# Counting stops without ambiguity

A typical conversation on a bus:

Alice: Have we reached our stop yet, Bob?

Bob: No, Alice. Two more stops to go.

Alice: Do you mean "two more stops, then ours" or "one more stop, then ours"?

I find it hard to express concisely and unambiguously how many more stops there are until we have to get off the bus. Any suggestions?

A few thoughts. Obviously, "next stop" is pretty clear. I find "next but one" unambiguous too, but then "next but seven" is getting a bit awkward. What if the bus is sitting at a stop while you speak - should that stop count or not? I wonder if one could find a way of counting the number of journey sections remaining, rather than the number of stops remaining.

• No, Alice. Our stop is the nth after this one. OR We get off at the nth stop after this one, etc. May 18, 2013 at 13:08
• Certainly a possibility, but there is room for improvement because is you have to remember to subtract 1 from n. For instance, "the 7th stop" is the same as "the 6th stop after this one". May 18, 2013 at 13:25
• The form of Alice's question implies that they are at (or pulling up to) a stop. If they're between stops Bob may say "the nth stop after the last one" or "the (n-1)th stop after the next one". May 18, 2013 at 13:33
• Also see What highway exit does “Next Exit” refer to? and the questions linked to Which day does “next Tuesday” refer to? May 18, 2013 at 13:44
• This is known in the trade, by the way, as a "fencepost error"; it happens a lot with arrays starting from a[0] being interpreted as starting at a[1], or vice versa. The metaphor is an apt one, since there is always one more fencepost than the number of fence segments. May 18, 2013 at 16:54

The general principle is that you don't count the stop that you are at. From this, we can derive the following scenario.

You're at station A and want to get to station D. You don't know yet that there are only stations B and C in between. You ask the station attendant/person waiting/someone who knows:

How do I get to D from here?

The attendant replies:

Oh, just get on the train/bus/subway and go 3 stops.

the stops being B, C, and your goal D, and you don't count the stop you're at. Looking at the map, B is 1 stop, C is 2 stops, and D is 3 stops, you count from one starting with the next stop and you stop counting on the goal. "Go 3 stops." -> count to 3, the stop you're on at 3 is your goal.

To be explicit, let's follow this all the way to your destination D.

So you've just got on the bus at A, and someone asks (the bus may have started up or maybe not left yet):

How far to D?

The correct and universally understood response that you make (because now you know) is:

3 stops.

Now you're on the bus and it has stopped at B. Same question How far is D?:

2 more stops til D

(works also if the bus is between B and C)

The bus is at C now. How many more stops?

1 more stop

If you're between C and D, its either

1 more stop.

or

The next stop is where we get off.

You're coming up on D... what do you say to someone who doesn't know? All they know is that they're still between C and D. The answer is mostly the same.

This is our stop.

It's coming up now.

1 more stop.

The next stop.

So the principle is, don't count the stop you are currently at.

As an aside, 'normal' people count starting from 1. I make this explicit because some technically minded people start counting from 0, which is logically consistent only if you are considering the empty set. So you could say that you can count this stop if you also start counting at 0.

• +1- although, the other day while giving directions to tourists on the subway I was asked if I was including the station in which we were standing (incidentally, at the end of the line) in my station count...thank goodness for subway maps. May 18, 2013 at 14:09
• @batpigandme: I can't tell if this is a universal (all languages do my answer) or if there is variation (like what number floor above the ground floor, 1st (Europe) or 2nd (US), or what's your age at 18 months, 1 year (most languages) or 2 years (Chinese). As to your tourists, it could just be being thrown into a foreign land that forces overthinking and doubt. May 19, 2013 at 14:06
• good point. Having the airport stop en route to work has made me a bit impatient with touristy troubles, but I have certainly needed quite a bit of hand-holding myself when navigating foreign places. Also, I think this might be one of those mental math things where some people do it one way and some do it another and it's just impossible to fully reconcile the two. My sister will always say "two more stops before our stop" which is clear enough, but certainly doesn't appeal to my 'default' station counting. May 19, 2013 at 14:12
• @batpigandme: Also, with planes it is different, you have layovers, which don't count the goal. For example: "How many layovers do you have on you way to LA?" "Two, one in NZ, and another in Hawaii." May 19, 2013 at 14:22
• @Mitch While all layovers are stops, stops aren't all layovers. May 20, 2013 at 7:40

I find two more stops, then ours quite unambiguous:
two more stops clearly does not include the current stop (if you're at a stop), but
it does include the next stop (if you are between stops).
(If you are just approaching a stop, I might say two more after this one, ....)
By saying then ours, I think the then clearly excludes all previously mentioned stops.

Or you could say something like We get off at the third stop (from here).
If you were just approaching a stop, I might amplify that to say We get off at the third stop after this one.

I like John Lawler's comment about counting fenceposts versus counting fence segments. I think the bus scenario might become less ambiguous if Alice and Bob count the segments between stops rather than the stops themselves. This way, there's no need to worry about whether the current stop is included, or about whether the destination is included. The only problem is, when the bus is halfway between stops, does the current segment count or not. This could be fixed by counting not the number of segments remaining, but the number of "complete segments" remaining.

So how about something like this?

Alice: Have we reached our stop yet, Bob?

Bob: No, Alice. Two more complete segments to go.

Alice: Thank you, Bob, that's most helpful of you. And thank you for being so unambiguous.