Iowa Uniform Crime Report, Iowa Department of Public Safety, 1999

If it comes to the attention of a sheriff, police department or other law enforcement agency that a public offense has been committed in its jurisdiction, the law enforcement agency shall report information concerning such a public offense to the department on a form to be furnished by the department not more than thirty-five days from the time the public offense first comes to the attention of the law enforcement agency. The reports shall be used to generate crime statistics. The department shall submit statistics to the governor, the general assembly, and the division of criminal and juvenile justice planning of the department of human rights on a quarterly and yearly basis.

Iowa Uniform Crime Report, Iowa Department of Public Safety, 2000

If it comes to the attention of a sheriff, police department or other law enforcement agency that a public offense has been committed in its jurisdiction, the law enforcement agency shall report information concerning such a public offense to the department on a form to be furnished by the department not more than thirty-five days from the time the public offense first comes to the attention of the law enforcement agency. The reports shall be used to generate crime statistics. The department shall submit statistics to the governor, the general assembly, and the division of criminal and juvenile justice planning of the department of human rights on a quarterly and yearly basis.

Iowa Uniform Crime Report, Iowa Department of Public Safety, 2002

If it comes to the attention of a sheriff, police department or other law enforcement agency that a public offense has been committed in its jurisdiction, the law enforcement agency shall report information concerning such a public offense to the department on a form to be furnished by the department not more than thirty-five days from the time the public offense first comes to the attention of the law enforcement agency. The reports shall be used to generate crime statistics. The department shall submit statistics to the governor, the general assembly, and the division of criminal and juvenile justice planning of the department of human rights on a quarterly and yearly basis.

Guidleines for Removal of Traffic Control Devices in Rural Areas, October 2005

It is commonly regarded that the overuse of traffic control devices desensitizes drivers and leads to disrespect, especially for low-volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer’s (ITE) Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approach(es) to stop is left to engineering judgment and is usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume itself is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer (or perhaps never) met engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop-controlled intersections. The scope of this research is ultra-low-volume (< 150 daily entering vehicles) unpaved intersections in rural agricultural areas of Iowa, where each of the 99 counties may have as many as 300 or more STOP sign pairs. Overall safety performance is examined as a function of a county excessive use factor, developed specifically for this study and based on various volume ranges and terrain as a proxy for sight distance. Four conclusions are supported: (1) there is no statistical difference in the safety performance of ultra-low-volume stop-controlled and uncontrolled intersections for all drivers or for younger and older drivers (although interestingly, older drivers are underrepresented at both types of intersections); (2) compliance with stop control (as indicated by crash performance) does not appear to be affected by the use or excessive use of STOP signs, even when adjusted for volume and a sight distance proxy; (3) crash performance does not appear to be improved by the liberal use of stop control; (4) safety performance of uncontrolled intersections appears to decline relative to stop-controlled intersections above about 150 daily entering vehicles. Subject to adequate sight distance, traffic professionals may wish to consider removal of control below this threshold. The report concludes with a section on methods and legal considerations for safe removal of stop control.

Volume of Traffic on the Primary Road System, 2002

The Office of Transportation Data, in cooperation with the Federal Highway Administration, prepares this biennial traffic report. This report is used by federal, state, and local governmental agencies in determining highway needs, construction priorities, route location and environmental impact studies, and the application of appropriate design standards. The general public uses this information in determining the amount of traffic that passes a given area as they make their development plans and propose land use changes. The above reflects only a few of the many technical uses for this data.

Iowa Highway Safety Program, Iowa Department of Public Safety, 2008

Annual Highway Safety Report for Iowa Department of Public Safety.

Iowa Highway Safety Program, Iowa Department of Public Safety, 2009

Annual Highway Safety Report for Iowa Department of Public Safety.

Safety and Mobility Impacts of Winter Weather – Phase I, August 2011

Highway agencies spend millions of dollars to ensure safe and efficient winter travel. However, the effectiveness of winter weather maintenance practices on safety and mobility are somewhat difficult to quantify. Phase I of this project investigated opportunities for improving traffic safety on state-maintained roads in Iowa during winter weather conditions. The primary objective was to develop several preliminary means for the Iowa Department of Transportation (DOT) to identify locations of possible interest systematically with respect to winter weather-related safety performance based on crash history. Specifically, metrics were developed to assist in identifying possible habitual, winter weather-related crash sites on state-maintained rural highways in Iowa. In addition, the current state of practice, for both domestic and international highway agency practices, regarding integration of traffic safety- and mobility-related data in winter maintenance activities and performance measures were investigated. This investigation also included previous research efforts. Finally, a preliminary work plan, focusing on systematic use of safety-related data in support of winter maintenance activities and site evaluation, was prepared.

Temporary Traffic Control and Enforcement of Traffic Laws in Closed Road Sections, June 2007

Public travel by motor vehicles is often necessary in road and street sections that have been officially closed for construction, repair, and/or other reasons. This authorization is permitted in order to provide access to homes and businesses located beyond the point of closure. The MUTCD does address appropriate use of specific regulatory signs at the entrance to closed sections; however, direct guidance for temporary traffic control measures within these areas is not included but may be needed. Interpretation and enforcement of common practices may vary among transportation agencies. For example, some law enforcement officers in Iowa have indicated a concern regarding enforcement and jurisdiction of traffic laws in these areas because the Code of Iowa only appears to address violations on roadways open to “public travel.” Enforcement of traffic laws in closed road sections is desirable to maintain safety for workers and for specifically authorized road users. In addition, occasional unauthorized entry by motor vehicles is experienced in closed road areas causing property damage. Citations beyond simple trespass may be advisable to provide better security for construction sites, reduce economic losses from damage to completed work, and create safer work zones.

Improving Traffic Safety Culture in Iowa – Phase II, July 2013

Phase II of Improving Traffic Safety Culture in Iowa focuses on producing actions that will improve the traffic safety culture across the state, and involves collaboration among the three large public universities in Iowa: Iowa State University, University of Northern Iowa, and University of Iowa. More specifically, this second phase synthesizes the expert opinions solicited in Phase I with prevailing public views and/or opinions gathered from a follow-up survey on Iowa’s 2000 public opinion survey, which the University of Northern Iowa, Center for Social and Behavioral Research, administered. More recent data on the opinions of Iowans and of people nationally contrasted with past data will help better define the public’s position on top safety culture issues. This, in turn, will provide a better basis for developing actionable, fundable, and ultimately successful strategies that will make a tangible difference in improving traffic safety in Iowa.

Calibration of Highway Safety Manual Work Zone Crash Modification Factors, TPF-5(081), 2014

The Highway Safety Manual is the national safety manual that provides quantitative methods for analyzing highway safety. The HSM presents crash modification factors related to work zone characteristics such as work zone duration and length. These crash modification factors were based on high-impact work zones in California. Therefore there was a need to use work zone and safety data from the Midwest to calibrate these crash modification factors for use in the Midwest. Almost 11,000 Missouri freeway work zones were analyzed to derive a representative and stratified sample of 162 work zones. The 162 work zones was more than four times the number of work zones used in the HSM. This dataset was used for modeling and testing crash modification factors applicable to the Midwest. The dataset contained work zones ranging from 0.76 mile to 9.24 miles and with durations from 16 days to 590 days. A combined fatal/injury/non-injury model produced a R2 fit of 0.9079 and a prediction slope of 0.963. The resulting crash modification factors of 1.01 for duration and 0.58 for length were smaller than the values in the HSM. Two practical application examples illustrate the use of the crash modification factors for comparing alternate work zone setups.

Improving Traffic Safety Culture in Iowa, 2011

Vehicle crashes rank among the leading causes of death in the United States. In 2006, the AAA Foundation for Traffic Safety “made a long- term commitment to address the safety culture of the United States, as it relates to traffic safety, by launching a sustained research and educational outreach initiative.” An initiative to produce a culture of safety in Iowa includes the Iowa Comprehensive Highway Safety Plan (CHSP). The Iowa CHSP “engages diverse safety stakeholders and charts the course for the state, bringing to bear sound science and the power of shared community values to change the culture and achieve a standard of safer travel for our citizens.” Despite the state’s ongoing efforts toward highway safety, an average of 445 deaths and thousands of injuries occur on Iowa’s public roads each year. As such, a need exists to revisit the concept of safety culture from a diverse, multi-disciplinary perspective in an effort to improve traffic safety. This study summarizes the best practices and effective laws in improving safety culture in the United States and abroad. Additionally, this study solicited the opinions of experts in public health, education, law enforcement, public policy, social psychology, safety advocacy, and traffic safety engineering in a bid to assess the traffic safety culture initiatives in Iowa. Recommendations for improving traffic safety culture are offered in line with the top five Iowa CHSP safety policy strategies, which are young drivers, occupant protection, motorcycle safety, traffic safety enforcement and traffic safety improvement program, as well as the eight safety program strategies outlined in the CHSP. As a result of this study, eleven high-level goals were developed, each with specific actions to support its success. The goals are: improve emergency medical services response, toughen law enforcement and prosecution, increase safety belt use, reduce speeding-related crashes, reduce alcohol-related crashes, improve commercial vehicle safety, improve motorcycle safety, improve young driver education, improve older driver safety, strengthen teenage licensing process, and reduce distracted driving.

Guidelines for Removal of Traffic Control Devices in Rural Areas, TR-527, 2005

It is commonly regarded that the overuse of traffic control devices desensitizes drivers and leads to disrespect, especially for low-volume secondary roads with limited enforcement. The maintenance of traffic signs is also a tort liability concern, exacerbated by unnecessary signs. The Federal Highway Administration’s (FHWA) Manual on Uniform Traffic Control Devices (MUTCD) and the Institute of Transportation Engineer’s (ITE) Traffic Control Devices Handbook provide guidance for the implementation of STOP signs based on expected compliance with right-of-way rules, provision of through traffic flow, context (proximity to other controlled intersections), speed, sight distance, and crash history. The approach(es) to stop is left to engineering judgment and is usually dependent on traffic volume or functional class/continuity of system. Although presently being considered by the National Committee on Traffic Control Devices, traffic volume itself is not given as a criterion for implementation in the MUTCD. STOP signs have been installed at many locations for various reasons which no longer (or perhaps never) met engineering needs. If in fact the presence of STOP signs does not increase safety, removal should be considered. To date, however, no guidance exists for the removal of STOP signs at two-way stop-controlled intersections. The scope of this research is ultra-low-volume (< 150 daily entering vehicles) unpaved intersections in rural agricultural areas of Iowa, where each of the 99 counties may have as many as 300 or more STOP sign pairs. Overall safety performance is examined as a function of a county excessive use factor, developed specifically for this study and based on various volume ranges and terrain as a proxy for sight distance. Four conclusions are supported: (1) there is no statistical difference in the safety performance of ultra-low-volume stop-controlled and uncontrolled intersections for all drivers or for younger and older drivers (although interestingly, older drivers are underrepresented at both types of intersections); (2) compliance with stop control (as indicated by crash performance) does not appear to be affected by the use or excessive use of STOP signs, even when adjusted for volume and a sight distance proxy; (3) crash performance does not appear to be improved by the liberal use of stop control; (4) safety performance of uncontrolled intersections appears to decline relative to stop-controlled intersections above about 150 daily entering vehicles. Subject to adequate sight distance, traffic professionals may wish to consider removal of control below this threshold. The report concludes with a section on methods and legal considerations for safe removal of stop control.

Synthesis of Traffic Calming Techniques in Work Zones, 2009

Nationwide, over 1,000 fatalities and 40,000 injuries occur annually in work zones, which include both construction zones and areas where maintenance is performed. The majority (85%) of work zone accidents result from unsafe driver behavior, and vehicle speed is often a factor in work zone crashes. In order to address speed and driver behavior near work zones, roadway agencies have developed different traffic calming measures. The objective of this research is to summarize the effectiveness of different traffic calming treatments for reducing speeds in work zones. This project 1. identified work zone traffic calming treatments for which information has not been well summarized, 2. identified state of the art and new technologies for work zone traffic calming, and 3. synthesized research related to items 1 and 2

Effectiveness of Roadway Safety Improvements, 2001

The Iowa Department of Transportation (DOT) continuously assesses the likely causes of crashes at high-crash locations throughout the Iowa roadway network and designs solutions to reduce the incidences of crashes. This research analyzed approximately 100 safety projects constructed in the past 10 years to see what affect they had on highway safety. The projects are grouped into seven categories as defined by their scope of work: (1) install new traffic signal, (2) add turn lane(s), (3) install new signal and turn lane(s), (4) add left-turn phasing, (5) add left-turn phasing and turn lane(s), (6) replace pedestal mount signals with mast arm signals, and (7) other geometric improvements. The project makes use of an extensive statewide crash database. The results of the project will evaluate the assumed reduction factors and benefit/cost (B/C) analysis, determine the actual cost effectiveness of the Iowa DOT's safety programs, and allow the Iowa DOT to better prioritize future improvements.