# RE: Interstate Highways in Hawaii **URL:** \ **Category:** Cecil's Columns/Staff Reports\ **Created:** [April 10, 2019, 2:48pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335 "2019-04-10T14:48:19Z")\ **Posts on this page:** 17\ **Page:** 1
**Author:** ![Fear\_Itself](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/fear_itself/32/19637_2.png) [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)\ **Post date:** [April 10, 2019, 2:48pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/1 "2019-04-10T14:48:19Z")
In the 1988 column entitled, [“How can there be interstate highways… in Hawaii?”](https://www.straightdope.com/columns/read/700/how-can-there-be-interstate-highways-in-hawaii/), Cecil says there are no interstate highways in Alaska. According to the website of the Federal Highway Administration, there are four designated interstate highways in Alaska, comprising 1082 miles of roadway. [https://www.fhwa.dot.gov/planning/national\_highway\_system/interstate\_highway\_system/routefinder/table03.cfm](https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table03.cfm) ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [April 10, 2019, 2:56pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/2 "2019-04-10T14:56:35Z")
> [@](#): > > Most of the lengths of the Interstates in Alaska are not constructed to Interstate Highway standards, but are small, rural, two-lane undivided highways. > **[List of Interstate Highways in Alaska](https://en.wikipedia.org/wiki/Interstate_Highways_in_Alaska)** ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [April 10, 2019, 3:04pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/3 "2019-04-10T15:04:06Z")
Also, Alaska’s interstate highways are not signed as interstate highways and have state numbers that do not match the federal interstate highway system. Interestingly enough, Puerto Rico, another island, has four interstate highways. ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [April 10, 2019, 3:37pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/4 "2019-04-10T15:37:35Z")
Another Interstate Highway that isn’t actually “interstate” is the Tri-State Tollway, which isn’t “Tri-State” at all. Going north to south, it begins at Northbrook, Illinois and ends just past South Holland, Illinois, just short of the Indiana border. [\*\*Map of the Tri-State Tollway \*\*](https://en.wikipedia.org/wiki/Interstate_294#/map/0) ---
**Author:** ![PastTense](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/pasttense/32/14550_2.png) [@PastTense](https://boards.straightdope.com/u/PastTense)\ **Post date:** [April 10, 2019, 3:55pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/5 "2019-04-10T15:55:41Z")
Thus the reason for Alaska having “Interstate Highways” is funding: the federal government has a separate pool of money to fund these highways and pays a higher percent of costs (vs state governments) than for other highways. ---
**Author:** ![Kent\_Clark](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kent_clark/32/105_2.png) [@Kent\_Clark](https://boards.straightdope.com/u/Kent_Clark)\ **Post date:** [April 10, 2019, 4:52pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/6 "2019-04-10T16:52:32Z")
> [@Fear\_Itself](#): > > In the 1988 column entitled, [“How can there be interstate highways… in Hawaii?”](https://www.straightdope.com/columns/read/700/how-can-there-be-interstate-highways-in-hawaii/), Cecil says there are no interstate highways in Alaska. > > According to the website of the Federal Highway Administration, there are four designated interstate highways in Alaska, comprising 1082 miles of roadway. > > [Table 3: Interstate Routes - FHWA Route Log and Finder List - Interstate Highway System - National Highway System - Planning - FHWA](https://www.fhwa.dot.gov/planning/national_highway_system/interstate_highway_system/routefinder/table03.cfm) But were they there in 1988, when Cecil wrote his column? ---
**Author:** ![kenobi\_65](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/kenobi_65/32/13178_2.png) [@kenobi\_65](https://boards.straightdope.com/u/kenobi_65)\ **Post date:** [April 10, 2019, 4:54pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/7 "2019-04-10T16:54:47Z")
> [@Jasmine](#): > > Another Interstate Highway that isn’t actually “interstate” is the Tri-State Tollway, which isn’t “Tri-State” at all. Going north to south, it begins at Northbrook, Illinois and ends just past South Holland, Illinois, just short of the Indiana border. Though, the Tri-State (I-294) is a classic example of the concept of an “[Auxiliary Interstate Highway](https://en.wikipedia.org/wiki/Interstate_Highway_System#Auxiliary_(three-digit)_Interstates).” They usually have a three-digit number, and the last two digits are the number of their “parent” Interstate. In the case of the Tri-State, it’s a “loop route,” and bypasses the center of Chicago, connecting up with its parent, I-94, to the north and to the south of the city (whereas I-94 goes through the center of the city). Many (maybe even most) auxiliary Interstates only run in a single state. ---
**Author:** ![That\_Don\_Guy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/that_don_guy/32/538_2.png) [@That\_Don\_Guy](https://boards.straightdope.com/u/That_Don_Guy)\ **Post date:** [April 10, 2019, 6:11pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/8 "2019-04-10T18:11:52Z")
I don’t think all “interstate” highways outside of Alaska and Hawaii are necessarily interstate. Does I-4 run anywhere outside of Florida? ---
**Author:** ![Jasmine](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/jasmine/32/2964_2.png) [@Jasmine](https://boards.straightdope.com/u/Jasmine)\ **Post date:** [April 10, 2019, 6:30pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/9 "2019-04-10T18:30:23Z")
I’ve been doing some research, and it’s very probable that funding has more to do with it than whether or not the highway spans more than one state. If you can get an Interstate highway built in Hawaii, the Federal Government provides most of the money through the National System of Interstate Highways special funding, thus saving the state a very large sum of money. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [April 10, 2019, 9:05pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/10 "2019-04-10T21:05:46Z")
> [@That\_Don\_Guy](#): > > I don’t think all “interstate” highways outside of Alaska and Hawaii are necessarily interstate. Does I-4 run anywhere outside of Florida? In the one or two digit category there are quite a few that are one-state only. I-2 in Texas is the lower numbered one. Search [this](https://en.wikipedia.org/wiki/List_of_Interstate_Highways) page for “only”. (My count is 20. YMMV.) ---
**Author:** ![DPRK](https://avatars.discourse-cdn.com/v4/letter/d/4491bb/32.png) [@DPRK](https://boards.straightdope.com/u/DPRK)\ **Post date:** [April 16, 2019, 1:09am UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/11 "2019-04-16T01:09:26Z")
Those [Alaskan Interstate Highways](https://upload.wikimedia.org/wikipedia/commons/1/1b/Interstate_Alaska_map.png) do in fact appear to lead to the Canadian border and the rest of the United States, thus making them legitimate interstate highways, as opposed to some of the obviously fake “interstate” highways noted above. ---
**Author:** ![glowacks](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/glowacks/32/5548_2.png) [@glowacks](https://boards.straightdope.com/u/glowacks)\ **Post date:** [June 24, 2019, 3:07am UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/12 "2019-06-24T03:07:31Z")
I-96 also starts and ends in Michigan, going from Detroit to Lansing to Grand Rapids to Muskegon, which is at the shore of Lake Michigan. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [June 24, 2019, 1:01pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/13 "2019-06-24T13:01:51Z")
> [@glowacks](#): > > I-96 also starts and ends in Michigan, going from Detroit to Lansing to Grand Rapids to Muskegon, which is at the shore of Lake Michigan. It’s on the “only” list I linked to above. It’s the 2nd highest single state one listed. (Reminder: 1 or 2 digits.) I-97 in MD is the highest. It would be interesting if there was a 1/2 digit interstate that started and stopped in the same state but passed thru another state. But that doesn’t appear to be the case. Guess which state has the longest “only” interstate? New York! Texas is in 2nd place by a good margin. ---
**Author:** ![campp](https://avatars.discourse-cdn.com/v4/letter/c/c5a1d2/32.png) [@campp](https://boards.straightdope.com/u/campp)\ **Post date:** [June 24, 2019, 1:18pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/14 "2019-06-24T13:18:33Z")
I believe the Interstate system was also conceived to be part of a civil defense plan, plus suitable for military use. ---
**Author:** ![DesertDog](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/desertdog/32/11503_2.png) [@DesertDog](https://boards.straightdope.com/u/DesertDog)\ **Post date:** [June 24, 2019, 2:55pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/15 "2019-06-24T14:55:02Z")
Yes. Among other [things](https://en.wikipedia.org/wiki/Interstate_Highway_standards), the maximum grade is 6%\* and the minimum clearance of underpasses is 16 feet, the height of a main battle tank atop a transporter. \*With a few exceptions ---
**Author:** ![blarson61](https://avatars.discourse-cdn.com/v4/letter/b/54ee81/32.png) [@blarson61](https://boards.straightdope.com/u/blarson61)\ **Post date:** [June 28, 2019, 11:04pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/16 "2019-06-28T23:04:57Z")
I can think of two of these in Texas. One, I69, has bits and pieces in other states, but none of them cross state borders to my knowledge. The other is I45, which runs from Galveston to Dallas, then just starts being a state highway up into Oklahoma. ---
**Author:** ![ftg](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/ftg/32/2801_2.png) [@ftg](https://boards.straightdope.com/u/ftg)\ **Post date:** [June 29, 2019, 12:47pm UTC](https://boards.straightdope.com/t/re-interstate-highways-in-hawaii/832335/17 "2019-06-29T12:47:04Z")
> [@blarson61](#): > > I can think of two of these in Texas. One, I69, has bits and pieces in other states, but none of them cross state borders to my knowledge. The other is I45, which runs from Galveston to Dallas, then just starts being a state highway up into Oklahoma. The list I linked to earlier lists 5 Texas only 1/2 digit interstates. As to I-69, the original segment from Indianapolis to Port Huron crosses a state line as well as two other state line crossings.