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GIS Graduate Seminars: Bijan Vafaei & Steven Younkin

April 17, 2017 @ 12:10 pm - 1:30 pm

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Installation Guidance for Centerline and Edgeline Rumble Strips in Narrow Pavements

Bijan Vafaei, GIS Certificate Candidate, Department of Civil Construction and Environmental Engineering

Advisor: Dr. Peter Savolainen


Rumble strips on two-lane rural highways are proven safety countermeasures. Placement rumble strips can usually be accommodated within wide pavements (24 ft or greater paved width) without issue. However, proper placement is less straightforward for highways with paved widths less than 24 ft. Contributing factors such as traffic volume, and roadway alignment may suggest the use of one type of rumble strip over another. This study involved an analysis of historical crash data for segments with and without rumble strip in order to assess the risk of cross-centerline and run-off-road crashes in Iowa. The research involved a series of GIS programming and automation in Python including spatial analysis, geoprocessing, and map processing to accelerate the process of data preparation, modeling and analysis. To assess the Iowa-specific effects of rumble strip installations, a data set was constructed for the two-lane, two-way primary highway network. The ultimate purpose of this study is to provide guidance based on safety analysis to assist county road agencies, as well as the Iowa Department of Transportation (DOT), in determining when to install rumble strips or and which of the two to install when the installation of both is not feasible based on various site-specific factors.

Engaging Stakeholders in Intersection Traffic Safety in Iowa

Steven Younkin, GIS Certificate Candidate, Department of Civil Construction and Environmental Engineering

Engaging Stakeholders in Intersection Traffic Safety in Iowa


Out of the 54,589 crashes in Iowa in 2015, 34% of these occurred at intersections. In order to better address safety issues, researchers have established a clear multiple regression methodology for predicting crashes based on intersection attributes. Mature crash and intersection databases are currently available along with traffic volumes for utilization as variables in a multiple regression negative binomial model. The main purpose of this project is to develop a webmapping tool to analyze which intersections are safer or more dangerous than similar intersections in different jurisdictions as well as compare within jurisdictions to find the sites with top potential for improvement. Applications used to develop this will be ArcMap for near analysis combining traffic data to intersection database, R for statistical modeling and several leaflet/javascript webmapping libraries to cluster map data, filter queries, and produce charts and figures in a responsive and user friendly environment. This tool should allow city managers, county engineers, and other stakeholders to make better decisions with available funds and improve engagement with the public in their decision making process.

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April 17, 2017
12:10 pm - 1:30 pm
Event Category:


526 Design
715 Bissell Road
Ames, IA 50011 United States
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