Nearly all the roads in my district (West End, Southampton, UK) apart from motorways are tagged with #lanes as 1. The Help says the count should be the number of lanes per way. In fact most roads here have 1 lane in each direction with maybe a white line separating those lanes and they have been mapped as a single way. So surely those ways should be tagged as having TWO lanes? The same for residential roads. Am I missing something?

asked 11 Feb '13, 18:05

griggy's gravatar image

accept rate: 0%

It appears to be a bug with Potlatch 2. It seems it showing roads minor roads as 1 lane, or major roads as 2 lane, even if they are not tagged with the lanes.

If you switch to the "Advanced" tab in Potlatch 2, you can see what tags the roads actually have. Or go to, and enable the "Browse map data" option. Checking that area of Southampton, most roads do not have a lanes tag.

This problem has been reported on Trac, but not fixed yet:

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answered 11 Feb '13, 20:14

Vclaw's gravatar image

accept rate: 22%

That's correct, the roads in your area seem to have been tagged wrong. The number is the total number of lanes. A typical residential road has two lanes and a typical residential oneway road has one lane. Also see the examples in the wiki.

Don't forget to contact the author to tell him/her about the mistake.

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answered 11 Feb '13, 18:45

scai's gravatar image

scai ♦
accept rate: 23%

Maybe where you live a typical residential road has two lanes, but that is definitely not the case around here. Here most residential roads have no line in the middle and thus have only one lane.

If I read the question right there are mostly no lines in the middle of the road in Southampton, so they are mostly tagged right.

(11 Feb '13, 23:37) cartinus

It doesn't matter whether there is a visible line in the middle or not. Look at the third example picture. The physical width is more important. Here in most smaller cities residential roads also don't have a white line in the mittle. Nevertheless they have two lanes - one for each direction.

(12 Feb '13, 06:03) scai ♦

Actually that third example is complete nonsense. On a rural road of 4 meters wide two normal cars engaging each other will have their wheels on the passenger side on the shoulder. Unless the drivers are completely reckless they have to slow down too. I think you will have a hard time finding a road builder that calls that a two lane road.

(12 Feb '13, 10:47) cartinus

You have a case that just "no lines" doesn't make it a one lane road. But minimum (recommended) lane width in Western Europe and North America is somewhere between 2.5 and 4 meters depending on the country/road type/traffic type. Most of the places where you don't see a painted centre line is because the road is actually narrower than twice the minimum for a lane.

Looking at "West End, Southampton, UK" with Google Streetview, most of the residential roads appear narrower than 5 meters.

(12 Feb '13, 11:38) cartinus
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question asked: 11 Feb '13, 18:05

question was seen: 2,302 times

last updated: 12 Feb '13, 11:50

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