There are over 4.1 million miles of public road ways and over 3.5 million miles of streams in the US according to the Bureau of Transportation Statistics and the US Environmental Protection Agency. At each road-stream crossing, there is not only a potential barrier to safe and efficient traffic on the roadway, but also a potential barrier to safe and efficient aquatic organism movement under the roadway. Culverts that act as barriers disrupt the movement of organisms or material (sediment) through a culvert and may affect the habitat conditions upstream and downstream of the culvert with excessive scour or deposition. In general, fish passage issues arise if conditions near or within the culvert are significantly different than the stream habitat outside of the culvert's influence. This research combines a series of experiments conducted in the field and at St. Anthony Falls Laboratory (SAFL) at the University of Minnesota to examine the design of box culverts for fish passage. Our projects examine three key aspects to design for fish passage through box culverts: a) potential behavioral barriers (light), b) sediment transport in embedded culverts (a key component to predict habitat conditions), and c) performance of methods to add roughness along the boundaries of concrete box culverts. Results from these experiments provide guidance to culvert designers on a) potential light mitigation strategies, b) the need for sediment placement within embedded culverts, and c) the feasibility of inexpensive culvert retrofits for fish passage. These experiments focus on Minnesota culvert design, but lessons learned are applicable to other locations with similar geomorphic characteristics and fish communities.