On 23 April 2012 12:05, Martin Koppenhoefer <[email protected]> wrote:
> Am 22. April 2012 16:43 schrieb Jason Cunningham <[email protected] > >: > > 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 less been replaced by hatchbacks & 4x4's. If we look at best selling 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 info) 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. Jason
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