Wildlife getting hit by cars is a real problem, not just for the animals but for the people in the cars that hit them. Wildlife bridges are the solution.
Millions of animals cross roadways for a good reason; mates, food, or water sources. If wildlife is forced to stay on one side of the road, this could damage diversification within the species and potentially kill them off.
Wildlife bridges, tunnels, and cannons are the solution.
Animals are smart and will avoid barriers at all costs. Oftentimes, it is even engrained in the species to always avoid certain areas because there may have been a fence or roadway there, even if it has since been removed (like the barbed-wire fence in The Czech Republic).
Humans are attempting to reeducate animals to cross over these divides by building tunnels, bridges and have even introduced a salmon cannon to help salmon get past dams.
Roadkill will always be an issue but hopefully be somewhat avoided with our help, and humans and animals can all live symbiotically on this planet.