highway - n. a main road that connects cities, towns, etc.

elk - n. a large kind of North American deer with big antlers

salamander - n. a small animal that looks like a lizard with smooth skin and that lives both on land and in water

traffic - n. all the vehicles driving along a certain road or in a certain area

arch - n. a usually curved part of a structure that is over an opening and that supports a wall or other weight above the opening

commerce - n. activities that relate to the buying and selling of goods and services

endangered - adj. used to describe a type of animal or plant that has become very rare and that could die out completely

pronghorn - n. a large animal of western North America that looks like an antelope

obstacle - n. something that makes it difficult to do something