"Synthesis of the performance of portable concrete barrier systems"
A report prepared for the NCHRP Transportation Research Board. A comparitive analysis of mutlpie concrete safety barrier systems.
J-J Hooks is mentioned as a favored system (reference pages 60, 61, and 65).

Concrete Barrier Walls (like J-J Hooks) are more cost effective than alternative types of barrier. Other barrier types must be replaced whenever an impact occurs (even low-energy impacts), because they may not perform properly in subsequent impacts. Considerable time and cost must be spent maintaining other barrier types, endangering motorists and workers during each repair.

jj types 1

Concrete Temporary Barriers (J-J Hooks):

  • Greatly improved safety for workers in construction work zones
  • Concrete highway barriers are the preferred temporary barrier
  • Provide a high level of containment
  • Relatively inexpensive compared to other barriers
  • Can be free-standing, bolted, or pinned
jj types 2

Steel or Water Temporary Barriers:

  • Sometimes used on low speed short-term projects for ease of use and relocation.
  • Don't provide the level of protection as concrete barriers
  • Cost more for long term projects than concrete barriers
jj types 3

Impact Deflection Barriers

  • Guard Rail is a good example of this type
  • Deflects a vehicle & keeps it moving in its original line of travel
  • Can cause the operator to further lose control of his vehicle upon impact
  • Vehicle may penetrate or be deflected over the barrier
jj types 4

Impact Absorbing Barriers

  • Simple types range from post/cable, concrete barriers, to live plants
  • More elaborate barriers include the "California Type"
  • Uses a standard chain-link fence & two steel cables
  • Moderately effective, but requires immediate repair
jj types 5

Impact Resistant Barriers

  • A common form of this barrier type are bollards.
  • Can greatly reduce or stop the forces of car or truck impact
  • Typically used to protect a fixed structure from vehicular damage