Exit number and Destination Mapping Guide

What are exit numbers?

• An exit number is a number assigned to a road junction, usually an exit from a freeway. It is usually marked on the same sign as the destinations of the exit, as well as a sign in the gore.

Different tags for exit numbers:

• ref=* is used when the exit has a specific number assigned to it.
• noref=yes is used when the exit doesn't have any official number assigned to it.

How to add exit numbers?

• Open checkautopista2 and zoom to the assigned state. In the search tab (top left corner) click on search in map button to load all the visible highways in the bounding box.

• Select the assigned highway from the dropdown and click on the download button.

Verify the exits on the route for missing information

• Load the route in JOSM

• Browse along the route and check the ways on both directions at every exit location for the following:

• There is a motorway_junction at the start of every motorway_link exiting the highway
• The motorway_junction has a correct exit number ref value as per the source.
• The exit number on both directions are the same
• There is only one exit in a direction for every exit number

Add missing exit numbers

• Download the data and mapillary layer to locate a signboard around the blue marker in the imagery.

• Use a combination of Mapillary, Department of Transportation (DoT) documents and Wikipedia to add the ref=* tag on highway=motorway_junction (stick to using Mapillary and DoT doc as primary source and move to others in case of unavailability of information)

• If it is confirmed there is no exit number for the motorway_junction add another tag noref=yes to indicate the exit does not have an official reference number.

Analyzing signboards in mapillary

Look out of Highway sign boards on imagery. They may look something like this-

Places to look for-

• near a motorway_junction
• near start of a motorway_link

Do's and don'ts

• It is not necessary that exit numbers are sequential. It might find 45 after 41.

• There are some motorway_junction which don't have any associated exit number. Add noref=yes on these nodes.

• If there are multiple exits on the same signboard then you can tag them as ref=* ; * instead of ref:left=* and ref:right=* until you are confirmed with that.

• In the case of discrepancy between mapillary and DoT document, look out for the recent change in exit numbers on the web. Many states changes/in a process to change the exit numbers.

• Ignore the highway=motorway_junction where the traffic flow is towards the motorway

What are destination tags?

• Destination tags describe the content of signposts or ground writing indicating the names of the locations that a certain exit from the freeway or a highway is heading to.
• The key destination=* describes where a certain exit leads to. Thus navigation systems can refer to road signs that the driver actually sees.

Different tags for destinations:

• destination tag refers to the place that the way exiting from the freeway leads to.
• destination:ref is the reference of the roads directly ahead.
• destination:ref:to is to specify the reference of a major highway ahead.
• destination:street refers to the main street the way exiting from the freeway leads to.

How to add destination tags?

Assign a highway and use Checkautopista2 to map features

1. Open the destination reference document for your assigned city area. Pick a highway to check and assign it on the spreadsheet to avoid conflict.

2. Open checkautopista2 and zoom to the assigned state. In the search tab (top left corner) click on search in map button to load all the visible highways in the bounding box.

3. Select the assigned highway from the dropdown and click on the download button.

4. Look out for red outer circle for missing destination. Use open in JOSM button to open the node in JOSM. Orange outer circle represents exit_to tag and we don't need to add destination tags in the way. Green outer circle represent that the concern way already has destination tag.

5. Download the data around the motorway_junction and mapillary layer to locate a signboard.

6. Use combination Mapillary images, DoT documents, and Wikipedia to add destination as destination=* on motorway_link ways and the destination highway as destination:ref=*. Below is a an example On the highway=motorway_link(represented by red line) add destination=Daly City and destination:ref=I 280 South. This can be confirmed with DoT document and wikipedia while searching for exit number 431

7. Add any highway missing in the highway spreadsheet. Mark the highway done if all destination tags are mapped/review

Analyzing signboards in mapillary

Look out of Highway sign boards on imagery. They may look something like this-

Places to look for-

• near a motorway_junction
• near start of a motorway_link

Do's and don'ts

• Use ; to separate multiple destination and refs.
• Read more on Highway intersection to understand them better.