In the infancy of video detection (about 20 years ago), traffic engineers found many good reasons to not try video detection. Detection quality was iffy. Far detection and stop bar detection at the same was impractical.
Move forward 20 years, the Vector camera system is the delivery of that long-awaited promise. Here, in one camera package, replace all detector loops - stop bar and far detection - with one video package! And it's for real this time!