RESEARCH - Safety Evaluation of Pedestrian Countdown Signals
Here's a document from the US Federal Highway Authority that looks at the safety benefit of pedestrian countdown signals. The study results showed that after the implementation of these signals, pedestrian crashes decreased by 9 percent, total crashes decreased by 8 percent and rear-end crashes decreased by 12 percent.
The new BC Active Transportation Design Guide speaks of these signals starting on page G34. The guide says that:
With pedestrian countdown timers, people crossing are aware of how much time they have to cross the road.
This is not strictly true as it really only counts the time to the end of the green phase. If a pedestrian enters an intersection controlled by signals during the walk phase, they are required to proceed as quickly as possible during the don't walk phase if it occurs while they are crossing. If this happens they still have the right of way over all other vehicles to complete crossing. Section 132 MVA refers.