New developments or changes in the use of an existing site can have an impact on traffic volumes and patterns on adjacent streets and highways.  These impacts can require intersection controls, additional lanes, or specified turn lanes to be installed prior to the development being approved and completed.  Jurisdictions (cities, counties, or the Iowa DOT) will often request that the Developer completed a Traffic Impact Letter (TIL) or a complete traffic study prior to issuing driveway permits or site plan approvals.  The CGA staff uses current traffic counts and specific information for each site to model trip generation and traffic impacts to surrounding roadways in order to determine the best solution.  Some of our recent projects include:


Unity Point Health, Marshalltown, Iowa:  This site began as a new clinic and is currently being expanded to a new full-service hospital along Highway 14 in Marshalltown.  CGA completed traffic counts, traffic modeling, and a full traffic study for the primary hospital entrance, a new secondary drive for use by ambulances, and a relocated access for an existing church.  The study results were incorporated into the final design of the hospital site with new turn lanes on Highway 14.

Cemstone Concrete Materials, Garner, Iowa:  This site is a new concrete plant along Highway 18 in Hancock County.  CGA assisted the client with a Traffic Impact Letter to the Iowa DOT to establish that additional modifications to Highway 18 were not warranted.  In addition to the TIL, CGA prepared new driveway plans and the required permits.

YSS Youth Rehabilitation Center, Story County, Iowa: Story County required a Traffic Impact Study along the gravel road accessing this new development in order to meet their requirements for a Conditional Use Permit.  CGA completed the study and assisted the developer and county with mitigation measures to lessen the impact the development would have on the surrounding landowners.

Horse Therapy Arena, Collins, Iowa:  Story County requested a Traffic Impact Letter for a new arena development to determine if additional traffic to the site would require dust control along this Farm to Market roadway.  CGA completed modeling and analysis of the site in order for the landowners to obtain a building permit.

Scooters, Iowa Falls, Iowa:  This new drive-thru coffee site is located in downtown Iowa Falls along Highway 65.  The Iowa DOT required a traffic impact study before approval of an entrance permit for the new site.  CGA completed modeling and analysis of the site in order to assist this long-standing client in obtaining a building permit for this site in a timely manner.