1st Avenue Improvements

1st Avenue Improvements: 6th Street to 9th Street

1st Avenue between 6th Street and 9th Street is undergoing total reconstruction in 2018. This is the final section of 1st Avenue that needs to be improved south of Interstate 80.


After work is complete, this stretch of 1st Avenue will feature:
  • Four through lanes and one continuous center turn lane
  • 10 foot wide sidewalks on both sides
  • Upgraded traffic signals at E. 7th Street
  • New traffic signals at 6th Street with a new four-leg intersection at 1st Avenue and 6th Street to accommodate a future connection of E. 2nd Avenue on the east leg
  • New public utilities (storm sewer, sanitary sewer, and water main)
  • Lighting and streetscaping
Finishing 1st logo


  • Bid in January 2018 IDOT letting
  • Low bid: $7,186,554.84 (Langman Construction of Rock Island, Illinois) 
  • Funding: $5.1 million of Surface Transportation Program funds, and local funds


  • Start: March 2018
  • Estimated completion: December 2018, weather permitting (driving lanes, sidewalks, and traffic signals)
  • Landscaping and final work: Spring 2019, weather permitting

Traffic Impact

  • There are traffic delays
  • Single lane traffic in both directions along 1st Avenue is maintained
  • Pedestrian access is maintained using temporary surfacing and channelizing barriers
  • Access to all businesses is maintained
  • 6th Street is closed between 1st Avenue and the Baymont Suites driveway from late April-mid August
  • The temporary traffic signals at the 1st Avenue/E. 7th Street intersection will be removed while E. 7th Street is closed and reconstructed
  • Temporary traffic signals will be installed in the summer of 2018 at the new 1st Avenue/6th Street/E. 2nd Avenue intersection. This signal will provide construction access to the new E. 2nd Avenue for the Iowa Arena/UIHC Phase 2 Clinic Projects. 

Public Transit Impact

  • Coralville Transit riders may experience delays on all routes, especially during peak traffic times. Any changes to routes and schedules will be posted on www.coralville.org/transit.

Contact Us

  1. Dan Holderness

    City Engineer

    Scott Larson

    Assistant City Engineer

    1512 7th St.
    P.O. Box 5127
    Coralville, IA  52241

    Ph: 319.248.1720
    Fx: 319.248.1894

    Staff Directory
1st Ave Construction Map 2018


Maps & Documents




Weekly job meetings are Thursdays at 9:00 am at City Hall, until further notice. The public is welcome to attend and participate.

Lane Closures/Traffic Changes

  • 1st Avenue traffic is reduced to one lane in both directions the entire length of the project, from 6th Street to 9th Street (see Resources: "Phase 2 - Stages 1 and 2").
  • 6th Street west of 1st Avenue is closed between 1st Avenue and the Baymont Inn & Suites driveway (see Phase 2 – Stage 1 in Resources: "Project map and construction phases"). Information about impacted Coralville Transit routes and stops is available at www.coralville.org/transit.
  • The inner left turn lane on eastbound 5th Street approaching 1st Avenue is closed to simplify the merging of 5th Street traffic turning left onto northbound 1st Avenue. 
  • E. 7th Street between 1st Avenue and E. 2nd Avenue is closed for total reconstruction. Use E. 9th Street to access the Iowa River Landing. A dedicated construction access road connected to 1st Avenue near the railroad crossing minimizes traffic impacts from the large redevelopment projects in the Iowa River Landing.
1st Ave lanes shifted east 04.26.18

Current & Upcoming Work*

Work completed the week of August 6:
  • Completed sanitary sewer main installation to the north end of the project (just south of Kum & Go driveway).
  • Storm sewer work has re-started, working to the north in front of Casa Azul.
  • Poured 75% of the sidewalk on the south side of 6th Street.
  • Poured concrete footings for 3 of the 6 roadway lights south of the railroad crossing. 
  • Temporary traffic signal pole set on the northwest corner of 1st Avenue & 6th Street in preparation for the next traffic control change. 
  • A majority of street paving is now complete within Phase 2 – Stage 1 (see image, blue boundary). The solid yellow areas show completed pavement as of August 9. The gaps between the street paving and the railroad crossing panels are scheduled to be filled with asphalt the week of August 13.  
1st Ave 6th St 08092018
  • Completed five of the seven storm intakes south of the railroad crossing. Most of the storm intakes on this project are similar to the intakes farther south on 1st Avenue (see image).  It’s a 3-step process to build each intake. A concrete box (roughly 5’ x 5’ x 5’ and open on the top) is set in the ground first. The box sits below the bottom of the street pavement and extends from back of curb out under the street.  The top is then formed and poured (yellow), followed by the throat (red).  
1st Ave Storm Intake Tops
Work expected the week of August 13:
  • Complete connection of new 12” water main under 1st Avenue to the existing 6” water main on E. 7th Street, and make the final connection between new and existing 12” water main on 1st Avenue just south of the Kum & Go driveway. 
  • Complete remaining temporary pavement connections within Phase 2 – Stage 1 that are needed to transition traffic onto the new 1st Avenue pavement during Phase 2 - Stage 2.
  • Continue backfilling behind new curbs south of the railroad crossing.  Grade for new sidewalk along north side of 6th Street. Form and pour new sidewalks where possible. 
  • Start placing brick pavers within crosswalks at 1st Avenue & 6th Street.
  • Install remaining street light and traffic signal pole bases south of the railroad crossing within Phase 2 – Stage 1.
  • Place modified subbase north of Pipeline Road to the southerly Days Inn driveway (skipping over McDonald’s driveway) and possibly pave this section later in the week. 
  • Complete storm sewer pipe installation along the westerly half of 1st Avenue north of the Pipeline Road and continue installing storm intakes and manholes.  The last storm intake structure along the west side of 1st Avenue is just south of Cantebury BP’s north driveway.  
Looking ahead:
  • Phase 2 – Stage 1 completion (re-opening of the 6th Street connection to 1st Avenue) is not expected to occur before the start of the Iowa City Community School District on August 23 and will most likely occur the week of August 27th.
    • We are continually monitoring progress to make sure adequate notification is provided to Coralville Transit, the school district, Durham School Services, and parents with students at nearby Central Elementary School.  
    • We will reassess the 6th Street opening date early the week of August 13 and we will send out a brief update on Tuesday afternoon, followed by the regular project update on Thursday afternoon. To sign up for details updates, contact slarson@coralville.org
  • Phase 2 – Stage 2 completion (completes the entire west half of 1st Ave) is scheduled for completion in mid-to-late September.  
*Updated August 9, 2018

Merging Traffic

How to Merge Efficiently on 1st Avenue

When traffic is slow and heavy, merging too early can create traffic backups. During peak traffic times on 1st Avenue, using a "zipper merge" can keep traffic moving and reduce traffic backups.

A "zipper merge" is when drivers use both lanes of traffic until they reach the defined merge area, and then alternate in "zipper" style into the open lane. This maximizes road space, reduces congestion, and allows both lanes to move at similar speeds.

How to "Zipper Merge"
  1. Watch for signs giving drivers notice that there is a merge ahead
  2. Stay in your lane up to the point of merge
  3. Take turns with drivers to safely ease into the remaining lane
  4. Always merge when it is safe

Merging FAQs

When is it best to use the zipper merge?

When traffic is congested and traveling at slower speeds, it is best to remain in your lane until the point where traffic can take turns merging, which is indicated by a "BEGIN MERGE" sign.

When is it best to merge early?
When traffic conditions are light and vehicles are traveling at highway speeds, it is best to merge as soon as safely possible.

Zipper Merge Resources

Take Turns sign

Pre-Project Planning

How We're Keeping Traffic Moving

To reduce traffic delays during construction:
  • Staff will monitor traffic times and adjust the timing of traffic signals as needed to help the traffic flow on 1st Avenue
  • Installed fiber optic communications at the 1st Avenue/E. 9th Street traffic signal
  • Installed pan/tilt/zoom cameras on 1st Avenue at both 5th Street and E. 9th Street, along with existing cameras at 1st Avenue/Highway 6, to remotely monitor traffic for the project corridor and beyond
  • Repositioned the traffic detection cameras at 1st Avenue/E. 9th Street to minimize false detections
  • Installed traffic detection cameras at the 1st Avenue/Interstate 80 traffic signals to replace the in-pavement traffic detection wire loops

Duct Bank NB Lane 062017

Duct Banks

In anticipation of the 
project, underground duct banks were proactively constructed in 2017. These duct banks provided places for the private utilities companies to relocate their overhead and underground facilities to be out of the way before the 2018 improvement projects. The duct banks should minimize delays caused by private utility relocations, which can be common during street projects.

Stay Informed

  1. 1st Avenue Construction Begins Next Phase on June 4

    1st Avenue will be reduced to one lane in each direction the entire length of the project, from just south of 6th Street to just south on 9th Street Read on...
  2. Coral Ridge Avenue Detour Begins

    Beginning Sunday evening, May 13, traffic will detour using Oakdale Boulevard, Crosspark Road, & Wheaton Road Read on...
  3. Traffic Control Modification at Oakdale Boulevard & Crosspark Road Intersection

    Begins Monday, April 23 Read on...
  1. 1st Avenue Construction Begins Next Phase on April 24

    6th Street to close between 1st Avenue and Baymont Inn & Suites driveway, 1st Avenue reduced to one lane in each direction near 6th Street intersection Read on...
  2. Construction to Begin on 1st Avenue from 6th Street to 9th Street

    Northbound 1st Avenue will be reduced to one lane from just south of 6th Street to just south of 9th Street Read on...
  3. Two Major Road Reconstruction Projects Begin This Spring

    Drivers should prepare for 1st Avenue & Coral Ridge Avenue road work Read on...
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