Closing the final gap in the Interstate Highway System

The Interstate Highway System was begun in 1956 after being authorized by President Dwight D. Eisenhower. Its original network was intended to be about 41 thousand miles in total length but currently is closer to 48 thousand miles. The system will will likely never be 100% complete, as new segments and additions are being added to it all the time. But interestingly, there's one piece of the original 1956 network that still isn't complete, and it involves the busiest highway in the system:

Interstate 95, the country’s most used highway, will finally run as one continuous road between Miami and Maine by the late summer. The interstate’s infamous “gap” on the Pennsylvania and New Jersey border will be closed, turning I-95 into an unbroken river of concrete more than 1,900 miles long. In so doing, it will also mark a larger milestone, say transportation officials—the completion of the original United States interstate system.

Construction to fix the I-95 gap began more than eight years ago in Pennsylvania, but it has now reached its final stage. This week, the New Jersey Department of Transportation began switching out road signs in preparation for the change.

But I-95’s completion isn’t a standalone feat. Local transportation planners claim it will herald a larger accomplishment.

“The original Interstate Highway Act had a network of highways across the nation that were associated it. Through some federal bills since then, that list was amended a little bit and made a little bit larger—but our understanding is that this is the final piece of that original interstate system,” says Jay Roth, a consultant at Jacobs Engineering Group who has worked to close the gap in I-95 for more than two decades.

The "gap" in Interstate 95 is not obvious; it's actually a bit obscure and confusing:

If you are driving northbound on I-95, just outside of Princeton, a road sign will warn you that I-95 North—the road you are on—is ending. But the physical road itself doesn’t end—instead, the highway veers south, now under the name Interstate 295. If you don’t get off at an exit, you will find yourself suddenly driving south, and have to do a complicated series of maneuvers to get back on a northbound road.

On the other side of this gap, Interstate 95 continues northward, starting from eight miles away.

It all sounds confusing, and it is—I didn’t fully understand what was happening until I reported this story, and I grew up 10 minutes from this stretch of interstate.
But while the current situation may be perplexing, the root cause of the problem is easy to explain: There was supposed to be a chunk of highway in this part of New Jersey, and no one ever built it.

The missing piece of highway - the so-called "Somerset Highway" - was never built due to community opposition, rising gas prices and other factors. In lieu of the missing piece of highway, the fix for this piece of I-95 will be pretty simple: new direct connector ramps between I-95 and I-276 (the Pennsylvania Turnpike), and some re-designations of existing highways. 

While this closes the gap in I-95, not everyone thinks it's the ideal solution:

“They’ve needed an interchange between 95 and the Pennsylvania Turnpike. It’s good that they’ve done this,” said Kornhauser, the Princeton professor, of the project.

But he still lamented that the old Somerset Highway would still never get built.

Separating I-95 from the New Jersey Turnpike would have helped alleviate one of the Mid-Atlantic’s biggest design flaws, he said. The original plan to bridge the gap by hooking the Somerset Highway into Interstate 287, which forms a beltway around greater New York, would have allowed most interstate drivers to circumvent the city’s downtown.

Instead, I-95 now feeds into the George Washington Bridge, dumping drivers who would otherwise bypass the region into uptown Manhattan and the Cross Bronx Expressway.
“This is boring. This is really doing nothing,” he said of the plan. “This is really doing nothing to try to alleviate the pressure on the northern part of the New Jersey Turnpike and the George Washington Bridge.”

After looking at a map of the highway network in New Jersey and New York City, I can see that what Professor Kornhauser says makes sense. But it's clear that the Somerset Highway is never going to get off the drawing board it has spent the last six decades languishing on, so this is the next-best solution.

As the article notes, this project should be complete - and the gap in I-95 closed - late this summer.