The Effect of “Federal -Aid Swap” Programs and Davis-Bacon Prevailing Wages on Highway Construction Costs and Contractor Composition: Evidence From Iowa

“Federal-aid swap” programs allow states and local governments to bypass federal Davis-Bacon prevailing wages and Disadvantaged Business Enterprise (DBE) goals by exchanging federal funds that have been allocated to highway projects with state funds. The Iowa Department of Transportation approved a federal-aid swap program in February 2018. Using data on more than 1,200 highway construction projects in Iowa from 2016 to 2020, I find that the cost of projects in the federal-aid swap program are not statistically different from those that were not swapped, after accounting for project size and complexity, project type, and project location. Regression results indicate that Davis-Bacon prevailing wages and DBE goals have no effect on total construction costs. However, the federal-aid swap program is statistically associated with a decrease in the likelihoods that a project is covered by the Davis-Bacon Act by 10 percentage points and DBE goals by 4 percentage points. Because the payment of Davis-Bacon prevailing wages is statistically associated with an 8 percentage-point decrease in the chances that a highway project is awarded to an out-of-state contractor, the federal-aid swap program may have increased the market share of out-of-state contractors at the expense of Iowa-based contractors.

Improving Stratification Procedures and Accuracy of Annual Average Daily Traffic (AADT) Estimates for Non-Federal Aid-System (NFAS) Roads

The 2016 safety Final Rule requires states to have access to annual average daily traffic (AADT) for all public paved roads, including non-Federal aid-system (NFAS) roads. The latter account approximately for 75% of the total roadway mileage in the country making it difficult for agencies to collect traffic data on these roads. Many agencies use stratified sampling procedures to develop default AADT estimates for uncounted segments; however, there is limited guidance and information about how to stratify the network effectively. The goal of this paper is to enhance transportation agencies’ ability to improve existing stratification schemes, design new schemes, and ultimately develop more accurate AADT estimates for NFAS roads. The paper presents the results from five pilot studies that validated and compared the performance of current, updated, and new (traditional and decision-tree-based) schemes using readily available data. According to the results, the median absolute percent error of existing AADT estimates, developed by state agencies, ranged between 71% and 120%. Updating these schemes using recent counts resulted in an AADT accuracy improvement of 25%. The best-performing schemes were developed using DTs that improved the AADT accuracy of existing schemes by 41%. Overall, having more strata and very homogenous strata is better than having fewer strata and more samples within each stratum. The analysis revealed that a key to selecting an effective scheme is to determine a critical point, beyond which creating more strata improves the AADT accuracy marginally but increases the required sample size exponentially.

Understanding Police Officers’ Usage of High-Visibility Safety Apparel: The Role of Safety Ethics and Professional Appearance

High-visibility safety apparel (HVSA) is personal protective clothing that provides visual conspicuity to reduce police officers’ risk of fatality or injury from road traffic accidents. Under the current U.S. Department of Transportation’s Federal Highway Administration regulations, police officers on or near Federal-Aid highways are mandated to wear HVSA to enhance their visibility. Although wearing HVSA can significantly prevent traffic-related fatalities among police officers, studies have shown that they do not consistently, or ever, wear it. This study identifies factors influencing HVSA noncompliance among officers by exploring their perceptions of its use and efficiency. Ninety-eight police officers completed a field survey in four cities in Yavapai County, Arizona; their responses were analyzed via predictive decision tree modeling. The results indicated that officers’ HVSA-wearing behavior can be predicted by safety ethics, professional appearance, occupation risk, functionality of HVSA, and safety education. Among these predictors, safety ethics and professional appearance were the most important factors in forecasting officers’ HVSA-wearing behavior. Our study contributes to enhancing knowledge about the psychological aspects of officers’ HVSA-wearing behavior and provides implications for improving their traffic safety policies and compliance in the law enforcement community.

Environmental Health Threats to Latino Migrant Farmworkers

Approximately 75% of farmworkers in the United States are Latino migrants, and about 50% of hired farmworkers do not have authorization to work in the United States. Farmworkers face numerous chemical, physical, and biological threats to their health. The adverse effects of these hazards may be amplified among Latino migrant farmworkers, who are concurrently exposed to various psychosocial stressors. Factors such as documentation status, potential lack of authorization to work in the United States, and language and cultural barriers may also prevent Latino migrants from accessing federal aid, legal assistance, and health programs. These environmental, occupational, and social hazards may further exacerbate existing health disparities among US Latinos. This population is also likely to be disproportionately impacted by emerging threats, including climate change and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Latino migrant farmworkers are essential to agriculture in the United States, and actions are needed to protect this vulnerable population. Expected final online publication date for the Annual Review of Public Health, Volume 42 is April 2021. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.