1st Avenue Improvements

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

1st Avenue between 6th Street and 9th Street began total reconstruction in 2018 and finished in 2019. This was the final section of 1st Avenue to be improved south of Interstate 80.

Highlights

Reconstruction on this stretch of 1st Avenue featured:

Four through lanes and one continuous center turn lane
10 foot wide sidewalks and brick paver treatments on both sides
Upgraded traffic signals at E. 7th Street
Northbound 1st Avenue right turn lane onto 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
Railroad crossing signals and gates at 1st Avenue & 6th Street
New public utilities (storm sewer, sanitary sewer, and water main)
Lighting and streetscaping, including trees

Cost
Timeline
Resources
Videos

Pre-Project Planning

Duct Banks

In anticipation of the project, underground duct banks were 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 minimized delays caused by private utility relocations, which can be common during street projects.

How We Keep Traffic Moving

To reduce traffic delays during construction:

Staff monitored traffic times and adjusted 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

Merging Traffic

How to Merge Efficiently on 1st Avenue during Construction

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"

Watch for signs giving drivers notice that there is a merge ahead
Stay in your lane up to the point of merge
Take turns with drivers to safely ease into the remaining lane
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

Alberta Motor Association: "Zipper Merge Demonstration" (YouTube)
Kansas DOT: "How to Zipper Merge" (YouTube)
Minnesota DOT: "Zipper Merge Camera Traffic Instructional" (YouTube)

Stay Informed

Sign up for e-news alerts ("Construction and Traffic Updates" category)
Like City of Coralville, Iowa on Facebook
Follow the City of Coralville, Iowa on Twitter
Join Nextdoor (a private social network for Coralville neighborhoods)
Pay attention to construction message boards along 1st Avenue during construction
Check local news for media releases
Attend weekly meetings April-June 2019 with the City and the contractors, and open to the public: