[Talk-us] User randomly adding speed limits across the US

[Paul Johnson]

On Mon, Dec 1, 2014 at 11:41 AM, Clifford Snow <clifford at snowandsnow.us>
wrote:

>
> On Mon, Dec 1, 2014 at 8:05 AM, Paul Johnson <baloo at ursamundi.org> wrote:
>
>> Entering most counties you get a sign that's printed in FlySpeck 3 font
>> that reads:
>>
>> Unless otherwise posted speed limit
>> 35 MPH
>> on all roads in Lincoln County
>>
>
> I wonder if adding default maxspeed to the city admin boundaries would be
> an easy way to post these city/county limits? The alternative is to add the
> maxspeed to every highway segment in a city.
>

No, I don't think so.  The individual ways seem to be the way to go,
especially for editors, since (at least in Oklahoma), posted speed limits,
as compared to miles available (as opposed to miles with traffic volume)
are relatively rare.  It also obviates when you find a posted speed limit
in an area that's otherwise default.  This also greatly improves the
quality of the data (even if you're bulk tagging an entire county, this
correctly sets the speed limit for well over 90% of lane miles in the
county, and gives a reasonably sane assumption and obviates issues inside
city limits and on state highways (which often have lower zone and
sometimes higher explicit; and generally higher explicit limits
respectively).

For data consumers, tagging a boundary for zone limits ends up requiring
the consumer to be geographically aware of the location well beyond the
nearest object or the way being traversed longitudinally, which becomes
problematic in itself.

Of course, Oregon doesn't quite have this problem, ZIGZAG
<https://zigzag.odot.state.or.us/>, among other things, has speed orders
for *every* public way that has a non-default speed limit, as ODOT has
exclusive rights to set speed limits on public property in Oregon (and in
the off chance that there's no speed order, then the default speed limits
apply, which I've covered many times in the past and are also published in
the driver's manual (and I seem to recall, tested against in the driver's
test, as the only question I got wrong was how much faster an ambulance
with it's lights and sirens on is allowed to travel over the speed order
(turns out the answer is 10 MPH over, but good luck finding a cop willing
to pull over a responding ambulance).  This is all public data under the
Oregon Sunshine laws, and if someone were to do the lookups and conflation
work, it would be possible to get exact speed limit information for every
way open to motorists in Oregon that isn't private property.
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