Low bridge rails can put some bird species at risk of flying into traffic, and bright lights on bridges can slow the passage of some fish species. Clay, sand, and other sediment suspended in water during bridge construction can also kill aquatic organisms or degrade important aquatic habitat. The runoff from bridges caused by traffic and maintenance activities can adversely affect aquatic organisms, too, when pollutants enter the water in sufficient concentrations to do harm. And some wildlife species are sensitive to disturbance resulting from bridge and road construction work in their vicinity.
Here are some things state transportation agencies have done to prevent these problems from occurring: