[Tagging] Dispute prevention: meaning of lanes tag

Jason Cunningham jamicuosm at googlemail.com
Mon Apr 23 14:03:05 BST 2012

On 23 April 2012 12:05, Martin Koppenhoefer <dieterdreist at gmail.com> wrote:

> Am 22. April 2012 16:43 schrieb Jason Cunningham <jamicuosm at googlemail.com
> >:
> > I've had a look for uk guidance as the uk's ordnance survey was
> mentioned,
> > and a lot of older uk advice appears based around a now historic view
> that
> > 'cars = saloon cars' and were 1.8m or less. If cars were assumed to be
> 1.8m
> > wide then implied OS figure of 4m for two lanes makes sense.
> >
> > But saloon cars are no longer the 'standard' car, in the uk they've more
> or
> > less been replaced by hatchbacks & 4x4's. If we look at best selling
> cars in
> > the UK (and I assume Europe) we have to assume car widths (with mirrors)
> are
> > now just over 2m, which I'd round up to 2.1m.
> -1, fortunately this isn't true and cars are usually not larger then
> 1.8 metres, actually the best selling cars are usually smaller than
> that. E.g. have a look here (I didn't check it extensively, but I
> guess it is true):
> http://en.wikipedia.org/wiki/User:DeLarge/Top_10_best_selling_cars_in_Britain

What I said about car widths is true. A quick search confirms the current
models of the 'Ford Focus', 'Volkswagon Golf' and ' Vauxhall Astra' are all
wider than 2m (common width for these type of "family" cars appears to be
2.010m). Note that I said "with mirrors". The wing mirrors can be folded
back to make the cars narrower, but you don't have your wing mirrors folded
back when driving.

> Anyways, I think researching the average car width shouldn't be
> required for mapping lanes.

That's a fair point. But my response about car widths was meant to be
linked to the solution Martin Vonwald is suggesting for narrow 2 lanes
roads currently being tagged as lane=1.5 (a tag not documented but being
used for roads that two cars can pass at a crawl, and clearly important
Martin implied the wiki should suggest not using the lanes=1.5 but instead
people should use lane=2; width=4 (or est_width=4)
What I was trying to point out, and maybe should have made clearer, is that
I thought suggestion was acceptable in principle, but that width=4 was
wrong. Common cars now have widths greater than 2m, I felt Martins
suggested advice for dealing with lanes=1.5 should be lanes=2, width=4.3

Problem with that, and why I am said this is far more complex than I first
thought, is some people responding to lanes=1.5 by saying 'computers' only
like whole numbers. This suggests width=4.3 would need to be rounded to
either width=4 or width=5 neither of which would help with solving the
lanes=1.5 problem, because 4m is to narrow for two 2.010m cars, and 5m
arguably doesn't require you to significantly slow down.

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