The Effects of Interstate Speed Limit Increases: Fatality Rates and Traffic Diversion Versus Speed Spillover

This thesis examines two panel data sets of 48 states from 1981 to 2009 and utilizes ordinary least squares (OLS) and fixed effects models to explore the relationship between rural Interstate speed limits and fatality rates and whether rural Interstate speed limits affect non-Interstate safety. Models provide evidence that rural Interstate speed limits higher than 55 MPH lead to higher fatality rates on rural Interstates though this effect is somewhat tempered by reductions in fatality rates for roads other than rural Interstates. These results provide some but not unanimous support for the traffic diversion hypothesis that rural Interstate speed limit increases lead to decreases in fatality rates of other roads. To the author’s knowledge, this paper is the first econometric study to differentiate between the effects of 70 MPH speed limits and speed limits above 70 MPH on fatality rates using a multi-state data set. Considering both rural Interstates and other roads, rural Interstate speed limit increases above 55 MPH are responsible for 39,700 net fatalities, 4.1 percent of total fatalities from 1987, the year limits were first raised, to 2009.

Risk Factors for Physical Restraint Use in Nursing Homes: The Impact of the Nursing Home Reform Act

This study examined the impact of the Nursing Home Reform Act of 1987 on resident-and-facility-level risk factors for physical restraint use in nursing homes. Data on the 1990 and 1993 cohorts were obtained from 268 facilities in 10 states, and data on a 1996 cohort were obtained from the Medical Expenditure Panel Survey, which sampled more than 800 nursing homes nationwide. Multivariate logistic regression models were generated for each cohort to identify the impact of resident- and facility-level risk factors for restraint use. The results indicate that the use of physical restraints continues to decline. Thirty-six percent of the 1990 cohort, 26 percent of the 1993 cohort, and 17 percent of the 1996 cohort were physically restrained. Although there was a reduced rate of restraint use from 1990 to 1996, similar resident-level factors but different facility-level factors were associated with restraint use at different points in time.