Silt. Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body. It may also exist as soil deposited at the bottom of a water body.
In North America, a grade-separated junction may be referred to as a grade separation or as an interchange â in contrast with an intersection, at-grade, a diamond crossing or a level crossing, which are not grade-separated. 1 Effects.
The logic was simple: The more sides a sign has, the more dangerous the upcoming stretch of road is. Circles (which were considered to have infinite sides) designated the riskiest hazards, like railroad crossings. Octagons denoted the second most perilous hazards, like intersections.