Interstate Highway Numbering Nonsense

[SD Mapman]

What do you mean "out west"? Plenty of rural spots in the east too, like the thirty-mile gap on the Mass Pike I mentioned earlier.

That's a very interesting definition of rural... ever been on I-80 in Wyoming?

At least with sequential numbering, you know once you reach the number just before the your exit, you know it's the next exit, whereas having exits 179, 214, 247, 267, 301..etc, you have no clue if your exit is coming up next unless you research ahead of time.

No, you just do simple math to figure out how far it is until the next exit. It's easier (at least for me) to go "Well I'm at Exit 2 and I need Exit 12 so it's a nice 10-mile cruise till I have to get off I-90" than "I'm at Exit 1 and I need Exit 4 so I'll just wait for two exits to pass, don't know where they are"

I'm pretty sure MMM mean stuff like this when he's talking about N-S labeling.

Saw that for the first time when I did my Northeast trip this summer and that makes a lot more sense than the A/B/C/D convention in the Midwest/Mountain West. Exit 396N tells me it's for I-29 North while Exit 396B tells me nothing.

[MultiMillionMiler]

Yes I am talking about the directions of the road you are exiting on to, not the "I-80N and I-80S". If you don't have to choose the direction until after fully exiting the highway, then just give the exit one number obviously, as you don't have to deal with direction until after the fact. But if it's an interchange between two interstates, where you have to choose a ramp at the exit, then simply label them two consecutive numbers so you know which number ahead of time instead of having to worry about the N or S labeling.

[Scott5114]

@Scott

Out of curiosity, been talking to Alps about Laws Depot? 

No, Jake Bear does a lot of ACSC sign replicas, so I've had to learn a lot about ACSC and CSAA signage from him to be able to help with that. Your photos were the first good actual photos that came up on Google Images.

[SEWIGuy]

A counter argument was not offered: if rural interstates shouldn't have mileage-based exits, what should the exit numbers be based off of?

The 1st exit: 1
The 2nd Exit: 2
The 3rd Exit: 3

And so on..

And no more N-S labeling, the same road in a different direction, should be a different Exit, especially if there are specific ramps you have to get on at the exit. At least with sequential numbering, you know once you reach the number just before the your exit, you know it's the next exit, whereas having exits 179, 214, 247, 267, 301..etc, you have no clue if your exit is coming up next unless you research ahead of time.

If you are at exit 179 and know you have to get off at exit 247, why do you care if there is one or ten exits in between?

It is much more important to me to know the mileage to my exit.

[SD Mapman]

I mean you could try to spot the mile markers on the side...

They're really easy to spot, especially in states like Missouri that have them every 0.2 miles on every single interstate; even in other states they're easy to find.

If you are at exit 179 and know you have to get off at exit 247, why do you care if there is one or ten exits in between?

It is much more important to me to know the mileage to my exit.

Exactly, that's how you get time estimates. Traveling in New Hampshire was annoying because of the sequential numbering (not that we ever had that far to go because the state is TINY).

[MultiMillionMiler]

Because such a huge difference in exits (not saying one that extreme exists anywhere in the country) may make me think I missed exits in between when there weren't any. But I know the longest stretch between exits is only 37 miles through the Salt Flats, and the 47 or 57 mile stretch between exits on the southern half of "Florida's Turnpike" isn't part of the interstate highway system so it doesn't count, but technically yes, if you know your ending exit you shouldn't be surprised.

[MultiMillionMiler]

I mean you could try to spot the mile markers on the side...

They're really easy to spot, especially in states like Missouri that have them every 0.2 miles on every single interstate; even in other states they're easy to find.

Depends how fast you are whizzing by them, but the way some states put the decimal value underneath the first 2 numbers can make it hard to read in that half a second, but point taken.

[kphoger]

But if you know your exit ahead of time, thar means you probably asked for a route on your phone, which means you should also know the mileage, and whether you could make it on gas or not.

Or...  here's a wild thought... the person I'm visiting gave me directions and said to get off at Exit #112.

[SD Mapman]

But if you know your exit ahead of time, thar means you probably asked for a route on your phone, which means you should also know the mileage, and whether you could make it on gas or not.

Or...  here's a wild thought... the person I'm visiting gave me directions and said to get off at Exit #112.

Or you looked at a map that had the exit numbers on it, as an alternative for those of us who are too anti-social to ask for directions lol

[SD Mapman]

Because such a huge difference in exits (not saying one that extreme exists anywhere in the country) may make me think I missed exits in between when there weren't any.

I mean if you're going from Exit 61 to Exit 332 who cares that you missed Exit 127, Exit 170, Exit 248, etc., unless you travel by counting the exits you pass...

[MultiMillionMiler]

Well I do joyride alot LOL but what's wrong with also posting signs every few miles telling you the number of miles to the next few exits. Don't even have to do math then at all, or add/subtract any mileage.

(BTW I just had to do this ridiculous captcha to log into one of my online social clubs, where I had to pick which set of 4 dice out of 4 choices which added up to 14, 7 times, made a mistake and had to do it another 7 times) so forgive me if I am a little bias against doing math right now..)

[MultiMillionMiler]

BTW, I am adding I-295 in NJ to the OP of this discussion. The path it takes is just ludicrous

[US 89]

I mean, it's not that hard to know the exit number you're getting off at and watch the mile markers you pass get closer and closer to that number...

[SEWIGuy]

Because such a huge difference in exits (not saying one that extreme exists anywhere in the country) may make me think I missed exits in between when there weren't any. But I know the longest stretch between exits is only 37 miles through the Salt Flats, and the 47 or 57 mile stretch between exits on the southern half of "Florida's Turnpike" isn't part of the interstate highway system so it doesn't count, but technically yes, if you know your ending exit you shouldn't be surprised.

It's much less surprising to know the mile I need to get off than a sequential exit number that may be a mile, ten miles, or twenty five miles down the highway.

[kphoger]

But if you know your exit ahead of time, thar means you probably asked for a route on your phone, which means you should also know the mileage ...

But if you know your exit ahead of time, thar means you probably asked for a route on your phone, which means it will tell you when your exit is coming up, so you don't even need to know if it's the next one or not to begin with.

[Scott5114]

And the giant exit signs also have the exit numbers in fifteen-inch-tall numbers at the top of them.

Seriously, this is something that a) has worked very well since the 1980s b) takes maybe fifteen minutes of travel on an Interstate highway to fully understand and begin using c) is far more useful for navigation than numbering conventions. Mile-based exit numbering is in the MUTCD, which (being issued by the FHWA, which is part of the actual government) means it probably has a stronger regulatory basis than the numbering conventions, which are just the policy of AASHTO, which is not actually part of the government.

[SD Mapman]

I mean if you're looking at the exit signs they're essentially proxy mile markers.

In the scenario below, if you come into SD from the west and want to go to Deadwood, you take Exit 17, and from the Wyoming border you can assume at roughly 75-80 mph you'll be to the exit in about 15 minutes. If it was Exit 6, all you'd know was that it was the 6th exit, not anything else. If you have to post mileage signs to the exits as was mentioned before, might as well number them by the mile anyway and save some money in the process.

[Scott5114]

...why is that in Clearview

[SD Mapman]

...why is that in Clearview

why not

[kirbykart]

What do you mean "out west"? Plenty of rural spots in the east too, like the thirty-mile gap on the Mass Pike I mentioned earlier.

That's a very interesting definition of rural... ever been on I-80 in Wyoming?

I'm pretty sure MMM mean stuff like this when he's talking about N-S labeling.

Saw that for the first time when I did my Northeast trip this summer and that makes a lot more sense than the A/B/C/D convention in the Midwest/Mountain West. Exit 396N tells me it's for I-29 North while Exit 396B tells me nothing.

I wasn't really trying to say that the East Berkshires are that rural in a cultural sense (although they are), more highlighting the extremely long exit gap. At least if there are a lot of exits to frontage roads in the middle of nowhere, you have something interesting to look at (the exit signs and the interchange).

I think your definition of rural is closer to "barren wasteland". Rural is when you have a small town every 5-20 miles and beautiful countryside in between. Vermont is rural. The Berkshires are rural. The Great Salt Flats are not rural. (Yes, I know the Salt Flats are in West Utah).


In response to "Exit 9N-S", yeah, aren't those great?! I'm so disappointed when I don't see those in other parts of the country. So helpful!

[SEWIGuy]

I mean to each their own, but I find it easier to look out for the giant exit signs than the tiny mile marker signs on the side of the road.

Actually I don't even need to do that.  I know the exit number I use when I am going home (183).  If I pass exit 100, I know I have 83 miles to my exit.  I add 83 to whatever my odometer reads, and now I continuously know how many miles I have until I get to my exit.  I could even use a tripometer if I don't want to do the math.

If it sequential, I have no idea what the mileage is.  Only how many exits are in between, which is absolutely irrelevant to me.

[MultiMillionMiler]

Isn't all that harder than just looking out for signs?

[SEWIGuy]

Isn't all that harder than just looking out for signs?

But the signs don't tell me what I need to know.  I want to know how many miles until my exit, which roughly tells me how much longer I need to go timewise.

Telling me how many exits I have left in a sequential system is irrelevant because I don't know the interval between those exits.

[US 89]

Isn't all that harder than just looking out for signs?

But the signs don't tell me what I need to know.  I want to know how many miles until my exit, which roughly tells me how much longer I need to go timewise.

Telling me how many exits I have left in a sequential system is irrelevant because I don't know the interval between those exits.

Also, the signs can only go so far out. I assume you're not going to put the next 40 exits and the mileages to them on a sign. Probably four is the max you'd be able to sign. With mile-based exit numbering, there is literally no limit to how far you have to be without knowing that distance. Short of resetting numbers at a state line, but that's going to affect sequential numbers anyway.

Out in the sticks, pretty much all exits look alike. They blend together. It's really easy to lose track of how many you pass especially if there's a lot of them and not a lot of cities in between. If I'm on I-80 leaving Rock Springs, Wyoming and I know I need to get to exit 211 in Rawlins... yeah, there are 22 exits between them, but it is infinitely more useful to know that it's 104 miles away. Not only am I going to get constant reassurances of how far I have left with the passing mile markers, but those reassurances are consistent and I can estimate travel times with that information. Even without doing any exact calculations, I'll notice that the exit numbers are about 100 miles apart, so assuming I go a little faster than 60 mph (a mile a minute) it'll take me probably somewhere around 90 minutes. (By the way, Google says 86 minutes, which I only looked up after I made that guess.) I can't do that with sequential numbering, because the exits are anywhere from 2 to 9 miles apart from each other.

Put it this way. Joe Q. Farmer has no idea the interstates are on a grid system, or if he does, he thinks it's some nerdy thing that won’t ever be useful and would make him sound weird if he told anyone. But he will religiously use the same sort of quick mental math I just described using the exit numbers.

[SEWIGuy]

Put it this way. Joe Q. Farmer has no idea the interstates are on a grid system, or if he does, he thinks it's some nerdy thing that won't ever be useful and would make him sound weird if he told anyone. But he will religiously use the same sort of quick mental math I just described using the exit numbers.

Yeah, and you are 100% right about the general knowledge of the grid system. IMO the vast majority of people either have no idea, or at best a vague knowledge of the interstate grid. So the fact that I-82 is north of I-84 doesn't bother them in the least.