I recently received an interesting request and I'd like to know what solutions the community might suggest. I should probably also state that I couldn't come up with a workable solution which annoys me hence this post.
The request was to portray historic traffic data on a map, particularly at intersection in order to view which intersection were leading to long wait times. Sounds simple enough on the face of it. However, given the focus on intersections it was important to delimit the data by lane (left turn, through traffic, right turn). As far as I can tell the only freely available road data for the contiguous US comes in vector line format giving no width nor distinction between lanes.
Does anyone have any potential solutions as to how to map this? I drew blanks and cycled through various notions including, symbology, cartographic representation and creating new features for each lane at each intersection. None of which turned out to be that practical. In addition, the intersection location is ostensibly point data and so symbolising four different directions (based on many potential combinations of flow data) didn't seem practical either.
If anyone does have any ideas I'd really like to hear from you.