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.

Correctional Industries preparing inmates for re-entry: Recidivism & post-release employment, September 30, 2005

Using a matched sample of 1091 inmates released between April 1,1999 and June 30, 2001, Prison Industries Enhancement Certification Program (PIECP) participants re-enter society more successfully than Traditional Industries (TI) or other than work (OTW) releasees in terms of employment. The primary findings of this research are that Iowa state prison inmates who worked in open-market jobs in PIECP were found to be significantly more successful in post-release employment. That is to say, they became tax-paying citizens quicker and remain in that status longer than TI and OTW releasees. Additionally, PIECP releasees were incarcerated post release at a slower rate than OTW releasees.

Crash Rates and Crash Densities on Secondary Roads in Iowa by Surface Type 2001 – 2009, July 6, 2010

Crash Rates and Crash Densities on Secondary Roads in Iowa by Surface Type produced by the Iowa Department of Transportation.

Crash Rates and Crash Densities on Secondary Roads in Iowa by Functional Class 2001 – 2009, July 6, 2010

Crash Rates and Crash Densities on Secondary Roads in Iowa by Functional Class produced by the Iowa Department of Transportation.

Historical Summary of Travel, Crashes, Fatalities, and Rates 1970 – 2009, July 6, 2010

Historical Summary of Travel, Crashes, Fatalities, and Rates 1970 – 2009, produced by Iowa Department of Transportation.

Historical Summary of Travel, Crashes, Fatalities, and Rates 2001 – 2009, July 6, 2010

Historical Summary of Travel, Crashes, Fatalities, and Rates 2001 – 2009, produced by Iowa Department of Transportation.

Moving On Moves Recidivism Rates Lower, Data Download, Iowa Department of Corrections, October 2009

The results of a recently conducted evaluation show that a gender-responsive program for women probationers holds promise in significantly reducing recidivism rates. The University of Cincinnati conducted the evaluation of the cognitive-behavioral program, Moving On, in which it compared recidivism outcomes for moderate to high-risk Iowa offenders completing the program with a similar group of offenders not having attended any cognitive program.

Recidivism of State FY96 Prison Releases in Iowa, May 2001

Expanding on research first presented in the Iowa Board of Parole FY99 Annual Report, this report presents recidivism data on offenders released from Iowa prisons during State FY1996 (July 1, 1995 – June 30, 1996). The figures presented here differ from those included in last year’s report due to four changes in the study. First, this year’s research includes data on those released from work release facilities, who were inadvertently omitted last year. In addition, the current figures include an additional year of tracking, as a second round of “rapsheets” was obtained to detect recidivism occurring within the last year.2 Also enhancing this year’s report is the availability of national recidivism data through the Interstate Identification Index (III). Further, while last year’s data looked only at the first new offense following release, this year’s study examines the most serious new conviction, resulting in higher felony recidivism rates. One note of caution should be voiced concerning the use of out-of-state records. A review of these records suggests very incomplete disposition reporting in III from some other states. In examining these records, it was not unusual to find a string of serious arrests with no dispositions noted. It was tempting in these situations to conclude that there must have been a conviction at some point, but we have resisted that urge when presenting figures on new convictions. This report is not intended to be an all-encompassing review of recidivism. Rather, it is meant to provide an illustration of the types of recidivism data available on prison releases in Iowa. Readers interested in other analyses of the data are urged to contact CJJP with suggestions and requests.

Iowa Department of Corrections, Strategic Plan 2014-2018, January 2014

Iowa’s adult correctional system carries out its legal mandate of protecting the public and promoting offender rehabilitation through a continuum of institution and community evidence based services and interventions. This continuum is designed with recognition that for most offenders, reentry planning starts upon admission to the corrections system. The effective and efficient management of offenders in accordance with their risk and criminogenic needs (those needs that contribute to criminality) is accomplished through targeted programming, release preparation, and transition services. Success in these endeavors assists offenders to become productive members of the community and makes it less likely that they will re-offend, resulting in lowered recidivism rates. In 1990 the Department’s prison recidivism rate was 44.7% and today it is 30.3%. Our overall desired outcome is to reduce the prison recidivism rate to 25% during the next five years by focusing resources toward our highest risk offenders.

Iowa Unemployment Rates by County, January 2014

Iowa Unemployment Rates by County map produced by the Iowa Workforce Development.

Unemployment Rates For Iowa Counties, March 2014

Iowa Unemployment Rates by County map produced by the Iowa Workforce Development.

Iowa Unemployment Rates by County, April 2014

Iowa Unemployment Rates by County map produced by the Iowa Workforce Development.

Modification of Ca-Montmorillonite by Low-Temperature Heat Treatment, HR-106, 1964

Objectives of this investigation were to measure the effects of moderate heat treatments (below the dehydroxylation temperature) on physical and chemical properties of a calcium-montmorillonite clay. Previous workers have noted the reduction in cation exchange capacity and swelling property after heating in the range 200 to 400°C, and have suggested several possible explanations, such as hysteresis effect, increased inter-layer attractions due to removal of inter-layer water, or changes in the disposition of inter-layer or layer surface ions. The liquid limits of Ca-montmorillonite were steadily decreased with increased temperature of treatment, levelling at about 450°C. The plastic limit decreased slightly up to 350°C, above which samples could no longer be rolled into threads. The gradual change is in contrast with sudden major changes noted for weight loss (maximum rates of change at l00°C and 500°C), glycol retention surface area (520°C), and d001 diffraction peak intensity (17.7 A spacing) and breadth after glycolation (530°C). Other properties showing more gradual reductions with heat treatment were amount of exchangeable calcium (without water soaking), cation exchange capacity by NH4AC method, and d001 intensity (21 A spacing) after storing at 100% r.h. one month and re-wetting with water. Previous water soaking allowed much greater release of fixed Ca++ up to 450°C. Similar results were obtained with cation exchange capacities when samples were treated with N CaCl2 solution. The 21.0 A peak intensity curve showed close similarity to the liquid limit and plastic index curves in the low temperature range, and an explanation is suggested.

Iowa Department of Corrections, Strategic Plan 2014-2018,

Iowa’s adult correctional system carries out its legal mandate of protecting the public and promoting offender rehabilitation through a continuum of institution and community evidence based services and interventions. This continuum is designed with recognition that for most offenders, reentry planning starts upon admission to the corrections system. The effective and efficient management of offenders in accordance with their risk and criminogenic needs (those needs that contribute to criminality) is accomplished through targeted programming, release preparation, and transition services. Success in these endeavors assists offenders to become productive members of the community and makes it less likely that they will re-offend, resulting in lowered recidivism rates. In 1990 the Department’s prison recidivism rate was 44.7% and today it is 30.3%. Our overall desired outcome is to reduce the prison recidivism rate to 25% during the next five years by focusing resources toward our highest risk offenders.

Iowa Unemployment Rates by County, July 2014

Iowa Unemployment Rates by County map produced by the Iowa Workforce Development.