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Iowa in Motion 2045 – connecting the dots to improve the transportation system

12/22/2016

IA-Motion_horizontal_color-gradient.fwWith the holiday season upon us, we can take for granted how easily all those gifts and goodies get to stores and even directly to our doorsteps. Just because our transportation system is good, that doesn’t mean it can’t be better. Developing and maintaining a system for the efficient movement of people and goods is the core task of the Iowa Transportation Commission and the Iowa Department of Transportation. Making sure the transportation system is improved in the right places at the right time takes a lot of planning behind the scenes year-round.

As part of the Iowa Transportation Commission and Iowa DOT’s long-term planning effort, Iowa in Motion 2045, several planning efforts are being connected together to get an overall picture of how the transportation system is functioning and where there is room for improvement. To make a good system better, Iowa DOT planners are collecting and analyzing data in new and innovative ways.

As you may have read in a previous post, several layers of analysis are being conducted for the highway system. For this post, we’ll look at two supporting highway planning efforts and how they fit into the long-range plan: the Iowa State Freight Plan and the condition of the state’s Primary Highway System based on the Infrastructure Condition Evaluation (ICE) tool.

Freight and condition graphicBack in July 2016, the Iowa DOT finalized the Iowa State Freight Plan. The purpose of the plan focused on studying freight-related data to identify improvements for Iowa’s transportation system to address needs of goods moved by air, truck, pipeline, rail, and water.

Since Iowa sits in the center of the country, a large quantity of the goods transported both cross-country and to other nations either start or end here or pass through our state. Working collaboratively within the Iowa DOT and with public/private stakeholders, the Iowa State Freight Plan was developed to investigate major trends and issues impacting freight movements in Iowa. The planning effort also identified freight bottlenecks, or places on the system that efficient freight movement may be hindered.

Andrea White, with the Iowa DOT’s Office of Systems Planning, said, “Iowa is unique in that we use many different data sources, including real-time traffic data and input from our local partners in the metropolitan planning organizations and regional planning affiliations, to identify and map areas where freight isn’t moving as smoothly as we would like.”

The Iowa State Freight Plan identified and prioritized highway bottlenecks based on three factors: 1) data that showed how often freight traffic slowed significantly at each location; 2) an analysis of how the roadway network functions when each location cannot be used and traffic has to reroute; 3) and the condition of each location.

The ICE tool was used for the condition component with data utilized in the tool, including pavement condition ratings, international roughness values, bridge sufficiency ratings, average daily traffic counts, truck traffic counts, and the amount of congestion on a road segment. A total of 94 freight bottleneck locations across the state were identified and ranked through this process.

Bottleneck map
Map of 94 bottleneck locations identified in the analysis.
Freight table
Snapshot of the data used to create the map to the left.

 

 

 

 

 

 

 

 

In addition to being a component of the freight analysis, the condition of the overall highway system was also evaluated using the ICE tool. The shear amount of data can be overwhelming when you consider there are 27,141 highway segments being studied. To make the data more manageable, the segments were combined into 467 corridors. Each corridor was given an overall score by calculating a weighted average of the individual highway segments’ scores, which were based on the condition and traffic criteria mentioned earlier.

White notes that this is a great planning tool; however, since the highway corridors are made up of many segments, there may be small portions in good condition, but the overall corridor is in poor condition, or vice versa.

This analysis identified the bottom 25 percent of highway corridors in terms of condition. White commented, “This does not necessarily mean these roads are automatically selected to be revamped, as other factors also help determine when pavement and other improvements are made. But the analysis does help target overall corridors that are in less than ideal condition, which is an important consideration as projects are identified for development.”

Condition analysis

Our next post on Iowa in Motion 2045 will look at the remaining layers of highway analysis, which are urban capacity, bridges, and operations. White said, “The way we’re connecting layers of data analysis is a new and innovative effort as part of this long-range plan five-year update. Connecting information on the way the current highway system operates and areas where different types of needs exist helps us gain insight into possible improvements that would positively impact the way the transportation system as a whole functions. As planners, we’re very optimistic the long-term goals we’re setting with this effort will be the most effective way to keep people and goods moving around and through Iowa for many years to come.”


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Iowa highway in the evening