Cable or wire rope barrier was being used in the 1940s and maybe earlier for vehicle containment. Through the years the designs have changed, but engineers continue to see cable barrier as an inexpensive barrier for use in some roadside applications. Recently, cable or wire rope has gained popularity as a median barrier for the prevention of cross-median accidents. Cross-median accidents are typically violent collisions with a high probability of multiple serious injuries and deaths. Thus, the design trend is gravitating toward providing positive vehicle containment in wider medians for which barriers have not historically been warranted. Wire rope often provides a cost-effective solution for this design scenario. Field experience with cable or wire rope barriers has identified areas for design improvement. It is desirable that cables remain taut to improve interaction with the vehicle, reduce dynamic deflections, and minimize maintenance. Additionally, reduced design deflections result in more potential application sites. Recent research demonstrates that such improvements are practical and cost-effective. Besides the initial tension in the wire ropes, other factors that can have a significant influence on dynamic deflections include post spacing and horizontal curvature. Computer simulations with cable barriers with various post spacings and horizontal curvatures were used to develop guidelines for expected design deflections. Finally, full-scale crash tests were completed with a new, cost-effective cable terminal system, and a brief review of the design and crash test results is included.