The Effect of Four-Lane to Three-Lane Conversion on the Number of Crashes and Crash Rates in Iowa Roads, June 2005

We analyze crash data collected by the Iowa Department of Transportation using Bayesian methods. The data set includes monthly crash numbers, estimated monthly traffic volumes, site length and other information collected at 30 paired sites in Iowa over more than 20 years during which an intervention experiment was set up. The intervention consisted in transforming 15 undivided road segments from four-lane to three lanes, while an additional 15 segments, thought to be comparable in terms of traffic safety-related characteristics were not converted. The main objective of this work is to find out whether the intervention reduces the number of crashes and the crash rates at the treated sites. We fitted a hierarchical Poisson regression model with a change-point to the number of monthly crashes per mile at each of the sites. Explanatory variables in the model included estimated monthly traffic volume, time, an indicator for intervention reflecting whether the site was a “treatment” or a “control” site, and various interactions. We accounted for seasonal effects in the number of crashes at a site by including smooth trigonometric functions with three different periods to reflect the four seasons of the year. A change-point at the month and year in which the intervention was completed for treated sites was also included. The number of crashes at a site can be thought to follow a Poisson distribution. To estimate the association between crashes and the explanatory variables, we used a log link function and added a random effect to account for overdispersion and for autocorrelation among observations obtained at the same site. We used proper but non-informative priors for all parameters in the model, and carried out all calculations using Markov chain Monte Carlo methods implemented in WinBUGS. We evaluated the effect of the four to three-lane conversion by comparing the expected number of crashes per year per mile during the years preceding the conversion and following the conversion for treatment and control sites. We estimated this difference using the observed traffic volumes at each site and also on a per 100,000,000 vehicles. We also conducted a prospective analysis to forecast the expected number of crashes per mile at each site in the study one year, three years and five years following the four to three-lane conversion. Posterior predictive distributions of the number of crashes, the crash rate and the percent reduction in crashes per mile were obtained for each site for the months of January and June one, three and five years after completion of the intervention. The model appears to fit the data well. We found that in most sites, the intervention was effective and reduced the number of crashes. Overall, and for the observed traffic volumes, the reduction in the expected number of crashes per year and mile at converted sites was 32.3% (31.4% to 33.5% with 95% probability) while at the control sites, the reduction was estimated to be 7.1% (5.7% to 8.2% with 95% probability). When the reduction in the expected number of crashes per year, mile and 100,000,000 AADT was computed, the estimates were 44.3% (43.9% to 44.6%) and 25.5% (24.6% to 26.0%) for converted and control sites, respectively. In both cases, the difference in the percent reduction in the expected number of crashes during the years following the conversion was significantly larger at converted sites than at control sites, even though the number of crashes appears to decline over time at all sites. Results indicate that the reduction in the expected number of sites per mile has a steeper negative slope at converted than at control sites. Consistent with this, the forecasted reduction in the number of crashes per year and mile during the years after completion of the conversion at converted sites is more pronounced than at control sites. Seasonal effects on the number of crashes have been well-documented. In this dataset, we found that, as expected, the expected number of monthly crashes per mile tends to be higher during winter months than during the rest of the year. Perhaps more interestingly, we found that there is an interaction between the four to three-lane conversion and season; the reduction in the number of crashes appears to be more pronounced during months, when the weather is nice than during other times of the year, even though a reduction was estimated for the entire year. Thus, it appears that the four to three-lane conversion, while effective year-round, is particularly effective in reducing the expected number of crashes in nice weather.

Iowa Autism Council By-Laws and Operating Procedures, Revised 2012

These By-laws and Operating Procedures are designed to guide the membership and work of the Iowa Autism Council. The Iowa Autism Council is a collaborative resource that envisions its role as an advocate for children and adults living with Autism Spectrum Disorder (autism and Asperger's and other conditions represented on the autism spectrum) and their families. As such, it is committed to representing individuals with diverse and changing educational needs. Iowa Autism Council (IAC) shall have, and will perform, functions and duties as specified by law. Responsibilities include offering advice, consultation, and recommendations to Governor Culver and the Iowa legislature regarding matters concerning the ASD population. The role of the Council members is to advise, not advocate, for an individual position. Advise means to inform, counsel, recommend, suggest or guide. To advocate means to plead for your case or position, to favor an individual case or argument. The advisory Council is to provide advice, based on facts and good judgment.

Executive Order Number Seventeen, September 25, 2009

This Executive Order expects the State of Iowa executive agencies and Regent Institutions own, purchase, build and lease property, including office space, worth billions of dollars for educational, correctional, recreational, conservation, transportation, communication, public health, workforce and related public functions and the placement of state offices in historic central business districts "downtown" can strengthen and revitalize Iowa's cities and towns.

The History of the Establishment of the Division of Child Welfare of the Social Welfare Department of the State of Iowa, 1938

History of Child Welfare Legislation in the State of Iowa 1838-1898; Establishment of the Iowa State board of Control in 1898 and its influence on Child Welfare Legislation until 1925; Immediate background, organizing and the administration functions of the Child Welfare Division of the Social Welfare Department of the State of Iowa. NOTE: This document has pagination errors.

Report of the Iowa Attorney General, 2003-2004.

Biennial report of the Attorney General of the state of Iowa. Lists the past Attorney General's of Iowa. Lists the personnel in the office and describes the functions of each division in 2003-2004. Includes summaries of opinions issued 2003-2004.