Here is a before/after study ( Download Elm Creek Blvd Ped Crossing Study) we just completed studying the effectiveness of a new push button activated, LED lit pedestrian crossing sign (thanks to Marc Culver at the City of Maple Grove for letting me share this with you). We collected data (from video) for 12 hours on two days before and two days after the sign installation (48 hours total of data).
The hope is this type of sign would cause vehicles to yield to pedestrians more frequently than with the standard crossing signs. Unfortunately, we found negligible difference in vehicles yielding to the pedestrians with the new signs compared to the yielding at the old signs.
BUT, that was largely due to only 7 pedestrians pushing the button in the after condition (and 5 of those could cross without any cars coming). The punchline is that we don't know if these LED lit signs cause vehicles to yield more frequently to pedestrians (compared to typical pedestrian crossing signs) because pedestrians don't push the buttons to turn them on.