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Within ArcMap, I have a point dataset representing accident data, and a road dataset. My goal is to attribute the road dataset with a count of how many particular accidents occured on each road segment. I can't however figure out how to produce a count of point/line intersections. I have tried a spatial join using 'one to many', however this doesn't produce a count, just multiple lines for a road with more than one accident. I've also tried a intersect, however ArcMap has told me this is not possible.

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Right click your road file, joins and relates > join.

Select join data from another layer based on spatial location in the first dropdown box.

Choose your point layer in the second dropdown box as the layer to join to the line layer.

Select "each line will be given a summary of the numeric attributes of the points that are" then select "intersected by it" below that.

Your new shapefile will have a "count" field added to it representing how many points intersect that line.

Join one to many

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This post by ESRI helped me- It uses the example of polygons instead of points. I had buffered my accident points, as some were not quite intersecting the roads. If you are trying to do this with points then I would recommend doing the same. http://support.esri.com/technical-article/000008599

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The question is old but I find useful to add that sometimes you need a 'unique' count of points so the final field sum is equal to the number of original point data.

This happens when there are points that are placed in intersections, so they are added to all the street segments in that intersection.

What I do is to first make a reverse join, that is to add the nearest street data to each point (so I have a street ID or any kind of unique street identification field data per point), the I do an aggregate of this new feature on the street ID with a count of records as a result of the aggregation. Finally I do the join pointed here but between the street data and this new street-ID-aggregated point data.

Hope this helps

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