Talk:Proposed features/mark vehicles, for which restriction is operating

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Wouldn't an access tag on the roads that are prohibited make more sense? If a certain type of vehicle is not allowed to make that turn, they probably aren't allowed on the street, other than a u-turn. --Panther37 17:26, 8 July 2011 (BST)

This is not always the case. A no_left_turn is in most cases only for motor vehicles, bicycles (and certainly pedestrians) can still turn left if they cross the road twice. I am for this proposal. --Sanderd17 18:34, 8 July 2011 (BST)
That's not always true. In Hilliard, Ohio, trucks are permitted on Cemetery Rd and Scioto Darby Rd, but they are not allowed to turn right from Scioto Darby to Cemetery. I wasn't sure how to tag that, but I went with type=restriction + restriction:hgv=no_right_turn + description=Trucks: no right turn. That of course was before I saw this proposal; however, I'm not entirely sure the proposed tagging is the best, as noted below. I can also cite, on the other hand, an example in Grove City where signs indicate that trucks can't make certain turns, but that apparently is a side-effect of trucks being prohibited on a particular street as Panther37 suggested is true in most cases. When that is in fact the reason classes of vehicles can't make a particular turn, then indeed it's better to simply set the appropriate access=* tagging on the appropriate street, but that's not always the case, hence the need for this proposal. Vid the Kid 18:38, 8 July 2011 (BST)
We can divide reasons for restrictions of some actions for some type of vehicles to 2 types:
type 1: there is a restriction of access for some type of vehicles on the road. In such cases, of course, it is better to put access tag to the road and not to put restriction tags to crossings of this road.
type 2: there is a restriction of some action for some type of vehicles on the concrete crossing. For example: transport committee of some town doesn't want to see large vehicles turning in some crossing, because opposite car traffic is rather big, street is rather narrow and large vehicles, turning left, can make traffic jams. So we see File:4.1.4 (Road sign).gif8.4.1 (Road sign).gif. Large vehicles can use the road on the left, but they can't turning left to it in such crossing. Another example: a crossing of road with big traffic of tourist buses and small road, that goes to place of interest. If bus turns right to small road from the bigger one, there are problems, because there is no such place to this action. So we see: File:4.1.5 (Road sign).gif8.4.4 (Road sign).gif.
In my proposal I say only about such places, where using of some road is allowed, but some action in concrete crossing of this road is prohibited. If full road is prohibited for some types of vehicles, it is better to use access tags on the road. Dinamik 18:40, 8 July 2011 (BST)

Using the access=* tag could still do the same thing in the relationship. If you look under Transport Mode Restrictions you could have access=vehicle_type, that would give just that vehicle type the restriction. However that would be a double negitive and is confusing. You could also have access=yes,vehicle_type=no but that is equally confusing because you are giving all others access on a restriction but seems less confusing. I'm not quite sure that for=* is the right tag but I like that more than restriction:vehicle_type=*. only=* comes to mind but is not more elegant. ref=* also comes to mind but I thought that was supposed to be for numbers. I looked to see what is done with maxspeed=*. It uses maxspeed:vehicle_type and all other types of maxspeed:variable=* so I think this should match that and use Variant II and retire requesting to use access=*. --Panther37 20:57, 8 July 2011 (BST)


I think that 8.4.2 (Road sign).gif would be better called "trailer" or sth. similar. It has nothing to do with hgv, but is valid for all kind of trailers (1 and more axis). --Dieterdreist 02:59, 11 July 2011 (BST)

I agree. Originally I wrote "trailer", but saw tag "hgv_caravan". Let it be "trailer". Dinamik 12:11, 11 July 2011 (BST)
caravan=* is already used in access=* and is described as "needs to be towed by another vehicle which has its own restrictions." I think we should try and stick to convention and have hvg_caravan be just caravan. --Panther37 02:24, 12 July 2011 (BST)
I changed trailer to caravan. Dinamik 12:43, 12 July 2011 (BST)

Backwards Compatibility

The tagging as proposed has a problem with backwards-compatibility. It proposes a new tag on relations, for=*, which limits the scope of an existing tag, restriction=*. Software that is not familiar with this change would misinterpret turn restrictions that are tagged this way. On the other hand, such misinterpretation would tend to err on the side of caution, with very little chance of directing a vehicle where it's not supposed to go. The alternative would be to prefix or suffix the restriction=* key with the type of vehicle to which the restriction applies (example: restriction:hgv=no_right_turn). That way, software unfamiliar with this change would simply ignore the restriction, which would be correct for most traffic. The downside is such software could then direct traffic where it's not supposed to go. So I guess it's a choice between a minor error / inconvenience for most (as proposed) or a significant error for few. Vid the Kid 18:38, 8 July 2011 (BST)

Alternative proposal

Your initiative has inspired me to publish a similar idea of mine as a proposal today:

Proposed features/Conditions for restriction relations

It also handles the situation that a restriction only operates at certain times or days much better than hour_on/off (which only allow a single time interval), and can be extended to support even more situations if it becomes necessary. What do you think of it? --Tordanik 20:19, 8 July 2011 (BST)

I'd like to at least understand the reasons for the differences between our proposals exist before starting a vote for either proposal, so I'd appreciate some reaction from you. I think that your proposal has at least the following shortcomings:
  • You cannot express time-based restrictions using your suggestion, and this feature cannot be easily added in a manner that is consistent to your syntax for vehicle restrictions.
  • The "restriction:*" variant works for type=restriction relations, but it's not necessarily possible to use the same idea for other relations. That might be enough for now, but why not choose something future-proof that would also work well if we ever express other restrictions as relations?
Do you acknowledge these as disadvantages? What are, in your opinion, the advantages of your proposal? --Tordanik 17:35, 20 July 2011 (BST)
  • I don't think, that your proposal is bad, I don't know, when are you planning to propose it (for voting):). If you are planning to do this in the nearest few weeks, I will not start voting, until your proposal will be considered. Dinamik 01:03, 21 July 2011 (BST)
I'm still trying to get some more feedback (for example in the forum), but if no major problems are reported, I'm going to start the vote for my proposal later this week, probably on Saturday morning. Is this ok for you? --Tordanik 09:40, 21 July 2011 (BST)
Yes, it is normal. I said about my doubtfuls, because I saw proposals, which are staying in status "draft" or "RFC" for a few years. Dinamik 12:47, 21 July 2011 (BST)