Sometimes these things meet a lot of resistance before they are implemented.
At the junction of the original I-15 and I-10 in San Bernadino the ramp to LA (coming from Las Vegas) had at least one serious crash a weekend and several fatals a month. This is set in the pre airbag and seat belt law era by the way.
The guard rail end had some sort of renewable barrier for the convenience of the clean up crew but it didn't do much for the crash victims.
The inventor of the sand and water filled compression barrels had been trying unsuccessfully for a year or so to get the state of California to try them somewhere but they refused to pay for anything that sounded that stupid.
After a particularly bad weekend on that ramp, he offered to put a set up for free and even took out an insurance policy to assume liability if it failed. So for free someone said OK.
Upon finishing the installation, the inventor and the dude from the state highway department are walking back to the truck when they are deluged by sand and water falling from the sky!
Guy climbs out of the car that was going at least 70 when he hit the drums and asks "what the hell was that doing in my way?" (That was paraphrased to spare the innocent from profanity) Then his wife and 4 kids climb out of the car - all uninjured other than minor bruises and cuts. At that speed of impact it would have been 6 fatalities an hour earlier.
Funny thing but his barrier became a permanent fixture on that spot that day and he couldn't make enough of them fast enough to keep up with demand..