Imagine you are driving down a highway with your car guidance giving you the instruction “In two miles, take exit number 164A and follow the signs towards Dearborn Street” using OpenStreetMap data. This will soon be possible with upcoming improvements to the OSRM guidance engine that will use destination tags more intelligently from the map data.

Over the last week, the Mapbox data team reviewed freeways in 30 cities across the United States to find gaps, in exit number and destination information that could be improved using Mapillary images and official documents. We want to share our findings here and welcome your feedback on our approach, use of tools, and workflow.

Our Approach

We stuck to reviewing motorways and motorway junctions, as we did during mapping destination signs for 9 US States, and covered 328 motorways in total. As part of the review, we used Mapillary imagery, official Department of Transport data, Crosscountryroads, Aaroads, and Wikipedia for reference. For identification of exit numbers and destination tags, we relied on Checkautopista2 by k1wi.

Quickly find motorways with missing exit numbers and destination tags using Checkautopista2

Here is how we went about tagging:

• on nodes with motorway_junctions:
• ref=* representing exit numbers.
• noref=yes for junctions with no exit numbers.
• on ways with motorway_link:
• destination for city, neighbourhood.
• destination:ref for reference-number of next motorway.
• destination:street for streets and road.

We used this workflow for adding Exit Numbers and Destinations.

In total, we added 761 tags on the 328 motorways we reviewed. Here is a full breakdown of the number of destination related tags that were already present on OpenStreetMap before 1st April in 30 cities and what was added during this project:

Note There were already 2653 nodes with exit_to tag in these cities, which is an older tagging scheme for destination mapping (read more). These features were not modified.

As we worked on this project, we got a ton of help from OpenStreetMap contributors who provided feedback, caught mistakes, and helped us improve our process. As remote mappers, its important our edits are validated by local mappers, feel free to review the data in any of the cities that were worked on and post your feedback on our project tracker. You can look forward to more updates to the map in these cities as we work towards a more navigation ready OpenStreetMap.