjective mean opinion scores. Basic and Advanced Perceptual Evaluation of Audio Quality features are used in addition to nine features specific to TSM artefacts. Six methods of alignment are explored, with interpolation of the reference magnitude spectrum to the length of the test magnitude spectrum giving the best performance. The proposed measure achieves an average Root Mean Squared Error (RMSE) of 0.490 and a mean Pearson Correlation Coe cient (PCC) of 0.864, equivalent to 97th and 82nd percentiles of subjective sessions respectively. The proposed measure is used to evaluate TSM algorithms, finding that Elastique gives the highest objective quality for solo instrument and voice signals, while the Identity Phase-Locking Phase Vocoder gives the highest objective quality for music signals and the best overall quality. Two single-ended objective quality measures for time-scaled audio are also proposed. These measure do not require a reference signal, nor alignment. Data driven features are created by either a convolutional neural network (CNN) or a bidirectional gated recurrent unit (BGRU) network, and are fed to a fully-connected network to predict subjective mean opinion scores. The proposed CNN and BGRU measures achieve an average RMSE of 0.608 and 0.576, and a mean PCC of 0.771 and 0.794, respectively. The proposed measures are used to evaluate TSM algorithms, and comparisons are provided for 16 TSM implementations. A literature review is included with required background knowledge. It includes the fundamentals of sound perception, sound capture, digital signal processing, time-scale modification methods used within research, and subjective and objective measures of quality. Full implementation of all proposed methods and measures can be found at github.com/zygurt/TSM, while the labelled dataset is available at http://ieee-dataport.org/1987.

Evaluating the safety risk of rural roadsides is critical for achieving reasonable allocation of a limited budget and avoiding excessive installation of safety facilities. To assess the safety risk of rural roadsides when the crash data are unavailable or missing, this study proposed a Bayesian Network (BN) method that uses the experts’ judgments on the conditional probability of different safety risk factors to evaluate the safety risk of rural roadsides. Eight factors were considered, including seven factors identified in the literature and a new factor named access point density. To validate the effectiveness of the proposed method, a case study was conducted using 19.42 km long road networks in the rural area of Nantong, China. By comparing the results of the proposed method and run-off-road (ROR) crash data from 2015–2016 in the study area, the road segments with higher safety risk levels identified by the proposed method were found to be statistically significantly correlated with higher crash severity based on the crash data. In addition, by comparing the respective results evaluated by eight factors and seven factors (a new factor removed), we also found that access point density significantly contributed to the safety risk of rural roadsides. These results show that the proposed method can be considered as a low-cost solution to evaluating the safety risk of rural roadsides with relatively high accuracy, especially for areas with large rural road networks and incomplete ROR crash data due to budget limitation, human errors, negligence, or inconsistent crash recordings.

The Kentucky Transportation Cabinet’s Division of Planning collects weight data, traffic volume data, and vehicle classification data. These data are used as inputs to determine equivalent single axle loads (ESALs). ESALs are used in the pavement design process to determine pavement thickness. There have been inconsistencies observed during the computation of the ESALs during the past three or four years. These inconsistencies have resulted in a significant inflation in the estimate of ESALs per year, which if used in the design process would result in significantly thicker pavements. For example, the ESALs per truck axle for rural principal arterials and rural minor arterials, between 1998 and 1999, more than doubled from, 0.275 to 0.555. Although there was only a small increase in this number after 1999, the value remained significantly higher than expected. The objective of this research study was to evaluate the weight data collection equipment, on-site calibration procedures, and sampling techniques used by the Division of Planning for the different Aggregate Classes of highways in an effort to standardize procedures used by the Division of Planning to collect weight data.

The temporal stability of factors affecting driver injury severity in run-off-road crashes: A random parameters ordered probit model with heterogeneity in the means approach

This report provides two analyses for obtaining a quantitative means of rating the condition of railroad‐highway at‐grade crossings based on their measured roughness. Phase One of this report examined 11 crossings in the Lexington area by use of a laser based inertial profiler from the Kentucky Transportation Cabinet (KYTC) and a Face Rolling Dipstick. Phase Two was a continuation of Phase One with 26 crossings examined using inertial profilers from both the KYTC and the National Center of Asphalt Technology. Objective ratings based on rideability were obtained and wheelpath profiles were measured for each crossing. Several roughness indexes were computed from the measured profiles. A correlation between these indexes and subjective rideability ratings were examined in each study. Analysis of the data showed a tendency of objective ratings to decrease as roughness increases. This study found that highway inertial profilers are not an appropriate tool for determining roughness over short distances such as railroad crossings due to their application for testing of longer distances. It is anticipated that this report will be referenced for future research on this topic.

This study created an information base to improve decisions about the replacement or rehabilitation of historic truss bridges. During the first phase of the research, information on the history and design of the 109 bridges in the study was assembled. With the assistance of historic preservation professionals, 75 of those bridges were selected for further study for their potential for rehabilitation. During the second phase, the KTC research team, engineers from the KYTC bridge division, and 12 highway district engineers, who are responsible for the day-to-day care and maintenance of the bridges, evaluated the condition and functional context of the 75 bridges. The goal was to identify those that are good candidates for preservation through rehabilitation. The district engineers were of the opinion that only 14 of the 75 bridges needed to be replaced. However, there was an additional subset of 13 bridges that, in their opinion, present some significant obstacles to preservation related to functional inadequacy or some other problem with the bridge. The bridge engineers estimated considerably higher levels of effort to preserve these 13 bridges (an average of 7.42 on a 10 point scale) than for the 48 remaining bridges (an average of 3.82 on the 10 point scale).

The Department of Environmental Analysis at the Kentucky Transportation Cabinet has expressed an interest in feature-recognition capability because it may help analysts identify environmentally sensitive features in the landscape, including those relating to historic preservation, archaeology, endangered species habitat, and geology. LIDAR Analyst and Feature Analyst are a pair of geoprocessing software packages that have been developed by Textron Systems. Using this software, users can use LIDAR data to identify finely-scaled user-specified features. The software’s automated feature extraction saves time that might otherwise be spent manually analyzing images and digitizing features. This report explores the capabilities and accuracy of this software by using LIDAR data to identify sinkholes throughout a small area in Kentucky. This report also discusses an alternative LIDAR-based geoprocessing methodology developed by the Kentucky Geological Society. The method relies on ArcGIS and Python scripting to identify sinkholes. The feasibility and applicability of these methodologies are compared, the workflow for each method is outlined, and the capabilities and limitations of each are noted. Sample results—the identification of sinkholes—from each methodology are presented. The research team found the batch processing capability built into LIDAR and Feature Analyst adequate and beneficial for smaller projects, such as projects that prioritize the extraction of buildings, trees, and forest regions.

The contents of this report reflect the views ofthe authors who are responsible for the facts and accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the University of Kentucky, the Kentucky Transportation Cabinet, nor the Federal Highway Administration. This report does not constitute a standard, specification, or regulation. The inclusion of manufacturer names and trade names are for identification purposes and are not to be considered as endorsements.

The study of earth pressure distribution on buried structures has a great practical importance in constructing highway embankments above pipes and culverts. Based on Spangler’s research, the supporting strength of a conduit depends primarily on three factors: 1) the inherent strength of the conduit; 2) the distribution of the vertical load and bottom reaction; and 3) the magnitude and distribution of lateral earth pressures which act against the sides of the structure. Rigid culverts are frequently used in Kentucky for routing streams beneath highway embankments because of rolling and mountainous terrain, numerous streams, shallow depths to bedrock, which creates unyielding foundations, and the necessity of using high fills which create large vertical stresses acting on culverts. As a means of exploring ways of reducing large vertical earth pressures acting on a buried structure, ultra-lightweight geofoam was placed in a trench above a reinforced rigid box culvert in Russell County, KY. This study provides strong evidences from both numerical model analysis and in-situ test data to indicate that geofoam is an ideal elasto-plastic material to reduce vertical load on top of a rigid culvert resting on a rigid foundation. The load on the top of a culvert can be reduced to 20% of traditional design load after 2-ft-thick geofoam is placed on top of it. Results from numerical model are more conservative when compared to actual test data. As much as 57% of settlement from geofoam has been recorded. Stresses on the top of a culvert where geofoam was placed have reached a relatively stable level which is expected at the yield point of the geofoam. This technology can be used in applications which require controlled pressure on rigid underground structure. Whether geogoam is used or not used, the model analysis and test data show that the earth pressure acting on the sidewall does not change significantly. Although the pressure acting on the sidewall is slightly higher when geofoam is used on top of the culvert only, the value is still below the design value used by the Kentucky Transportation Cabinet. Use of geofoam placed in an imperfect trench significantly reduces the vertical stresses acting on the top of the culvert.