A cost effective solution to K-4/K-8 barriers on road ways up to 20 feet wide are
barrier arms. With proper design, you get full open or close in 6-7 seconds.One type
has steel below grade (where the concrete has been poured) and the other type is
with the concrete on the surface.The above grade option offers less installation
costs and with the use of the cement blocks, you can get a higher K rating. However,
it will require a longer travel distance, as the concrete is designed to move a few
feet with animpact. These do not provide any type of pedestrian control.