One of the most serious failings of the DEIR is that it claims that effects on wildlife can be mitigated to insignificance. This is happening because such mitigation is either not possible, or rarely carried out. Added lanes on highways are not insignificant. Speeds are increased, and the probability of safely crossing is drastically reduced. Humans understand freeways, and still are often killed trying to cross them.
Animals have an even harder time.
And there is no recognition in the DEIR that the mere presence of a road can present enough of a barrier to a species that it will refuse to cross it, and become extinct due to inadequate genetic diversity. It is dishonest, and biased toward maintaining the status quo.