Comments on: Why Does Hawaii Have Interstate Highways?

By: K

Fri, 15 Aug 2008 20:08:33 +0000

Great info! I always wondered why there were so many I-*80’s in the Bay Area.

By: jeff

jeff — Fri, 15 Aug 2008 17:36:34 +0000

I-291 in Connecticut is the exception that proves two rules:

1) Two consecutive spurs or loops off the same interstate are not numbered identically: The CT I-291 is less than fifty miles from the next spur, I-291 in Springfield, MA, the closest identically numbered interstates in the country.

2) Odd numbered designations indicate a North-South intersatate: Orignally intended as a loop around Hartford, the project was mired in litigation so long that the only piece that was ever eventually built connects I-91 on the west end and I-84 on the east end.

By: Southern Buddhist

Southern Buddhist — Fri, 15 Aug 2008 16:48:18 +0000

PointSpecial left out one: Intrastate 66 in northern Virginia — it peels off of 81 just south of Winchester, Virginia and ends at the Potomac River just before crossing into DC.

By: Witty Nickname

Witty Nickname — Fri, 15 Aug 2008 16:00:11 +0000

Interstate 10 just east of Orange, Texas has the highest Interstate Highway mile marker in the country, mile marker 880. The mile markers reset at every state line, and Orange to El Paso is a good hike.

By: 8rustystaples

8rustystaples — Fri, 15 Aug 2008 15:52:22 +0000

Another interesting fact (unless things have changed), I-97 from Annapolis to Baltimore, MD is the shortest (2 digit) interstate highway at only 18 miles long.
I-90 from Seattle to Boston is the longest at nearly 3100 miles.

By: 8rustystaples

8rustystaples — Fri, 15 Aug 2008 15:45:20 +0000

Just to add to Lindsey’s info, spur and loop designations are derived from the interstate number they’re on with an additional first digit; even first digits signify loops, odd first digits signify spurs (e.g. I-610 is a loop on Interstate 10, I-310 is a spur).

By: Lindsey

Lindsey — Fri, 15 Aug 2008 14:50:01 +0000

And more fun interstate facts:

Interstates are numbered from south to north and west to east. East-west interstates end in even numbers, while north-south interstates end in odd numbers. Spurs and loops always have 3 digits.

Meanwhile, mile markers start from 0 in the west and increase as you move east on east-west interstates and from 0 in the south and increase as you move north on north-south interstates.

By: Lindsey

Lindsey — Fri, 15 Aug 2008 14:41:43 +0000

To follow up on PointSpecial,
I-12 in Louisiana begins in Baton Rouge and ends just past Slidell on the north shore of Lake Pontchartrain, when it once again meets I-10, which dips south to hit New Orleans, heads back north before going into Mississippi…

By: PointSpecial

PointSpecial — Fri, 15 Aug 2008 06:02:37 +0000

Wisconsin has an Interstate that is really an intrastate… I-43 has termini at Beloit and Green Bay.

Wow, actually, there are lots…

4, 12, 16, 17, 19, 27, 37, 43, 45, 49, 73, 86 (western portion), 87, 88 (both portions), 96, 97, 99

By: nutmeag

nutmeag — Fri, 15 Aug 2008 01:38:42 +0000

Thanks for the info. I lived in Hawai’i for 6 months and couldn’t figure that out. :-D