Traumatic Brain Injury in Iowa Inpatient Hospital Data, 2003-2005

According to the Centers for Disease Control and Prevention, unintentional injury is the fifth leading cause of death for all age groups and the first leading cause of death for people from 1 to 44 years of age in the United States, while homicide remains the 2nd leading cause of death for 15 to 24 years old (CDC, 2006). In 2004, there were approximately 144,000 deaths due to unintentional injuries in the US; 53% of which represent people over 45 years of age (CDC, 2004). With 20,322 suicidal deaths and 13,170 homicidal deaths, intentional injury deaths affect mostly people under 45 years old. On average, there are 1,150 unintentional deaths per year in Iowa. In 2004, 37% of unintentional deaths were due to motor vehicle accidents (MTVCC) occurring across all age ranges and 30% were due to falls involving persons over 65 years of age 82% of the time (IDPH Health Stat Div., 2004). The most debilitating outcome of injury is traumatic brain injury, which is characterized by the irreversibility of its damages, long-term effects on quality of life, and healthcare costs. The latest data available from the CDC estimated that, nationally, 50,000 traumatic brain injured (TBI) people die each year; three times as many are hospitalized and more than twenty times as many are released from emergency room (ER) departments (CDC, 2006). Besides the TBI registry, brain injury data is also captured through three other data sources: 1) death certificates; 2) hospital inpatient data; and, 3) hospital outpatient data. The inpatient and outpatient hospital data are managed by the Iowa Hospital Association, which provides to Iowa Department of Public Health the hospital data without personal identifiers. (The hospitals send reports to the Agency of Health Care Research and Quality, which developed the Health Care Utilization Project and its product, the National Inpatient Sample).

Field Performance and Evaluation of Slurry Seals, HR-195, 1980

As part of the overall research program of evaluating asphalt emulsion slurry seal as a pavement maintenance material, 31 duplicate 500-ft test sections were constructed on U.S. 6 between Adel and Waukee in Dallas County during September and October of 1978. These test sections included combinations of eight aggregates, two gradings, three asphalt emulsions, two mineral fillers, and a range of emulsion contents determined by laboratory mix designs. The emulsion contents of the test sections varied from 10.3% for Section 7A (Ferguson coarse) to 32.9% for Section 31A (lightweight aggregate). The post-construction performance evaluation of the test sections, consisting primarily of the friction tests and surface appearance observations, was conducted at different time intervals up to 24 months after construction. At the 24-month final evaluation, most of the test sections had carried a total of 1.4 million vehicles.

Impact of Left-Turn Phasing on Older and Younger Drivers at High-Speed Signalized Intersections, 2004

Several recent studies have demonstrated differences in safety between different types of left-turn phasing—protected, permitted, and protected/permitted phasing. The issue in question is whether older and younger drivers are more affected by a particular type of left-turn phasing at high-speed signalized intersections and whether they are more likely to contribute to a left-turn related crash under a specific type of left-turn phasing. This study evaluated the impact of different types of left-turn phasing on older and younger drivers at high-speed signalized intersections in Iowa. High-speed signalized intersections were of interest since oncoming speeds and appropriate gaps may be more difficult to judge for older drivers and those with less experience. A total of 101 intersections from various urban locations in Iowa with at least one intersecting roadway with a posted speed limit of 45 mph or higher were evaluated. Left-turn related crashes from 2001 to 2003 were evaluated. Left-turn crash rate and severity for young drivers (14- to 24-year-old), middle-age drivers (25- to 64-year-old), and older drivers (65 years and older) were calculated. Poisson regression was used to analyze left-turn crash rates by age group and type of phasing. Overall, left-turn crash rates indicated that protected phasing is much safer than protected/permitted and permitted phasing. Protected/permitted phasing had the highest left-turn crash rates overall.