It doesn't follow that because the number didn't go down, that means the efforts did or didn't help. You need to think of the overall picture, are there other factors causing it to increase and would the number have been even higher without these efforts? The simple fact of the number not going down, doesn't really say much.

Have they had better luck with wildlife crossings since 2016?

https://transportation.libguides.com/c.php?g=849313&p=607536...

Slowing speeds would work