The Minimum Safety Standard, Consumers’ Information, and Competition, February 2007

This paper explores the effects of a standard influencing care choice. Firm(s) may increase the probability of offering safe products by incurring a cost. Under duopoly, they compete either in prices or in quantities. Under perfect information about safety for consumers, the selected standard that corrects a safety underinvestment is always compatible with competition. Safety over investment only emerges under competition in quantities and relatively low values of the cost. Under imperfect information about safety for consumers, the standard leads to a monopoly situation. However, for relatively large values of the cost, a standard cannot impede the market failure coming from the lack of information.

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.

Audit report on applying agreed-upon procedures for the City of Linden’s compliance with road use tax requirements for the period July 1, 1999 through June 30, 2004

Audit report on applying agreed-upon procedures for the City of Linden’s compliance with road use tax requirements for the period July 1, 1999 through June 30, 2004

Iowa Department of Public Safety Agency Performance Plan, 2007

Agency Performance Plan

Audit report on Highway Safety Projects administered by The Integer Group Midwest for the year ended September 30, 2006

Audit report on Highway Safety Projects administered by The Integer Group Midwest for the year ended September 30, 2006

Audit report on the Iowa Department of Public Safety for the year ended June 30, 2006

Audit report on the Iowa Department of Public Safety for the year ended June 30, 2006

Safety Impacts of Pavement Edge Drop-offs, 2006

A vehicle may leave its travel lane for a number of reasons, such as driver error, poor surface conditions, or avoidance of a collision with another vehicle in the travel lane. When a vehicle leaves the travel lane, pavement edge drop-off poses a potential safety hazard because significant vertical differences between surfaces can affect vehicle stability and reduce a driver’s ability to handle the vehicle. Numerous controlled studies have tested driver response to encountering drop-offs under various conditions, including different speeds, vehicle types, drop-off height and shape, and tire scrubbing versus non-scrubbing conditions. The studies evaluated the drivers’ ability to return to and recover within their own travel lane after leaving the roadway and encountering a drop-off. Many of these studies, however, have used professional drivers as test subjects, so results may not always apply to the population of average drivers. Furthermore, test subjects are always briefed on what generally is to be expected and how to respond; thus, the sense of surprise that a truly naïve driver may experience upon realizing that one or two of his or her tires have just dropped off the edge of the pavement, is very likely diminished. Additionally, the studies were carried out under controlled conditions. The actual impact of pavement edge drop-off on drivers’ ability to recover safely once they leave the roadway, however, is not well understood under actual driving conditions. Additionally, little information is available that quantifies the number or severity of crashes that occur where pavement edge drop-off may have been a contributing factor. Without sufficient information about the frequency of edge drop-off-related crashes, agencies are not fully able to measure the economic benefits of investment decisions, evaluate the effectiveness of different treatments to mitigate edge drop-off, or focus maintenance resources. To address these issues, this report details research to quantify the contribution of pavement edge drop-off to crash frequency and severity. Additionally, the study evaluated federal and state guidance in sampling and addressing pavement edge drop-off and quantified the extent of pavement edge drop-off in two states. This study focused on rural two-lane paved roadways with unpaved shoulders, since they are often high speed facilities (55+ mph), have varying levels of maintenance, and are likely to be characterized by adverse roadway conditions such as narrow lanes or no shoulders.

Transfers, social safety nets and economic growth

The role of social safety nets in the form of redistributional transfersand wage subsidies is analyzed using a simple model of criminal behavior. Itis argued that public welfare programs act as a crime--preventing ordisruption--preventing devices because they tend to increase the opportunitycost of engaging in crime or disruptive activities. It is shown that, in thepresence of a leisure choice, wage subsidies may be better than pure transfers. Using a simple growth model, it is shown that it is not optimal for the governmentto try to fully eliminate crime. The optimal size of the public welfare programis found and it is argued that public welfare should be financed with income(not lump--sum) taxes, despite the fact that income taxes are distortionary.The intuition for this result is that income taxes act as a user fee oncongested public goods and transfers can be thought of as {\it productive}public goods {\it subject to congestion}. Finally, using a cross-section of 75 countries, the partial correlation betweentransfers and growth is shown to be significantly positive.

CrossRoads, Spring/Summer 2005; quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles

CrossRoads, Autumn 2006; quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety

Quarterly publication of the Governor's Traffic Safety Bureau, Iowa Department of Public Safety containing traffic safety and related information and news articles

Archaeology on the Road, July 2008

Team Archaeology is excited to be riding with you this year! We hope to make our participation an annual opportunity to share the story of Iowa’s amazing past. As you ride across the state you will be passing by the locations of hundreds of known archaeological sites and an as yet unknown number of new discoveries waiting to be made. These archaeological sites, and the artifacts they contain, tell the history of the first people to travel this landscape and the stories of each generation that has contributed to what we know of ourselves today. As you travel through our beautiful state, you too are now a part of that story, making history for the future to learn and wonder about! The Office of the State Archaeologist serves a unique dual role in Iowa as both a designated research unit of The University of Iowa and as a state agency. The larger mission of the OSA is to develop, disseminate, and preserve knowledge of Iowa’s human past through Midwestern and Plains archaeological research, scientific discovery, public stewardship, service, and education. It is our goal to provide all Iowans the opportunity to learn about their past. I see this as an investment in the preservation of a nonrenewable resource—the archaeological record of Iowa. Look for the Team Archeology members as you ride and be sure to ask them about Iowa archeology. Please help yourself to free materials about our shared past from our information tables at each overnight town and get one of the free Iowa Archeology wrist bands. There will also be free public talks by local archaeologists each afternoon, as well as flintknapping and other demonstrations of archaeological interest, so keep this booklet as your guide to the week’s activities. Most of all, ride smart, be safe, and when you get home tell your friends and neighbors about Iowa archaeology!

Report on the Iowa Department of Public Safety for the year ended June 30, 2007

Report on the Iowa Department of Public Safety for the year ended June 30, 2007