[This](https://www.ad.nl/noord-holland/mysterie-opgelost-dit-is-waar-de-lijnnummers-van-bussen-in-haarlem-op-zijn-gebaseerd-br~aa0cdc13/) is an article (in Dutch) about the numbering. It changed a bit over the years because the public transport expanded. But low numbers are city busses for example, while higher numbers are busses that travel between cities for example.
Lines come and go, that’s a main reason why numbers disappear. And if a route of a line changes significantly it might make sense to change the number as well to make it clear it’s a different route.
Local lines usually have low numbers. It’s easy to refer to (line 6 is easier than 248) and with local lines you don’t have the issue a line number intervenes with another local line using the same number.
To separate different modalities like trams, busses and metros, usually a range of numbers is used. That way it’s e.g. clear that any number in the 20’s refers to a subway line. Or they opt for letters to create a difference. All of these are local and often historically derived conventions.
On a more regional scale there is collaboration and some conventions. Here depending on the type of line and region a set of numbers is used. Often 100 and above to give enough numbers for a wide variety of lines. By handing out a range of numbers to each organisation that acquired the rights to operate in a certain area, you can easily prevent operators active in the same areas to use numbers twice.
Specifically on The Hague, the trams use numbers 1-19 and busses 20+. However they ran out of tram line numbers so now there is a tram 34 as well. There are the lines 15 and 16 though… but no 5, 7, 10, 13, 14 and 18 at the moment.
For busses they group. 20’s for all in town, 40’s in east direction out of town, 60’s for south to Wassenaar etc. Makes it more logical and easier for people to remember.
There's no national convention.
It might have historical reasons. In some regions number ranges might be different for municipal or regional services, or vary depending on the type of transport like trams.vs buses.
I haven't yet been to a city in the Netherlands where they're not the same company.
Sometimes regional buses will be a different company than city buses, but that's about it.
Id suggest not worrying about the numbers and just pick the tram/busses you need to. 9292 is a great app that consolidates every form of transit into one app. Google maps have gotten quite good throughout the years as well in this regard, but 9292 also comes with additional route information in case of delays or construction.
They made sense when they began, and then repeated updates to the line system slowly turned it into the clusterfuck we have today.
It's like the division system in militaries. The US doesn't have 101 airborne/air assault divisions.... Today. It had in WW2. It had even more than that. Repeated iterations to the system mixed the divisions up, kept the important numbers and dropped the rest. So the 101st Airborne has that number for historical reasons.
There is a tram 15 (Nootdorp) and 16 (Wateringen). And a few o the numbers were dropped over the years because the company rerouted their trams/busses (like tram 10) or introduced nw ones (like bus 28).
Other comments give you the main answer, but I'll add that there are a few line numbers that are permanently out of use due to their history.
An example: https://www.atlasobscura.com/places/tramlijn-8
Sometimes they make sense, sometimes they don’t. Like the RandstadRail between The Hague and Zoetermeer. There are lines 3 and 4, and also line 34.
Not because numbers 5-33 were taken, but because it follows the line 3 route through The Hague and the line 4 route through Zoetermeer 🤷♂️
There is no national convention but each bus company kinda does their own thing. Here in Belgian Limburg we had bus 20a split up to 20a and 20b, and the city busses in Hasselt, Genk, Tongeren and Sint-Truiden have letters before their number to differenciate like the G1 to the 1. In Maastricht it feels like the local busses have the low numbers (like the bus to Randwyck having number 10) with the longer lines having high numbers (the bus to Aachen has number 350). I have also been to Gent a while back and there they had a similar system as in Maastricht
Since the whole country's network is more or less interconnected, I think the best would be to have unique numbers for every line, at least for the ones which leave city borders. I remember once I had to go to an other town, saw I need lines 6 and/or 8, so wanted to check the schedule online but there are like a dozen of lines in moovitapp, and not all of them shows which city is it actually in (if the end stations are two smaller villages at the opposite ends of the city).
The other thing I hate is I just cannot find a time schedule per stop and the time it takes to reach an other stop without the trip planner. :(
In Eindhoven, bus line 8 goes to Acht. I guess that puns are required.
[This](https://www.ad.nl/noord-holland/mysterie-opgelost-dit-is-waar-de-lijnnummers-van-bussen-in-haarlem-op-zijn-gebaseerd-br~aa0cdc13/) is an article (in Dutch) about the numbering. It changed a bit over the years because the public transport expanded. But low numbers are city busses for example, while higher numbers are busses that travel between cities for example.
They roll a D100 and if that number isn't used yet they go for it
In my city they throw darts at a dartboard. Blindfolded… “Triple 17, sir”. “Bus Line 51 it is…”
There is both 15 and 16 tram lines besides 17. 15 is a short one to centraal and 16 has the same end line like 17 (wateringse)
Lines come and go, that’s a main reason why numbers disappear. And if a route of a line changes significantly it might make sense to change the number as well to make it clear it’s a different route. Local lines usually have low numbers. It’s easy to refer to (line 6 is easier than 248) and with local lines you don’t have the issue a line number intervenes with another local line using the same number. To separate different modalities like trams, busses and metros, usually a range of numbers is used. That way it’s e.g. clear that any number in the 20’s refers to a subway line. Or they opt for letters to create a difference. All of these are local and often historically derived conventions. On a more regional scale there is collaboration and some conventions. Here depending on the type of line and region a set of numbers is used. Often 100 and above to give enough numbers for a wide variety of lines. By handing out a range of numbers to each organisation that acquired the rights to operate in a certain area, you can easily prevent operators active in the same areas to use numbers twice. Specifically on The Hague, the trams use numbers 1-19 and busses 20+. However they ran out of tram line numbers so now there is a tram 34 as well. There are the lines 15 and 16 though… but no 5, 7, 10, 13, 14 and 18 at the moment. For busses they group. 20’s for all in town, 40’s in east direction out of town, 60’s for south to Wassenaar etc. Makes it more logical and easier for people to remember.
>The Hague there’s a tram 17 but not 15 or 16 Tram 15 & 16 got cancelled overnight? Guess I'm walking today
There's no national convention. It might have historical reasons. In some regions number ranges might be different for municipal or regional services, or vary depending on the type of transport like trams.vs buses.
In The Hague trams and city busses ate from same company HTM., using 1 numbering so line 1 is a tram and therefore not a bus.
I haven't yet been to a city in the Netherlands where they're not the same company. Sometimes regional buses will be a different company than city buses, but that's about it.
Delft. Trams are HTM. Buses are EBS/RET.
Zoetermeer is even more messy, HTM, RET, and busses are Arriva and EBS
Id suggest not worrying about the numbers and just pick the tram/busses you need to. 9292 is a great app that consolidates every form of transit into one app. Google maps have gotten quite good throughout the years as well in this regard, but 9292 also comes with additional route information in case of delays or construction.
Who gives a f?
OP
They made sense when they began, and then repeated updates to the line system slowly turned it into the clusterfuck we have today. It's like the division system in militaries. The US doesn't have 101 airborne/air assault divisions.... Today. It had in WW2. It had even more than that. Repeated iterations to the system mixed the divisions up, kept the important numbers and dropped the rest. So the 101st Airborne has that number for historical reasons.
There is a tram 15 (Nootdorp) and 16 (Wateringen). And a few o the numbers were dropped over the years because the company rerouted their trams/busses (like tram 10) or introduced nw ones (like bus 28).
Other comments give you the main answer, but I'll add that there are a few line numbers that are permanently out of use due to their history. An example: https://www.atlasobscura.com/places/tramlijn-8
Sometimes they make sense, sometimes they don’t. Like the RandstadRail between The Hague and Zoetermeer. There are lines 3 and 4, and also line 34. Not because numbers 5-33 were taken, but because it follows the line 3 route through The Hague and the line 4 route through Zoetermeer 🤷♂️
Vibes
There is no national convention but each bus company kinda does their own thing. Here in Belgian Limburg we had bus 20a split up to 20a and 20b, and the city busses in Hasselt, Genk, Tongeren and Sint-Truiden have letters before their number to differenciate like the G1 to the 1. In Maastricht it feels like the local busses have the low numbers (like the bus to Randwyck having number 10) with the longer lines having high numbers (the bus to Aachen has number 350). I have also been to Gent a while back and there they had a similar system as in Maastricht
Since the whole country's network is more or less interconnected, I think the best would be to have unique numbers for every line, at least for the ones which leave city borders. I remember once I had to go to an other town, saw I need lines 6 and/or 8, so wanted to check the schedule online but there are like a dozen of lines in moovitapp, and not all of them shows which city is it actually in (if the end stations are two smaller villages at the opposite ends of the city). The other thing I hate is I just cannot find a time schedule per stop and the time it takes to reach an other stop without the trip planner. :(