Weird fractions on distance signs

[mrsman]

... miles is that they divide nicely into haves, thirds, quarters, fifths, sixths, eighths, tenths, and even elevenths and twelfths in whole feet...

The next time I see a sign saying X/11 or X/12 miles will be the first.

Seriously guys, can't we just agree to use meters (preferably in hundreds or rarely fifties maybe on city streets) for stuff shorter than a mile? or for intermediate distances between 1 and 2 miles? Is it that much of a stretch? I would like to go all metric, but meters for walkable distances should be the thing.

When I was in ON last month, I had to keep thinking about distances when I saw "Right, 300 m" or similar signs.  I have a feeling for  1 or 2 km.  But not for some several hundred meters.

100 m is basically the length of a football field (goal line-to-goal line in the CFL or including one end zone in the US) or one 16-to-a-mile block. I think of "300 m" as "3 blocks" or "3 fields".

Meters and yards are very close in size.  That being said, the mindset for American drivers is more along the lines of miles (not even feet or yards work well).

8/10 mile is so close to 3/4 mile that I'm surprised it wasn't used.  Usually, you expect a sign to round to the nearest 1/4 miles unless it is a distance that is less than 1/4 mile.

[jmacswimmer]

I don't think anyone's mentioned this one yet: 4/5 mile on I-81 SB approaching I-64.

[Ned Weasel]

I don't think anyone's mentioned this one yet: 4/5 mile on I-81 SB approaching I-64.

That sign assembly is goofy for lots of reasons!  Who even thinks in fifths of miles?  Might as well round and say "3/4 MILE."  And "EAST/WEST?"  Both directions are implied when you leave off the cardinal directions entirely.  And then the MUTCD would slap them for misusing down arrows like that. 

[sprjus4]

I don't think anyone's mentioned this one yet: 4/5 mile on I-81 SB approaching I-64.

That sign assembly is goofy for lots of reasons!  Who even thinks in fifths of miles?  Might as well round and say "3/4 MILE."  And "EAST/WEST?"  Both directions are implied when you leave off the cardinal directions entirely.  And then the MUTCD would slap them for misusing down arrows like that. 

A lot of signs on the I-81 corridor are off like that.

[amroad17]

I don't think anyone's mentioned this one yet: 4/5 mile on I-81 SB approaching I-64.

That sign assembly is goofy for lots of reasons!  Who even thinks in fifths of miles?  Might as well round and say "3/4 MILE."  And "EAST/WEST?"  Both directions are implied when you leave off the cardinal directions entirely.  And then the MUTCD would slap them for misusing down arrows like that. 

A lot of signs on the I-81 corridor are off like that.

Relics from the 1960's that are, unfortunately, carbon copied--although I believe these signs may be second set of signs that have been erected here (changed sometime in the late 1980's).  The original US 250 sign would have had a black border around the shield along with a smaller font (Series C, I believe).

It is a shame that some DOT's do not update some of their signage.  Not everything remains the same forever.

[sprjus4]

^

Don't know how I didn't think of this before, but another Virginia example of 1/3 mile on VA-168 in Chesapeake, VA at Exit 13 / VA-168 Business. The other direction uses 1/4 mile.

1/3 mile on US-13 in Virginia Beach, VA at VA-225. The other direction also uses 1/3 mile. Down the road, the exit for US-60 also uses 1/3 mile. The exits on US-13 Northampton Blvd in Virginia Beach have some clearly not standard signage, not just because of the 1/3 but font and layout overall. The other direction coming off the CBBT has some more standard signage.

1/5 mile on US-460 in Suffolk, VA approaching the US-58 interchange. Some interesting US route shields. The same situation exists at the VA-32 approach to the US-58 freeway to the east.

[Occidental Tourist]

800 feet on CA 133 south at the 405.



There used to be a 10ths of a mile measurement on an overhead advance interchange sign at the Downtown exit for the 710 in Long Beach, but it was replaced.

[mrsman]

IMO, all mileage signs in the US should be in miles, not feet or yards, even if something is very close.  The use of a small fraction will indicate its proximity.

Any sign less than 1/10 of a mile is so close as to just mark it there with an arrow or something.

Acceptable mileage signs for short distances are: 1/10, 1/8, 1/4, 1/3, 3/8, 1/2, 5/8, 3/4.  Any distances above 3/4 should only be for /4 and /2 fractions: (1, 1 1/4, 1 1/2, 1 3/4, etc.)

Any distance that doesn't fit the above should be rounded to the closest fraction that is on the list.  So 800 feet is closest to 1/8 mile and that is what should be reflected on the above sign.

[Ned Weasel]

IMO, all mileage signs in the US should be in miles, not feet or yards, even if something is very close.  The use of a small fraction will indicate its proximity.

Kilometers, preferably!  But I think the MUTCD agrees with you on using miles and fractions thereof, instead of feet or anything else

Any sign less than 1/10 of a mile is so close as to just mark it there with an arrow or something.

Disagree.  See the MUTCD's strict rules on down arrows.  I'd rather use "NEXT EXIT," "NEXT RIGHT," or (if applicable) "NEXT LEFT."

Acceptable mileage signs for short distances are: 1/10, 1/8, 1/4, 1/3, 3/8, 1/2, 5/8, 3/4.  Any distances above 3/4 should only be for /4 and /2 fractions: (1, 1 1/4, 1 1/2, 1 3/4, etc.)

I think 1/3 is less intuitive.  Our system kind of likes dividing things into multiples of two.  I'd round to 1/4 or 3/8.  And I don't even think 5/8 is necessary; that could be rounded to 1/2 or 3/4.

Any distance that doesn't fit the above should be rounded to the closest fraction that is on the list.  So 800 feet is closest to 1/8 mile and that is what should be reflected on the above sign.

This came up in the "Redesign This!" thread, and I ended up changing some of my own redesigns in exactly the way you describe.

[roadfro]

IMO, all mileage signs in the US should be in miles, not feet or yards, even if something is very close.  The use of a small fraction will indicate its proximity.

Any sign less than 1/10 of a mile is so close as to just mark it there with an arrow or something.

Acceptable mileage signs for short distances are: 1/10, 1/8, 1/4, 1/3, 3/8, 1/2, 5/8, 3/4.  Any distances above 3/4 should only be for /4 and /2 fractions: (1, 1 1/4, 1 1/2, 1 3/4, etc.)

Any distance that doesn't fit the above should be rounded to the closest fraction that is on the list.  So 800 feet is closest to 1/8 mile and that is what should be reflected on the above sign.

I agree that, especially when talking about guide signs on freeways and major highways, distances should be given in miles.

However, I disagree about the short fractional distances. Some drivers already have little concept of fractional distances like 1/4 mile especially while at freeway speed, so there's no need to introduce additional ambiguity when the distance is short. I'm usually good with time and distance, and even I have little concept of what 1/8 or 1/3 of a mile is.

What I would propose is using 1/4, 1/2, & 3/4, like we do now. But in unusual circumstances of closely-spaced exits, lane drops, and other unexpected situations that happen within less than 3/4 mile, tenths of a mile fractions (1/10, 2/10, etc.) would become an option. Many vehicle odometers (or at least a trip odometer) already display (or can be displayed) in decimal tenths, so that is a fractional distance that people either already have some concept of or can easily gauge on their odometer. Anything less than 1/10 of a mile (528 feet) could display in hundreds of feet, to convey the urgency/immediacy of the situation.

[kphoger]

Some drivers already have little concept of fractional distances like 1/4 mile especially while at freeway speed, so there's no need to introduce additional ambiguity when the distance is short. I'm usually good with time and distance, and even I have little concept of what 1/8 or 1/3 of a mile is.

I know that 1/3 is somewhere between 1/4 and 1/2, and that's all I really need to know.

I know that 1/8 is half as much as 1/4, and that's all I really need to know.

Fractions like 3/8 and 5/8, on the other hand...  Please don't make people do math while driving.  In my opinion, 3/4 is the only fraction that should have anything other than a 1 on top.

I also think /2, /3, /4, and /8 should be the only acceptable flavors of fraction.  Minnesota, it's not worth my time to figure out how much closer 1/5 is to 1/4 than it is to 1/8.

[mrsman]

Some drivers already have little concept of fractional distances like 1/4 mile especially while at freeway speed, so there's no need to introduce additional ambiguity when the distance is short. I'm usually good with time and distance, and even I have little concept of what 1/8 or 1/3 of a mile is.

I know that 1/3 is somewhere between 1/4 and 1/2, and that's all I really need to know.

I know that 1/8 is half as much as 1/4, and that's all I really need to know.

Fractions like 3/8 and 5/8, on the other hand...  Please don't make people do math while driving.  In my opinion, 3/4 is the only fraction that should have anything other than a 1 on top.

I also think /2, /3, /4, and /8 should be the only acceptable flavors of fraction.  Minnesota, it's not worth my time to figure out how much closer 1/5 is to 1/4 than it is to 1/8.

Not a bad concept.  For any distances that are really short and cannot be rounded up to 1/8 because of immediacy, just say next right or next exit. (as stridentweasel suggested).

Then 1/8, 1/4, 1/2, 3/4, 1.  For distances that are between these points, one should round to the nearest identified point.  So if something is between 1/4 or 1/2 mile away use either 1/4 or 1/2, whichever is closer to the actual distance as both indications give a reasonable indication of the relative immediacy of the exit.

The only difficulty is if you have to distinguish many closely spaced exits.  Like along I-90/94 in Chicago's west loop (especially before they removed some of those exits).  There, you had 6 exits that were 500 feet apart from each other.  500 ft is close to 1/10 mile, but if you had to only use 1/8 the estimate won't make sense.  The fifth exit would be 1/2 mile, but you would end up listing it as 5/8 to distinguish the previous exit. Fortunately, this situation is rare.

[kphoger]

So if something is between 1/4 or 1/2 mile away use either 1/4 or 1/2, whichever is closer to the actual distance as both indications give a reasonable indication of the relative immediacy of the exit.

I prefer rounding down in almost all cases.  Much better that drivers be surprised at how far away an exit is than how close it is.

The only difficulty is if you have to distinguish many closely spaced exits.  Like along I-90/94 in Chicago's west loop (especially before they removed some of those exits).  There, you had 6 exits that were 500 feet apart from each other.  500 ft is close to 1/10 mile, but if you had to only use 1/8 the estimate won't make sense.  The fifth exit would be 1/2 mile, but you would end up listing it as 5/8 to distinguish the previous exit. Fortunately, this situation is rare.

How many are listed on one sign gantry, though?  Typically, all five exits wouldn't be listed together.

[jeffandnicole]

Outside of 1/4, 1/2, and 1, I wouldn't list any others unless absolutley necessary.  As mentioned above, just round to the next shortest distance. 

1/3 and 1/4 are very close.  Just go with 1/4.  Maybe you could make an argument for 1/10 or 1/8, but that's about it.  Any other fraction isn't going to compute with a population that generally doesn't understand fractions anyway.  At the Supermarket, Deli workers use fractions all the time (I'll take a 1/2 pound of cheese, etc). I asked - once - for 1/3 of a pound of ham.  The person didn't have a clue, because she then had to convert that to a decimal.  0.33 is fine.  0.3 is acceptable.  0.35, whatever.  It would've been easier changing my order to 1/4 or 1/2 than to involve the entire deli counter in figuring out what 1/3 equaled.

[Ned Weasel]

Any other fraction isn't going to compute with a population that generally doesn't understand fractions anyway.

https://youtu.be/nFTRwD85AQ4

Honestly, my preference would be to use kilometers and decimal points, though.  Now what are the chances of that?   

[ilpt4u]

Any other fraction isn't going to compute with a population that generally doesn't understand fractions anyway.

https://youtu.be/nFTRwD85AQ4

Honestly, my preference would be to use kilometers and decimal points, though.  Now what are the chances of that?   

If Fractions are too much to compute, Unit Conversions are really a bridge too far

Just start with 5/8 mile and 1 1/4 mile being common advance signage, to get the US traveling pubic ready to simply change those to 1 km and 2 km, respectively. 1/2 mile and 1 mile don't convert cleanly to kilometers

[Ned Weasel]

If Fractions are too much to compute, Unit Conversions are really a bridge too far

That's why the metric system is easier!  There are no unit conversions that aren't multiples or divisions of 10.

They never should have taken kilometers per hour off of speedometers in U.S.-market cars.  I suppose the car companies may have resigned themselves to the improbability of the U.S. joining the vast majority of the world within the lifespan of the car.  But did they really think most customers would never want to drive into Canada or Mexico?

At least some newer cars have electronic speedometers that where you can just press a few buttons and switch it.  But with my 2009-model car, all I got was miles per hour, and if I ever take a trip across one of the borders, I'm just gonna have to get a sticker to put over it and make certain it's sized and placed correctly.

Just start with 5/8 mile and 1 1/4 mile being common advance signage, to get the US traveling pubic ready to simply change those to 1 km and 2 km, respectively. 1/2 mile and 1 mile don't convert cleanly to kilometers

I'd love to think that's the reason KDOT replaced a one-mile advance guide sign with this: https://goo.gl/maps/u2toCzTc9C4PPhv27 .  But what are the chances!?

[ilpt4u]

If Fractions are too much to compute, Unit Conversions are really a bridge too far

That's why the metric system is easier!  There are no unit conversions that aren't multiples or divisions of 10.

I meant that Unit Conversions necessary to get the traveling public used to thinking in meters/kilometers and Metric, compared to feet/miles and Imperial

Yes, once Metric is the normal, everything is based on the powers of 10 to convert metric units. But getting from their Imperial counterparts are a bit less straight forward

The only reason I commonly know that (roughly) 1600 meters = 1 mile is because back in High School 4 laps on the 400 meter track was regarded as 1 mile. It is not the exact conversion, but its close (1609.34 meters). 1 yard=3 feet=(roughly) 1 meter. 12 inches=1 foot=(roughly) 30 centimeters, commonly known from a ruler

My favorite conversion is 355 ml=12 fl oz, on every soda and beer can made. For quicker liquid/volume ballpark conversions, 1 quart=(roughly) 1 liter

[Ned Weasel]

I meant that Unit Conversions necessary to get the traveling public used to thinking in meters/kilometers and Metric, compared to feet/miles and Imperial

Yes, once Metric is the normal, everything is based on the powers of 10 to convert metric units. But getting from their Imperial counterparts are a bit less straight forward

I get your point, but--  When I was fortunate enough to have the privilege of driving a big-rig long-haul, when I drove in Canada, I just stopped thinking in miles and started thinking in kilometers.  Speed limit 80 km/h?  No problem; it's right there on my speedometer.  How about estimating time?  Well, many of us probably think in terms of 60 miles per hour for long-distance trips, and that's obviously a mile a minute.  So, when we see a sign saying something close to 120 miles, we think of it as two hours, and when we see 30 miles, we think of it as a half hour.  The situation is still easy if you think in terms of 100 kilometers per hour, which is the speed limit in much of Ontario.  See a sign that gives a distance close to 200 kilometers?  Okay, that's about two hours.  See a something listed as being about 50 kilometers away?  No sweat; that's about a half-hour.  It's pretty easy to remember that every 25-kilometer increment roughly corresponds to 15 minutes (a quarter-hour) of travel time.

That's literally how I thought when I drove in Canada.  Miles just got stored away in a filing cabinet after I crossed from Detroit into Windsor.

Now, you may be inclined to mention the elephant in the room: the Jeffersonian Grid.  Not much of an issue in the Northeast; but come down to the Midwest or West, and it's everywhere, perhaps most prominently in Phoenix.  It brings up questions for which I do not have a sure-fire answer.  Will people care about street numbers in increments of eight or 16 being a mile apart?  Or will they just accept that the spacing of street numbers doesn't neatly align with kilometers, much like the spacing of streets themselves in New England doesn't typically align with miles?  Will people get upset that the names "Six Mile Road," "Seven Mile Road," "Eight Mile Road," etc., are no longer relevant to measured distances?  Or will they just accept them as named relics of an old system, much like the plethora of "turnpikes" in the Northeast that haven't been toll roads in any of our lifetimes?

[amroad17]

^ The metric system will kill Detroit and the north metro area.    Yes, named relics of an old system.

I am rather ambivalent on whether we go to metric or not.  I know I can adjust to the change, however, how many others (especially "Karen's") may not adjust to the change.   

[ilpt4u]

The Metric System wouldn't be too awful for the Chicago Street Grid, since it is 8 blocks = 1 Mile aka 1 block = 1/8 mile

That also just happens to be 5 blocks = 1 kilometer

[webny99]

I also think /2, /3, /4, and /8 should be the only acceptable flavors of fraction.  Minnesota, it's not worth my time to figure out how much closer 1/5 is to 1/4 than it is to 1/8.

Very much agree. And "Minnesota" fit perfectly in that [insert cuss word of choice] situation: This one always throws me.

We could potentially add /10 to the list, but by the time you get to 1/10, you might as well measure in feet... as NYSDOT figured out here. I'd argue you could probably get rid of 1/8 on that basis as well.

[kphoger]

But with my 2009-model car, all I got was miles per hour, and if I ever take a trip across one of the borders, I'm just gonna have to get a sticker to put over it and make certain it's sized and placed correctly.

Huh?  You mean a sticker to cover up all the m.p.h. with km/h numbers?  That sounds unnecessary to me.

I drive in Mexico all the time, and I generally figure out what speed to drive by m.p.h., even though the speed limits are in km/h.  Here's how I figure it:


speed limit 110 km/h → somewhere around 68 mph → figure on driving 5 mph over the limit → cruise at 70 to 75 mph

speed limit 100 km/h → somewhere around 60 mph → figure on driving 5 to 10 mph over the limit → cruise at 65 to 70 mph

speed limit 80 km/h → almost exactly 50 mph → figure on driving 10 mph over the limit → cruise at 60 mph

anything under 80 km/h → follow the prevailing speed of traffic


So I only really memorize three conversions for normal highway driving.  All of my decisions from that point on are made based on m.p.h.

[Ned Weasel]

Huh?  You mean a sticker to cover up all the m.p.h. with km/h numbers?  That sounds unnecessary to me.

Ideally, I'd have a transparent sticker that I can overlay on the speedometer that allows me to see both at the same time.  I'm not sure if anyone makes those, but I might be able to find a way to get one printed.

I drive in Mexico all the time, and I generally figure out what speed to drive by m.p.h., even though the speed limits are in km/h.  Here's how I figure it:


speed limit 110 km/h → somewhere around 68 mph → figure on driving 5 mph over the limit → cruise at 70 to 75 mph

speed limit 100 km/h → somewhere around 60 mph → figure on driving 5 to 10 mph over the limit → cruise at 65 to 70 mph

speed limit 80 km/h → almost exactly 50 mph → figure on driving 10 mph over the limit → cruise at 60 mph

anything under 80 km/h → follow the prevailing speed of traffic


So I only really memorize three conversions for normal highway driving.  All of my decisions from that point on are made based on m.p.h.

Your method sounds workable, just not ideal.  I'd still be trying to find a way to get the km/h units somewhere my speedometer needle can point to them accurately, at least in increments of 20, just because I'm like that.

[michravera]

But with my 2009-model car, all I got was miles per hour, and if I ever take a trip across one of the borders, I'm just gonna have to get a sticker to put over it and make certain it's sized and placed correctly.

Huh?  You mean a sticker to cover up all the m.p.h. with km/h numbers?  That sounds unnecessary to me.

I drive in Mexico all the time, and I generally figure out what speed to drive by m.p.h., even though the speed limits are in km/h.  Here's how I figure it:


speed limit 110 km/h → somewhere around 68 mph → figure on driving 5 mph over the limit → cruise at 70 to 75 mph

speed limit 100 km/h → somewhere around 60 mph → figure on driving 5 to 10 mph over the limit → cruise at 65 to 70 mph

speed limit 80 km/h → almost exactly 50 mph → figure on driving 10 mph over the limit → cruise at 60 mph

anything under 80 km/h → follow the prevailing speed of traffic


So I only really memorize three conversions for normal highway driving.  All of my decisions from that point on are made based on m.p.h.

I always think that 120 km/h is very close to 75MPH; 130 km/h is very close to 80MPH; 90 km/h is very close to 55MPH and 50 km/h is very close to 30MPH. In between, it's only an approximation anyway, so stay close to 90 km/h when you need to be slow on the highway and 120 km/h when your way is clear. 50 km/h is more normal on city streets. Maybe a bit faster on thoroughfares.