Adult-supervised practice in learner's permit phase has a significant but limited ability to improve safe driving skills.

Objectives: Most U.S. states require adult-supervised practice for adolescent learner permit holders intending to obtain a driver's license before 18.

Driving Skills at Licensure and Time to First Crash.

Background And Objectives: Young drivers are overrepresented in crashes, and newly licensed drivers are at high risk, particularly in the months immediately post-licensure. Using a virtual driving assessment (VDA) implemented in the licensing workflow in Ohio, this study examined how driving skills measured at the time of licensure contribute to crash risk post-licensure in newly licensed young drivers.

Methods: This study examined 16 914 young drivers (<25 years of age) in Ohio who completed the VDA at the time of licensure and their subsequent police-reported crash records.

Water-in-water emulsions stabilized by self-assembled chitosan colloidal particles.

Dextran (Dex) and poly(ethylene glycol) (PEG)-based aqueous emulsions were stabilized using the self-assembled chitosan colloidal particles (CS CPs). Besides, the effects of pH, CS CPs concentration, polymer concentration, volume ratio of PEG solution to Dex solution, temperature, homogenizing speed and homogenizing time on the property of the W/W emulsions were investigated, respectively. In order to enhance the stability of the PEG-Dex emulsion, sodium tripolyphosphate was used to cross-link the CS CPs at the interface of emulsion droplets, which resulted in the stability duration for >1 year.

Novel use of a virtual driving assessment to classify driver skill at the time of licensure.

Motor vehicle crash rates are highest immediately after licensure, and driver error is one of the leading causes. Yet, few studies have quantified driving skills at the time of licensure, making it difficult to identify at-risk drivers independent driving. Using data from a virtual driving assessment implemented into the licensing workflow in Ohio, this study presents the first population-level study classifying degree of skill at the time of licensure and validating these against a measure of on-road performance: license exam outcomes.

Licensing Examination and Crash Outcomes Postlicensure in Young Drivers.

Importance: Despite US graduated driver licensing laws, young novice driver crash rates remain high. Study findings suggest comprehensive license policy that mandates driver education including behind-the-wheel (BTW) training may reduce crashes postlicensure. However, only 15 states mandate BTW training.

Effects of Steel Slag Powder and Expansive Agent on the Properties of Ultra-High Performance Concrete (UHPC): Based on a Case Study.

In view of the performance requirements of mass ultra-high performance concrete (UHPC) for the Pang Gong bridge steel cable tower in China, the UHPC incorporating of steel slag powder and hybrid expansive agents is optimized and prepared. The effects of steel slag powder and hybrid expansive agents on the hydration characteristics and persistent shrinkage of UHPC are investigated. The results indicate that 15 wt.