[Imports] "fleet manager" speed limit import proposal (Canada, USA)

Saikrishna Arcot saiarcot895 at gmail.com
Wed May 7 19:22:54 UTC 2014


For the record, 121 km/h is 75 mph. I think Texas and New York (at least) have these speeds.

-- 
Saikrishna Arcot
On Wednesday, May 07, 2014 02:45:52 PM Richard Weait wrote:
> Dear imports@
> 
> A followup on the fleet manager max speed data.
> 
> So far, I have explicit permission for using the data in OpenStreetMap
> from the publisher.  I hold the test file, nobody has yet imported any
> of the data.
> 
> Some new items.
> 
> On various lists / direct email, I've had technical suggestions that:
> 
> - We use an identifier for the submitter of the data.  So that we can
> learn to trust one driver or another, more or less.
> - We get a time stamp, or osmid version number with the way number, so
> that we know that we are looking at a way that is unchanged since the
> maxspeed report.
> 
> Both are fair enough as technical suggestions.
> 
> I would describe the community response as "cautious optimism".  So
> far no suggestions that the data is unwanted or inappropriate.  Most
> of the questions are around, "how can we best use this data?" and
> "sure.  better speed limit data sounds good."
> 
> I've also looked at the data in more detail.
> 
> 1) While I initially thought the data was limited to Canada / US, that
> is not the case.  The data is worldwide, as the fleets involved are
> international.  That's good and bad I suppose.  :-)  More communities
> to get on board for us to proceed, I guess.  On the other hand a
> country by country roll-out will probably help to limit negative
> effects.  :-)
> 
> 2) I expected the data to be entirely sensible and reflect the posted
> speed limits.  I was surprised to find that some of the speed limits
> are off-by-one of what I would expect.  Here is a summary of the km/h
> data only, shown as number of reports followed by km/h value
> 
>       1 30
>       1 35
>       1 40
>      24 50
>      32 60
>      18 70
>     164 80
>       4 90
>      14 100
>       2 121
>       8 130
> 
> see that "121"?  That surprised me.  I don't know for sure that it
> isn't on a sign somewhere, but still. :-)
> 
> We could campaign for more warnings for the submitters to only include
> actual signed values.  These could also be typos.  We could drop data
> like this as unreliable, do something else with it.
> 
> Next steps:
> 
> I'd like to look at the data in more detail.  The current format
> (way_id and max_speed) isn't ideal for a slippy map overview, so I
> added a few wayids to a slippy map with overpass.  Could you suggest a
> nice way to do this so that I get 1400+ ways on a slippy map, without
> hammering the edit api?
> 
> And from there, I'd like for some other mappers to take a look and
> sanity check the data in their areas.  Perhaps by backing it up with a
> ground survey.  Of course, I don't yet know where there are enough
> items in an area to make it worthwhile.  So perhaps a visualization
> first.
> 
> best regards and happy mapping,
> 
> Richard
> 
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