ASSESSMENT OF POTENTIAL SITE SELECTION METHODS FOR USE IN PRIORITIZING SAFETY IMPROVEMENTS ON GEORGIA ROADWAYS

With over 40,000 people continuing to die on US roads each year, the US government has heightened the awareness of critical safety issues with the passage of SAFETEA - LU legislation in 2005. The plan requires each of the states to develop a Strategic Highway Safety Plan (SHSP) and incorporate data-driven approaches to prioritize and evaluate program outcomes; else federal funds will be redirected. Seeking to meet the new demands for data-driven approaches, many states are struggling to identify data collection/maintenance requirements for satisfying new approaches to highway safety analysis. Recent research has shown that selecting projects on the basis of crash frequencies and rates are misleading due to selection bias (such as greater emphasis on traffic volume and cash severity etc) and Regression-to-mean phenomena. There are several safety analysis techniques that are preferred over traditional rates and frequencies. These include level of service of safety, empirical bayes method using SafetyAnalyst software techniques. While all the above mentioned methods are macroscopic (giving a bigger picture of the complete road), microscopic analysis could be done using the Interactive Highway Safety Design Model (IHSDM). IHSDM is a set of software analysis tools developed by Federal Highway Administration (FHWA) to evaluate safety on two lane rural highways. This research aims at assessing the usability, data requirements, data availability and expertise required by different techniques that are deemed appropriate for safety analysis in Georgia. To streamline and reduce the scope of work, Cobb County was chosen as the analysis county because it had been used in a prior development effort and was expected to have the best level of completion and accuracy in the state. The procedure of using the state-of-the-art analytical tools is considered as the most comprehensive safety analysis method. Cobb County data set will be used to test the applicability of the four analysis methods: crash frequency, crash rate, critical crash rate and level of service of safety (LOSS). The results from various ranking criteria (crash frequency, crash rate, critical crash rate and LOSS) will be compared to the actual available crash data and enhanced SafetyAnalyst data. SafetyAnalyst uses the Safety Performance Functions generated for northern states and it calibrated to Georgia data. SPFs applicable to Georgia data (generated from Cobb County) are compared to the non-calibrated and calibrated SPFs used in SafetyAnalyst. Analysis of costs and potential benefit of using various network screening methods is carried out to weigh the capabilities and limitations of various ranking methods

DEVELOPMENT OF GUIDANCE FOR STATES TRANSITIONING TO NEW SAFETY ANALYSIS TOOLS

With about 125 people dying on US roads each day, the US Department of Transportation heightened the awareness of critical safety issues with the passage of SAFETEA - LU (Safe Accountable Flexible Efficient Transportation Equity Act - a Legacy for Users) legislation in 2005. The legislation required each of the states to develop a Strategic Highway Safety Plan (SHSP) and incorporate data-driven approaches to prioritize and evaluate program outcomes: Failure to do so resulted in funding sanctioning. In conjunction with the legislation, research efforts have also been progressing toward the development of new safety analysis tools such as IHSDM (Interactive Highway Safety Design Model), SafetyAnalyst and HSM (Highway Safety Manual). These software and analysis tools are comparatively more advanced in statistical theory and level of accuracy, and have a tendency to be more data intensive. A review of the 2009 five-percent reports and excerpts from the nationwide survey revealed astonishing facts about the continuing use of traditional methods including crash frequencies and rates for site selection and prioritization. The intense data requirements and statistical complexity of advanced safety tools are considered as a hindrance to their adoption. In this context, this research aims at identifying the data requirements and data availability for SafetyAnalyst and HSM by working with both the tools. This research sets the stage for working with the Empirical Bayes approach by highlighting some of the biases and issues associated with the traditional methods of selecting projects such as greater emphasis on traffic volume and regression-to-mean phenomena. Further, the not-so-obvious issue with shorter segment lengths, which effect the results independent of the methods used, is also discussed. The more reliable and statistically acceptable Empirical Bayes methodology requires safety performance functions (SPFs), regression equations predicting the relation between crashes and exposure for a subset of roadway network. These SPFs, specific to a region and the analysis period are often unavailable. Calibration of already existing default national SPFs to the state\u27s data could be a feasible solution, but, how well the state\u27s data is represented is a legitimate question. With this background, SPFs were generated for various classifications of segments in Georgia and compared against the national default SPFs used in SafetyAnalyst calibrated to Georgia data. Dwelling deeper into the development of SPFs, the influence of actual and estimated traffic data on the fit of the equations is also studied questioning the accuracy and reliability of traffic estimations. In addition to SafetyAnalyst, HSM aims at performing quantitative safety analysis. Applying HSM methodology to two-way two-lane rural roads, the effect of using multiple CMFs (Crash Modification Factors) is studied. Lastly, data requirements, methodology, constraints, and results are compared between SafetyAnalyst and HSM

Safety Impacts of Converting Two-Way Left-Turn Lanes to Raised Medians and Associated Design Concerns

Raised medians and two-way left-turn lanes (TWLTLs) are the two most common types of median treatments on arterial streets. This paper aims to conduct a detailed study on the safety impacts of conversion from TWLTLs to raised medians on state roads in Florida. In addition, the study also investigated several potential safety concerns related to raised medians on state roads, including crashes at median openings, vehicles directly hitting the median curb, and median crossover crashes. Based on data availability, 17.51 miles of urban arterial sections in Florida that were converted from TWLTLs to raised medians were analyzed. Police reports of all the crashes before and after median conversion were reviewed to correct miscoded crash types and obtain additional detailed crash information. Overall, a 28.5% reduction in total crash rate was observed after the 10 study locations were converted from TWLTLs to raised medians. The reductions in the proportions of left-turn and right-turn crashes were statistically significant, while the changes in the proportions of other crash types were not statistically significant. Furthermore, the crash data did not show evidence that raised medians are an additional hazard compared with TWLTLs

Identifying Traffic Safety Practices and Needs of Local Transportation and Law Enforcement Agencies

As part of the effort to implement the Strategic Highway Safety Plan (SHSP), state departments of transportation are looking to reach out to local and law enforcement agencies. This paper presents a study by the Florida Department of Transportation (FDOT) to identify the existing safety practices and needs of local transportation agencies and law enforcement offices in Florida. Two comprehensive online surveys targeting local transportation agencies and law enforcement agencies are developed. The survey for local transportation agencies includes 39 questions on topics including standardization of crash analysis methods, training needs, and working with FDOT. For law enforcement agencies, the survey includes 25 questions covering topics on enforcement locations, traffic violations and safety campaigns, use of crash reports, and working with transportation agencies. Results from both surveys and lessons learned are discussed

Strategies to Mitigate Wrong-Way Driving Incidents on Arterials [Summary]

The researchers summarized existing studies of WWD on arterials and WWD countermeasures. They also examined the role of public outreach in reducing WWD incidents. The researchers surveyed safety practitioners across the state to discover if public education about WWD was being conducted, if respondents thought it would be helpful, and what format might be the most effective. The researchers then examined the statistics of WWD incidents on arterials in Florida. Police reports of all such crashes were obtained for 2012-2016. The reports were reviewed in detail, and elements related to the crash, such as lighting conditions, speed, driver age, and impairment, etc., were compiled. For each crash, roadway characteristics were identified. This analysis provided an overview of WWD incidents on arterials. For example, over half of WWD incidents occurred at intersections, and over half occurred during dark hours

Performance Evaluation of Connected Vehicle (CV) and Transportation Systems Management and Operations (TSM&O) Projects in Florida [Summary]

BDV29-977-64Technology that connects human experience with artificial intelligence is increasingly reaching every sector of society \u2013 including Florida\u2019s transportation network. To stay ahead of this curve, the Florida Department of Transportation (FDOT) currently has 33 deployed projects that explore this interconnectivity through Connected Vehicle (CV) technologies and Transportation Systems Management and Operations (TSM&O) strategies

Performance Evaluation of Connected Vehicle (CV) and Transportation Systems Management and Operations (TSM&O) Projects in Florida

BDV29-977-64Connected vehicle (CV) technologies and Transportation Systems Management and Operations (TSM&O) strategies are increasingly being considered by transportation agencies to improve the safety and mobility of the transportation network. To fully understand the potential benefits of CV and TSM&O initiatives, it is crucial to not only identify the performance measures used to evaluate the progress of each initiative, but also to estimate the benefit-to-cost (B/C) ratios to justify the funding requests associated with implementing these technologies and strategies. The primary goal of this research was to assist the Florida Department of Transportation (FDOT) in developing approaches to evaluate the performance of CV projects and current TSM&O strategies being deployed, including the Rapid Incident Scene Clearance (RISC) program, the Road Ranger Service Patrol (RRSP) program, and the Smart Work Zone (SWZ) TSM&O strategies. A comprehensive review of the existing body of literature was conducted to identify the quantitative and qualitative performance measures and metrics that are being considered in evaluating the performance of CV deployments and TSM&O strategies. B/C analyses were conducted to quantify the mobility and safety benefits associated with implementing the RISC and RRSP programs. Results indicate that for every dollar spent on the RISC program, $5.78 is returned in secondary crash savings, and$1.20 is returned in incident-related traffic delay savings. For every dollar spent on the RRSP program, $5.15 is returned in secondary crash savings, and$7.44 is returned in incident-related traffic delay savings. The study also discussed the potential safety and mobility benefits of Smart Work Zone (SWZ) technologies. Performance criteria and evaluation metrics were also developed for the different stages of the CV project development process (i.e., pre-project phase, planning phase, design-deploy-test phase, and the operations & maintenance phase). The performance criteria of two CV deployments in Florida (Gainesville Signal Phase and Timing (SPaT) Project and I-4 Florida\u2019s Regional Advanced Mobility Elements (I-4 FRAME) Project) were also reviewed. Findings from this research offer guidance in evaluating the effectiveness of CV and TSM&O initiatives. Evaluation criteria and approaches presented in this report can better prepare FDOT for deployments

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

Background: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. Methods: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. Findings: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. Interpretation: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic

Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950–2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021

BACKGROUND: Estimates of demographic metrics are crucial to assess levels and trends of population health outcomes. The profound impact of the COVID-19 pandemic on populations worldwide has underscored the need for timely estimates to understand this unprecedented event within the context of long-term population health trends. The Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 provides new demographic estimates for 204 countries and territories and 811 additional subnational locations from 1950 to 2021, with a particular emphasis on changes in mortality and life expectancy that occurred during the 2020–21 COVID-19 pandemic period. METHODS: 22 223 data sources from vital registration, sample registration, surveys, censuses, and other sources were used to estimate mortality, with a subset of these sources used exclusively to estimate excess mortality due to the COVID-19 pandemic. 2026 data sources were used for population estimation. Additional sources were used to estimate migration; the effects of the HIV epidemic; and demographic discontinuities due to conflicts, famines, natural disasters, and pandemics, which are used as inputs for estimating mortality and population. Spatiotemporal Gaussian process regression (ST-GPR) was used to generate under-5 mortality rates, which synthesised 30 763 location-years of vital registration and sample registration data, 1365 surveys and censuses, and 80 other sources. ST-GPR was also used to estimate adult mortality (between ages 15 and 59 years) based on information from 31 642 location-years of vital registration and sample registration data, 355 surveys and censuses, and 24 other sources. Estimates of child and adult mortality rates were then used to generate life tables with a relational model life table system. For countries with large HIV epidemics, life tables were adjusted using independent estimates of HIV-specific mortality generated via an epidemiological analysis of HIV prevalence surveys, antenatal clinic serosurveillance, and other data sources. Excess mortality due to the COVID-19 pandemic in 2020 and 2021 was determined by subtracting observed all-cause mortality (adjusted for late registration and mortality anomalies) from the mortality expected in the absence of the pandemic. Expected mortality was calculated based on historical trends using an ensemble of models. In location-years where all-cause mortality data were unavailable, we estimated excess mortality rates using a regression model with covariates pertaining to the pandemic. Population size was computed using a Bayesian hierarchical cohort component model. Life expectancy was calculated using age-specific mortality rates and standard demographic methods. Uncertainty intervals (UIs) were calculated for every metric using the 25th and 975th ordered values from a 1000-draw posterior distribution. FINDINGS: Global all-cause mortality followed two distinct patterns over the study period: age-standardised mortality rates declined between 1950 and 2019 (a 62·8% [95% UI 60·5–65·1] decline), and increased during the COVID-19 pandemic period (2020–21; 5·1% [0·9–9·6] increase). In contrast with the overall reverse in mortality trends during the pandemic period, child mortality continued to decline, with 4·66 million (3·98–5·50) global deaths in children younger than 5 years in 2021 compared with 5·21 million (4·50–6·01) in 2019. An estimated 131 million (126–137) people died globally from all causes in 2020 and 2021 combined, of which 15·9 million (14·7–17·2) were due to the COVID-19 pandemic (measured by excess mortality, which includes deaths directly due to SARS-CoV-2 infection and those indirectly due to other social, economic, or behavioural changes associated with the pandemic). Excess mortality rates exceeded 150 deaths per 100 000 population during at least one year of the pandemic in 80 countries and territories, whereas 20 nations had a negative excess mortality rate in 2020 or 2021, indicating that all-cause mortality in these countries was lower during the pandemic than expected based on historical trends. Between 1950 and 2021, global life expectancy at birth increased by 22·7 years (20·8–24·8), from 49·0 years (46·7–51·3) to 71·7 years (70·9–72·5). Global life expectancy at birth declined by 1·6 years (1·0–2·2) between 2019 and 2021, reversing historical trends. An increase in life expectancy was only observed in 32 (15·7%) of 204 countries and territories between 2019 and 2021. The global population reached 7·89 billion (7·67–8·13) people in 2021, by which time 56 of 204 countries and territories had peaked and subsequently populations have declined. The largest proportion of population growth between 2020 and 2021 was in sub-Saharan Africa (39·5% [28·4–52·7]) and south Asia (26·3% [9·0–44·7]). From 2000 to 2021, the ratio of the population aged 65 years and older to the population aged younger than 15 years increased in 188 (92·2%) of 204 nations. INTERPRETATION: Global adult mortality rates markedly increased during the COVID-19 pandemic in 2020 and 2021, reversing past decreasing trends, while child mortality rates continued to decline, albeit more slowly than in earlier years. Although COVID-19 had a substantial impact on many demographic indicators during the first 2 years of the pandemic, overall global health progress over the 72 years evaluated has been profound, with considerable improvements in mortality and life expectancy. Additionally, we observed a deceleration of global population growth since 2017, despite steady or increasing growth in lower-income countries, combined with a continued global shift of population age structures towards older ages. These demographic changes will likely present future challenges to health systems, economies, and societies. The comprehensive demographic estimates reported here will enable researchers, policy makers, health practitioners, and other key stakeholders to better understand and address the profound changes that have occurred in the global health landscape following the first 2 years of the COVID-19 pandemic, and longer-term trends beyond the pandemic. FUNDING: Bill & Melinda Gates Foundation

Quantifying the Mobility Benefits of Express Lanes using Real-Time Traffic Data

Traffic congestion is one of the major problems facing transportation agencies, especially in urban areas. Agencies are exploring ways to use the existing transportation infrastructure efficiently by deploying appropriate traffic management strategies. One of these strategies is the use of express lanes, which are expected to effectively mitigate congestion and increase the reliability of highway facilities. Express lanes are managed toll lanes, separated from general-purpose lanes within a freeway facility. The goal of this study was to quantify the mobility benefits of express lanes by comparing the performance of express lanes with that of their adjacent general-purpose lanes, and by assessing the performance of the general-purpose lanes when the express lanes were open versus when the express lanes were closed. The Buffer Index (BI), a travel time reliability measure, was selected as the performance measure. The analysis was based on 95Express, express lanes along I-95 in Miami, Florida. Overall, the results indicated that BIs for the express lanes were significantly lower than the BIs for the general-purpose lanes, and the BIs for the general-purpose lanes were significantly lower when the express lanes were open compared with the periods when the express lanes were closed. The study results showed mobility improvements on both the express lanes and the general-purpose lanes, although the extent of the improvements varied by direction (i.e., northbound and southbound) and time of day (i.e., a.m. peak, p.m. peak, daytime off-peak, and nighttime off-peak). Transportation agencies may use these findings to quantify and evaluate the mobility benefits of the express lanes and the general-purpose lanes on express lane facilities