From Gizmodo:
These Incredible Man-Made Highways Are Built Just for AnimalsQuoteHumans don't exactly have a stellar record when it comes to environmental stewardship, but that doesn't mean we aren't trying. Numerous projects around the world are working to rebuild lost habitats, protect vital wildlife highways, and regenerate lost populations. Here are a few man-made structures built on behalf of our four-footed brethren.
FULL ARTICLE HERE (http://markholtz.info/og)
Uh, these highways are not built just for animals. Over- or underpasses are provided on highways built for people.
PS: "a heard of cattle"
Scripps-Poway Parkway in Northern San Diego has a tunnel system near it's eastern terminus with CA-67. It even has a solar tube system to illuminate the inside during the day, you can see the tops of the light admitting structures in the median.
"Alligator Alley" is in Broward and Collier Counties, but not Lee County. Besides, most of the panther strikes were on FL 29 and US 41, since the Alley was widened between '90-'93.
The new Tamiami Trail bridge is quite amazing in scope, even though it's a single long span.
AAA thought Alligator Alley was being built just for gators. Hence the name.
North of here they've started putting in culverts for bears.
The new section of I-69 in south Indiana has an approximately 4400ft long bridge with run off collection to limit disruption of the Patoka River and associated wildlife reserve.
http://www.aspirebridge.com/magazine/2013Spring/I-69TwinBridgesOverThePatokaRiver.pdf (http://www.aspirebridge.com/magazine/2013Spring/I-69TwinBridgesOverThePatokaRiver.pdf)
Similar to the cattle tunnel in the article, US 50 west of Shoals, Indiana, has a box culvert the farmer is allowed to use as a cattle tunnel. It's probably not uncommon.
Those are provided not only for livestock, but also to allow the farmer to get his machinery between the halves of his field, without a long haul to the nearest overpass. They are not uncommon.