First transcontinental interstate

[texaskdog]

What was the first Interstate highway E-W completed across the country?

I should know this....

[21stCenturyRoad]

I-80. The final segment opened just west of Salt Lake City in 1986.

[jon daly]

I-80. The final segment opened just west of Salt Lake City in 1986.

Wow. I would've guessed that one would've been completed before then.

[texaskdog]

I-80. The final segment opened just west of Salt Lake City in 1986.

at Promontory point?

[sparker]

The '86 completion date would make I-80 the first of the three "true" transcontinentals to be done.  IIRC, I-90's last section in Wallace, ID was completed circa '91 (please correct me if I'm mistaken), while I-10 through downtown Phoenix was opened at about the same time.  Now -- if a case can be made to include I-40 in the mix (horseshoe rules, where "leaners" count for something!) -- the completion of the Raleigh-Wilmington stretch in the early '90's would complete it at about the time I-10 and I-90 reached fruition as well -- but I-80's completion still does precede all the rest.

[Bruce]

The last segment in Idaho to open was a stretch approaching Coeur d'Alene in 1992, according to this article.

The Seattle-Bellevue section wasn't fully complete until the Lacey V. Murrow floating bridge was reopened in 1993.

[US 89]

I-80. The final segment opened just west of Salt Lake City in 1986.

at Promontory point?

No. The original transcontinental railroad did not follow I-80 west of Echo, UT. It followed I-84 into Ogden and then went around the north end of the Great Salt Lake, before rejoining the modern I-80 corridor in eastern Nevada. The rails were joined at a place called Promontory Summit, where for a time there was a railroad town called Promontory. (Minor nitpick: Promontory Point is actually the name for the southern tip of the peninsula that splits the northern half of the Great Salt Lake, which was not on the original railroad.) Much of the original route has been scrapped because it was bypassed by the railroad causeway directly across the lake, which was completed in 1904. This means that today, there is indeed a railroad line through Promontory Point.

And to be more specific, the final segment of I-80 to be completed was the 4.5 mile segment between 5600 West and Redwood Rd, on the west side of Salt Lake City. I believe the pavement on that section today dates from 1986, and until last summer much of the original signage was still up.

[Chris]

I-10 had that gap at Downtown Phoenix, but I-17 was completed around Downtown in 1963-1965, meaning virtually no detour for through traffic. I wonder when it was first possible to drive from Los Angeles to Jacksonville via a more-or-less direct freeway route. Perhaps 1983, when the Fort Stockton bypass opened to traffic?

[NE2]

If I-84 (west) was complete before I-80, that would have provided a full transcontinental route.

[US 89]

If I-84 (west) was complete before I-80, that would have provided a full transcontinental route.

The same would be true if I-15 was complete south of Salt Lake City before 1986, since it connects to Southern California. I don't know when 15 was completed in Utah or California, but the AZ and NV sections were finished in the 1970s.

[TheArkansasRoadgeek]

Wow! I knew there must've been others, but I would've guessed I-40 as being a grandfather of transcontinental Interstates.


iPhone

[SSOWorld]

Wow! I knew there must've been others, but I would've guessed I-40 as being a grandfather of transcontinental Interstates.


iPhone

Only if it continued further west.

[kkt]

I-80. The final segment opened just west of Salt Lake City in 1986.

at Promontory point?