Explain guard rails in California to me
June 16, 2021 8:51 PM   Subscribe

I get there there are few, but why are there any at all?

Overly the years I've traveled Route 1 and other incredibly windy and narrow roads in Northern California that abut cliffs with terrifying drops. Periodically you see a guard rail. Sometimes the guard rail is alongside a giant cliff, but just as likely it is next to a small gully or sometimes just a field. Usually there is no guard rail at all.

I don't understand what determines whether to put a guard rail in - is it a 90 degree drop? A neighbor complaining? A response to someone flying off the cliff?

I'm less interested in why there are no guard rails, and more interested in why the ones that are put in are there, since there are so few and seem(?) to be strategically placed.
posted by Toddles to Travel & Transportation around California (5 answers total) 3 users marked this as a favorite
Best answer: California's Division of Traffic Operations has a document that provides an overview of the criteria at Traffic Safety Systems Guidance (see section 3.3 for a broad list of criteria and section 3.4 for guardrails at slopes). In particular, the general strategy is "Installing guardrail to shield embankment slopes is largely a result of analyzing the above criteria on a case by case basis and determining whether a vehicle hitting guardrail is more severe than going over an embankment slope."

Also of interest might be Guidelines for Installation of Guardrail from the publication from the National Academies' Transportation Research Board.
posted by RichardP at 9:07 PM on June 16, 2021 [4 favorites]

Best answer: As RichardP says, hitting a guardrail can kill you too, so if there's a way to mitigate the hazard without installing one, highway engineers generally try to do that. The biggest factor is how close the road is to the hazard (i.e. the slope) -- the more space there is, the easier it is for the driver to correct before going over. Additional factors include the traffic level of the road, the curvature and gradient, and the road's design speed. Appendix A of this document provides some tables that determine when guardrails are warranted based on these factors.
posted by goingonit at 9:11 PM on June 16, 2021 [2 favorites]

Here in New York, a lot of the time it’s like this: local people think there ought to be a guard rail in Location X, so they appeal to/put pressure on the relevant government departments/agencies to get one.

About 120 seconds after my Dad took the training wheels off my first bike, I was immediately chased by a large, snarling dog through an older wooden guard rail, drove off what was in retrospect a fairly smallish cliff (It couldn’t possibly have been more than twenty-odd feet high), and landed in somebody’s rowboat that had been pulled up onto the beach. No real injuries except lots of bruises around the bicycle seat area.

Years later, I hit a patch of black ice coming around a blind curve in my elderly Plymouth Sundance (The Ladybug), skidded along the (metal) guardrail until I reached the gap between it and the concrete railing of a bridge, became a bit airborne, and landed with the front of the car a bit smushed into the concrete culvert in the freezing creek under the bridge. Broke 11 bones (possibly 12 but they never confirmed the nose) but managed to crawl out of and over the car, through the water, up the bank and through the snow to the nearest house. Without the guard rail, I most likely would have gone off the road back where the creek was shallower and had frozen mud for banks. (Bonus! The wrecker man found my glasses in the creek bed! He also asked me out, but by the time I could walk and use my hands again he had moved on. He did help me find a replacement used car, The Green Hornet.)

I guess the moral of the story is, guard rails can be a mixed blessing. And I’m not 100% convinced that there is any degree of statewide consistency in the reason for their erection and placement. Americans! We can be pretty parochial when we want to be.
posted by The Underpants Monster at 10:08 PM on June 16, 2021 [11 favorites]

I used to think that guardrails were put in place to protect you from some hazard. I now think they are put in place to protect others from you doing something, either intentionally or unintentionally, bad.
posted by AugustWest at 10:15 PM on June 16, 2021

I can tell you about the strategic placement working, in case it helps.

When I was like 18 or 19 and still rode in motor vehicles, I had a friend that was really into racing cars at high speeds. I think she since may have learned how to race them professionally, but we're no longer in touch.

One night, we went for a drive. She liked driving, and I liked her company. She coaxed some random stranger into a high-speed race up a hilly mountainside. She won. The race ended, we moved on with our lives. Then she was flying down that same hilly mountainside and we ran into a guard rail instead of off a cliff. She told me that if anyone asked, I was to say a deer ran out in front of us. There was no deer. That guard rail totaled her car, and saved our lives.

The more direct answer may be located somewhere in the CA MUTCD.
posted by aniola at 9:39 AM on June 17, 2021

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