Watching the flashing "Turtle Crossing" warning signs on Cootes, I remain skeptical about the effect on traffic speed.
The only thing I've seen that actually slowed traffic along here was when the lanes are reduced to half capacity, and moved to one side of the centre median (see video). This temporary road engineering creates conditions that strongly discourage speeding, and I think it would be a much-needed safety improvement on the regular divided highway layout.
Such a roard treatement would also have the added benefit - if we truly want to help turtles survive - of decreasing the crossing distance for wildlife by well over half the current road width.
The best solution likely remains temporary road closures during turtle nesting times, as the city of Burlington does for Jefferson Salamanders on King Road. As long as the closure is well advertised in advance, drivers could adjust their trips accordingly.
We will watch to see what emerges as an effective protection to the turtles (and other wildlife) in Cootes Paradise.