A prefabricated bridge typically has a plaque that indicates the maximum load that it can carry. This may be called a “vehicle load”, but it shouldn’t be confused with a traffic restriction. For example, this footbridge has a “vehicle load limit” of 5 short tons. No motor vehicles are allowed on the footpath, and I don’t think any emergency vehicle would physically fit on the bridge, so this isn’t really about prohibiting vehicles that heavy from traversing the bridge. The manufacturer rates all their bridges just like any other load-bearing product.
maxweight=5 st feels contrived on the highway=footway, but what about the man_made=bridge area? In this context, would maxweight=* refer to a load limit instead of a vehicle weight limit, or should the load limit be a distinct key? id-tagging-schema’s Bridge Area preset used to include a maxweight=* field, but it was recently removed as redundant to maxweight=* on the highway=* way.
Incidentally, iD’s Elevator preset still has a maxweight=* field. maxweight=* is documented as the “maximum weight” of a highway=elevator, specifically a passenger weight. But most elevators list the total carrying capacity, not a maximum weight per passenger. The load limit is essentially a capacity expressed as a weight measurement instead of a passenger count. In that vein, a few elevators have capacity:weight=* tags.
Should we think of these load limits as capacities for both kinds of features? If so, I wonder if it would be possible to detect which man_made=bridgemaxweight=* tags are candidates for capacity:weight=*. After all, many bridges have legitimate per-vehicle weight limits, even some footbridges.
bridge:maxweight= ? maxweight:phsyical= , or it should be interpreted as a point load?
I didn’t think about this for wheelchairs when it’s mostly designed for one user (although some might fit a caregiver pushing it?) https://wiki.openstreetmap.org/wiki/Key:platform_lift:maxweight
Not quite - many footways / paths are effectively motor_vehicle=private for vehicles used by the owner, e.g. street-sweeping and other maintenance vehicles.
I have no idea; I’m a novice when it comes to bridge engineering. The sign says “Vehicle Load Limit”. The product brochure says nothing specific about loading.
That’s true of many footbridges, but probably not this one. It would be pointless to drive over the footbridge, which runs parallel to a standard road bridge a few yards away.
Here’s another Contech bridge with a lower load limit. At less than 5 feet across, this bridge is also too narrow for a standard vehicle, as is the trail that leads to the parking lot. A motor vehicle would have to destroy a good chunk of the habitat around the trail in order to reach this bridge.
Thanks, didn’t know about that tagging scheme. How would a layperson tell the difference between rating:weight:dynamic=* and rating:weight:static=* when casually surveying a bridge? Would it be rating:weight=* until a more experienced bridge mapper is able to come along and consider it in more detail?
Would rating:weight=* also apply to an elevator load limit too? Based on building codes, these limits are usually expressed as a “capacity” by weight or number of passengers, whichever is less.
From what I found, the published load bearing capacities are static loads which already have safety margins to account for higher loads from dynamic strain.
I’d prefer rating:maxload as the tag name for what a bridge can nominally bear. Or maybe capacity:weight
I don’t want to make a new capacity:*= , but rating= is nominally defined as the apparent power procedural-wise. If load= / load:traffic= / traffic_load= (*:weight= seems to include own weight) has general applicability, it can be invented. Proposal talk:Data center technical attributes - OpenStreetMap Wiki
But for your wording, this is not “design” load, which includes safety factor. It is the operational load.
Besides, “load rating” is an exact term with a specific use. Authorities could signpost a lower load limit than the rating. There’s also “inventory rating” for indefinite lifespan, in constrast to “operational rating”.
By the way, a bridge can also have a maximum number of “users” at a time. This has the added complication that the number of vehicles is also a traffic rule. It applies to the entire length of the roadway no matter how many times the way is split.
I don’t know which kind of load this is, but from a layperson’s perspective it all sounds like the same thing as the maximum weight and/or passengers on an elevator. I’ve been tagging capacity=*maxweight=* on both the bridge area and the roadway(s) whenever I see these signs, but I recognize that it might be a different situation than the manufacturer plaques.
I would go for capacity:*=* for limitations based on a “user” count and maxload=*for a limitations based on a weight. The 30tons of the MI-sign would be a classic maxweight.
So like a elevator might have a maxload=1 and capacity:foot=15. Not sure whether foot is the best linguistic fit
I think the elevator can fit twice as many feet as persons. The passenger count is essentially regulated like a room capacity, so it would be nice if we could just keep using capacity=* for both.
maxload=* might get confused with maxweight=* when it appears on the same sign as a maxaxleload=*. On the bright side, I’ve never seen a limit specific to handtrucks.
To me, that’s a pretty good case for why maxweight=* would be a common-sense tag for it – probably what a lot of maxweight=* on footbridge areas refers to. But on the highway=footway way, I kind of like the bridge:maxweight=* suggestion, if only because a data consumer could recover from a way split by joining up the ways with bridge=yes.
On the other hand, the “load” terminology more clearly refers to a total limit rather than a limit per user.
The passenger count is essentially regulated like a room capacity, so it would be nice if we could just keep using 