The last piece of new bridge deck has finally been installed on the Pulaski Skyway, but there's more work left to do before the 3.5 mile bridge between Newark and Jersey City can be reopened to two-way traffic this spring, state Department of Transportation officials said.

The northbound Skyway was closed in April 2014 for a $1 billion rehabilitation project, which has been dogged by delays blamed on a severe winter and the discovery of corroded cross beams under the road surface that had to be replaced. Those and other problems resulted in the schedule to reopen the skyway being pushed back three times.

Most recently, DOT officials said in April that a planned summer 2017 reopening date would be missed because officials wanted to replace retaining walls on Route 139, which is the highway that feeds traffic to the Skyway.

The retaining walls were not part of the original $1 billion Skyway rehabilitation project. Now, only one side of the Skyway is open to southbound traffic. That traffic is currently using the reconstructed northbound lanes.

Drivers who've diverted to the northbound New Jersey Turnpike Hudson County extension for the last several years have complained about the pace of the project and asked when it will reopen. The New Jersey Turnpike Authority also has delayed major construction for the extension until the Skyway is reopened.

While the last bridge deck panel was installed in early December, there is "still a good deal of work to be completed before the Skyway can open to two-way traffic," said Stephen Schapiro, NJDOT spokesman. Officials are still sticking to a reopening date sometime in the spring, he said.

Commuters driving south on the Skyway can see that a fair amount of concrete work remains to be done. That includes pouring concrete in the gap between the northbound and southbound lanes and fabricating a new median between the lanes, Schapiro said.

A sidewalk on the southbound side of the Skyway has just been completed, which allows crews to install a decorative balustrade, he said. Once that work is finished, the guide rail on the southbound side of the Skyway can be bolted in place, he said.

There are 11 overhead sign structures and permanent highway lighting that has to be installed, in addition to drainage work that must be completed, Schapiro said. Before the Skyway is opened in both directions, temporary guide rails must be removed and new traffic lines have to be painted on the road, he said.

"All of this work is expected to be completed this spring, so the Skyway can reopen to two-way traffic," he said.

However, several entrance and exit ramps will remain closed after the full Skyway reopens, he said.

The exit ramp in Newark from the southbound Skyway to Raymond Boulevard; the Kearny entrance and exits and the Broadway northbound exit and entrance in Jersey City will all remain closed for rehabilitation, Schapiro said.

Larry Higgs may be reached at lhiggs@njadvancemedia.com. Follow him on Twitter @commutinglarry. Find NJ.com on Facebook.