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Published July 13, 1998
Volume 6, Number 7



Flyover Project to Improve I-580/I-680 Interchange
 
580/680 Interchange
This model of the completed 580/680 flyover shows the new ramps, which should significantly increase traffic flow.



A major area freeway renovation begins this month as the I-580/680 direct connector project gets underway in Pleasanton and Dublin. The Alameda County Transportation Authority (ACTA), which funds and manages the project, marks the beginning of construction with a ground breaking ceremony on July 16. 

From Cloverleaf to Flyover
The most prominent feature of the project will be the construction of a direct connector or flyover ramp from southbound I-680 to eastbound I-580. 

"Right now, you have got basically a cloverleaf system: on all four quadrants there's a loop ramp where you go around in a big circle to merge onto the other freeway," says Francis Lo, a consultant and project manager for ACTA. "The ultimate plan is that everything will be a direct connector. You don't go through any loops, you just go on the flyover and boom, you're on the other side."

The upcoming work will provide for construction of a two-lane ramp to carry vehicles on southbound I-680 to eastbound I-580. 

"After this phase is done, there will still be three loops left," adds Lo. He anticipates the next flyover will connect westbound I-580 to southbound I-680. "That will cover traffic from the Central Valley going to Silicon Valley," he says. 

Only the southbound to eastbound connection has a construction timetable at this point.

Room to Merge
There are other enhancements which will be made as well. For instance, the current lane configuration for travellers from I-680 south to I-580 east provides just one lane. 

"The new ramp that we're going to provide is two lanes," says Lo. 

A separate lane is also planned for the exit to Hopyard Road from I-580. This will allow motorists travelling on the freeway to take the Hopyard exit without having to merge past vehicles just entering the freeway from I-680, which is the case now.

Additional On- and Off-Ramps
In addition to the flyover, several more on- and off-ramps will be added to the freeways. 

A new interchange serving southbound I-680 will be created at Amador Plaza Road. The construction of these ramps was the reason for the recent demolition of the Dublin Cinema. 

An on-ramp to northbound I-680 will also be added at Village Parkway. 

A Five-Year Project
The initial flyover project linking southbound I-680 with eastbound I-580 is expected to take up to five years to complete. 

While the heavy construction remains, there are several portions of the project that have been completed already, including soundwall construction and freeway widening. 

"The column that's in the middle of the BART tracks was done at the same time the tracks were installed, so we won't have to disrupt BART service when we construct this project." 

A Smooth Transition
ACTA's construction plans include mitigations to ensure that traffic disruptions are kept to a minimum. 

"We're going to look at how the work is going to impact traffic and mitigate that impact," Lo says. 

For example, all of the existing ramps will be retained during the construction process. Also, any construction necessitating freeway closures will occur at night. 

Starting in August, information will be available toll-free at (877) 4-580-680. 

"We're also working on putting up a web site with information about the project," says Lo. 

Lastly, a freeway service patrol will be deployed on a limited basis. This patrol will scour the freeway, helping motorists who need it. 
 
 



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