Often mounted on crash barriers at window level, they are placed along roadsides at choke points where vehicles must slow down, such as intersections and junctions.
The network of stargates, which allows travel between star systems, includes a multitude of choke points, which careful alliances can garrison to restrict access to claimed null-security systems.
Sections of less accessible codons that slow ribosomal transaction are known as choke points, and sections of easily accessible codons which result in faster ribosomal transaction are slippery sequences.