The real problem is that yellow signal timing standards have been weakened.
thenewspaper.com covers the weakening of the standard here
Essentially, yellow signal timing needs to take into account human reaction time, the actual speed that traffic goes through an intersection, and time needed to clear the intersection. In 1976, the standard did.
1985 and 1989 revisions to the ITE standard made changes:
1989 standard: "It may be possible to use the posted speed as the approach speed." - Posted speed limits, as opposed to the actual speed that traffic goes through an intersection could be considered for setting yellow signal timing.
There are other changes detailed that impact yellow time.