[Tagging] Maxweight wiki page changes

Minh Nguyen minh at nguyen.cincinnati.oh.us
Sat Jul 6 19:54:26 UTC 2019

On 2019-07-06 04:49, Colin Smale wrote:
> It is an intrinsic danger of international projects that words mean 
> different things to different people. Hence the importance of keeping 
> things objective, and recording facts, rather than judgements. It's 
> about what things ARE, not what they are CALLED. It really doesn't 
> matter if the tag uses "unladen" or "empty" or "tare" or indeed 
> "abc001". What is important is that the chosen tag is well-defined, so 
> people can translate the data to what it does (or does not) imply.
> For example (my definition):
> Bogie = composite of 2..n axles sharing a common load-bearing mechanism. 
> Not to be confused with a Close-Coupled Axle Group where each axle has 
> its own independent load-bearing mechanism.
> With unladen/tare/empty, this is probably not exactly the same as kerb 
> weight (Mass In Running Order), which includes things like fuel in the 
> tank. Or is it "dry weight" without even the weight of the brake fluid? 
> Is it defined as weight, or is it actually legally speaking mass? Which 
> value is most easily accessible for mappers? Which value is most useful 
> to data consumers?

This is an important point. Your average non-British layperson mapping 
businesses who happens to come across a weight restriction sign won't 
initially know the distinction between an axle and a bogie (guilty as 
charged), let alone tare and dry weight, so there's quite a risk of 
mistagging. Editor fields with human-readable labels can mitigate this 
risk somewhat, but after a modicum of research, I'm still unsure as to 
whether the signposted "empty weight" differs from "curb weight".

Personally, as an American, I don't have a problem with calling it 
either "empty" or "unladen" weight. I initially confused bogies with 
axles on the wiki, owing to "tandem" being much more common here, but I 
still find "unladen" to be self-explanatory, if slightly exotic. Maybe 
I've spent too much time pondering the maximum airspeed velocity of 
certain birds.

Are there any jurisdictions that make a distinction between specific 
definitions of "tare", "empty", "curb", or "dry" weight in weight 
restrictions? If not, there's no need to overdefine the tag. We already 
handwave about the definition of maxweight: does it refer to the weight 
of the portion of the vehicle currently on the bridge, or the entire 
vehicle? Different jurisdictions probably have differing definitions 
while using similar signs. Even the difference between empty and gross 
weight is insignificant for most trucks. [1]

To account for empty weight restrictions, a navigation application would 
have to ask the trucker their empty weight or perhaps the truck's 
make/model/configuration. It seems to me that the more important 
consideration is whether the application presents the user with the 
correct terminology. Whether the underlying data is based on uniform 
definitions internationally would be more important for analysis use 
cases, I suppose, but anyone trying to shoehorn the U.S. system of 
weight restrictions into a coherent international system is in for a 
world of hurt. [1]

[2] https://wiki.openstreetmap.org/wiki/Key:maxweight#United_States_2

minh at nguyen.cincinnati.oh.us

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