Talk:Proposed features/motorway junction Extension

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Great idea

I'm adding all the interstate exits in Virginia, and have definitely come across this situation on many occasions. I've already started using it, as it's the only way to indicate the exit number of each part of the split. It might be a little tricky for data consumers (routers) to figure out whether to use left or right (but not impossible), wondering if perhaps a relation might be a more robust way to handle this. I'd like to see more feedback from others. -- Joshdoe 04:01, 9 June 2011 (BST)

Can you provide some examples of where you've done this already? I can then add them to the front page of the proposal. ;) I agree that I wished more people would have commented on this. Only one person even replied to the post to the tagging list about this proposal. However, this proposal is pretty straight forward that people think it's fine as is and are just waiting for the vote (I hope). :) -- rickmastfan67 06:35, 25 June 2011 (BST)

Are left and right needed?

I agree with identifying which how a motorway exit splits, but instead of having separate 'left' and 'right' tags, could both exits be included in the same tag?:

would become (note: exits are entered left-to-right)
Better Example
Exit with that splits into three:
Left goes to the 'A1 Here' and 'A2 There'
Middle goes to 'A30 Somewhere'
Right goes to 'B20 Nowhere' and 'C6 Elsewhere'
would become (note: exits are entered left-to-right)
exit_to:=A1 Here;A2 There,A30 Somewhere,B20 Nowhere;C6 Elsewhere

This way the same tag could be used for a single non-splitting 'exit_to' or multiple splitting 'exit_to's (I can think of real-life examples with 3 or 4 different exits). It would also make it easier for routers.--mso 00:36, 07 July 2011(UTC)

Arbitrary conventions like listing left-to-right don't really work. In your example, many mappers would assume 1B should be before 1C. --NE2 15:24, 7 July 2011 (BST)
I agree with NE2. Sometimes DOT's flip exit numbers (letters) around and put them in an incorrect order. Plus, I don't know if you saw the "additional uses" section, mso. Without the :right and :left additions, how would you or the routers tell which segment of "motorway" the exit number and exit_to info would go to? With the I-77/I-74 example, we have a multiplex of two Interstates splitting. While a person who's traveled that segment of highway knows that I-77 is the main highway there, another person might assume that I-74 is the primary since it's the lower numbered Interstate. Heck, even looking at the map it looks like I-77 is the exiting Interstate, but it's I-74. Here's an example of how MapQuest deals with that interchange in it's directions: They just say I-77 becomes I-74 at the exit, which isn't correct as I-74 is multiplexed with I-77 from the Virginia border. The step should also mention the Exit #101 in it (but that's another story and MapQuest acknowledged that they have a bug right now that prevents any exit number from being shown). Still, once they do fix the exit numbers, they might not mention it for I-74 leaving because they wouldn't know which Motorway to give it to, hence the need for the :left/:right tags to help out. -- rickmastfan67 14:27, 8 July 2011 (BST)