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Guardrails: Only for people in cars

Quick quiz: According to the Maryland State Highway Administration, what is the purpose of guard rails on roads?

People are not roadside obstacles. Photo by Complete Streets on Flickr.

(1) to protect everybody
(2) to protect people in cars

The correct answer is (2).

I found this out recently when I asked the SHA for a guard rail after two people drove their cars into our side yard. The yard is on the top, flat side of a T intersection with a 3-way stop. The house has been there since 1911; the T intersection, since 1926.

One April night in 2010, a driver on the stem of the intersection drove past the stop sign and right on into our yard, banging into a pine tree and running over one of the two apple trees, until his car stopped with its headlights shining into a bedroom window. Luckily, nobody, including my family, was injured.

I figured that this incident was a fluke.

Almost exactly one year later, another driver on the stem of the intersection drove past the stop sign and right on into our yard, running over a pine tree and the second apple tree. Again, luckily, nobody was hurt, or so we assume, given that the driver was somehow able to back out of the yard and drive away before we got home.

With no more apple trees left, I was worried that the next car would hit a family member. So I asked for a guardrail.

After a thorough and professional site visit by a SHA engineer, I received an email from Cedric Ward, Assistant District Engineer - Traffic (Montgomery County) at SHA, which said,

According to [SHA's] guidelines, a roadside barrier is warranted for only the most severe roadside obstacles.... Considering that none of the[se]...roadside obstacles are present at the subject location, a traffic barrier is not warranted at this location.
Looking at the 2006 Guidelines for Traffic Barrier Placement and End Treatment Design Ward referred me to, I learned that "the function of a roadside barrier is to shield the motorist from impacting an obstacle along the roadside."

According to the SHA guidelines, a traffic barrier is warranted only if there is a roadside obstacle that cannot be removed or relocated out of the road's clear zone, defined as "the total roadside area, starting at the edge of the travel lane, available for safe use by errant vehicles."

Thus, the guidelines allow SHA to put up a traffic barrier to protect people in cars from driving into embankments, bridge parapets, non-breakaway signs or lights, signal supports, water bodies more than two feet deep, large boulders, utility poles, drainage ditches, and/or trees.

But they do not allow SHA, in general, to put up a traffic barrier to protect people who are not in cars from being driven into. People who are not in cars are not a roadside obstacle that motorists need shielding from. And indeed, at least judging from our experience, it is not dangerous for a person in a car to drive into a yard where people, not in cars, might be.

To be fair, the guidelines concede that, on urban streets, a traffic barrier may be placed "in sensitive areas such as school playgrounds." So perhaps we might have qualified for a guard rail if the driver were likely to drive into our house, instead of just our yard.

As yet, the lack of a guard rail has not really been a big problem for us. Nobody was hurt, apple trees can be replaced, and we have installed some new, large landscaping on our property. And the SHA did put up a yellow sign with a black two-directional arrow at the intersection.

But the lack of a guard rail was a very big problem for Kelay Smith and Derrick R. "Mooky" Jones, who were killed by a driver in Prince George's County in August 2008 while they were walking along a stretch of MD Route 4 without sidewalks or guard rails.

And it should be a very big problem for the State of Maryland, which was ordered by a civil jury in March to pay $3.3 million to Smith's daughter and mother.

State traffic barrier guidelines notwithstanding, people in cars are not the only users of the road. What will it take to get the SHA to revise its guidelines to routinely take the safety of all road users into account? This is not a rhetorical question.

Miriam Schoenbaum lives in upcounty Montgomery County. She is a member of the Boyds Civic Association, the Boyds Historical Society, and the Action Committee for Transit


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The solution along country roads (at least where I grew up) was to place rather large( 3' + boulders), decorative boulders mounted (cement/rebar) on a hidden foundation. It looked nice and would stop anything short of a fully loaded semi. At that point it's up to SHA to determine if the 'driver' needs to be protected from your rock

by m on Aug 15, 2011 3:42 pm • linkreport

Keep in mind that guardrail is generally intended for parallel use; that is, along the roadway. In situations where the guardrail is struck perpendicularly: more flexible barrier may negate their intent entirely or may fail & more rigid barriers are quite likely to kill or seriously injure the vehicle occupants. So essentially: the risk of people being in the yard must be compared to the risk of people being killed/injured by striking the barrier itself... an easy decision when you're the one in the yard; but an exceedingly difficult decision when one is obligated to act on behalf of the greater public.

In situations as you described, guardrail would only be a band-aid solution that doesn't look at the actual problem. That is, it seems people do not realise that there is a stop sign & intersection. Without knowing further details, I actually believe that the arrow warning sign was an appropriate first step, though that's not to say there may be other options which could be feasible to bring greater awareness to the intersection & better-control approaching speeds/handling.

by Bossi on Aug 15, 2011 3:57 pm • linkreport

Jersey barriers! Just kidding...

by MrTinDC on Aug 15, 2011 4:01 pm • linkreport

I don't really think guardrails are the best solution in most cases to cars running off the road and causing property damage, injuries, and death. The bottom line is we can't put guardrails everywhere, they don't protect pedestrians unless there's a sidewalk behind them*, and they do create a hazard to drivers if hit at high velocity.

I think a better strategy is to slow traffic appropriately given surrounding conditions (like houses, pedestrians, and stop signs) with visual cues, speed limit reductions, road diets, etc. And obviously, we need a lot more sidewalks to provide safe places to walk. In this light, I'd agree with Bossi that the yellow sign is an appropriate measure to call attention to the intersection and get drivers to slow down before they hit people, your apple trees, or a guardrail.

(*If there's no sidewalk behind a guardrail, then people are likely to walk on a shoulder on the traffic side of the rail, and are thus not protected.)

by RichardatCourthouse on Aug 15, 2011 4:11 pm • linkreport

Step 1: order a whole bunch of cinder blocks to be delivered from Home Depot.

Step 2: build a large obstacle right on the edge of your property. One that has a functional purpose of some kind, and that will do some mischief to the next errant car.

Step 3: call DOT and ask for a guardrail.

by Omri on Aug 15, 2011 4:29 pm • linkreport

Perhaps a 1/2 ton boulder incorporated into your landscaping would do the trick. Check your utility service to make sure you won't block future generations from digging up a service line, and plop that sucker down.

by Will on Aug 15, 2011 4:31 pm • linkreport

big rocks have been the solution around where I grew up. 2-3' rocks placed along the shoulder seem to be the usual solution people have implemented. I'm not sure if they were anchored like the previous person mentioned. if the speed of cars on the stem portion of the roadway was high (40-50mph?) I'd probably lean towards larger 3-4' stones staggered along the border. if they're going fast enough, they may still go over them, but it'll do enough damage to the vehicle that it'll likely slow down and if not the engine will likely be damaged so it can't continue to go into your yard past whatever distance momentum would take it. the usual usage I have seen is 2' rocks spaced such that people can't drive/park past the shoulder in their yards, seems effective.

by John on Aug 15, 2011 4:32 pm • linkreport

The problem with mandating a DOT to place guard rails to protect people is that there is no end to it, and people would massively protest DOTs placing guard rails all over their front yards. There would also be incredibly complex liability issues.

How happy would you be if SHA put a jersey barrier in front of your garden?

by Jasper on Aug 15, 2011 4:42 pm • linkreport

I thought the only purpose of the guardrail was for the convenience of the ambulance driver and wrecker crew. It is such an inconvenience to enter someone's front yard (or their home) to retrive the body of the car or of the driver!

by Adrian Hunnings on Aug 15, 2011 5:59 pm • linkreport

Recently on a trip back to Tokyo, it struck me how almost every street with sidewalks also have guardrails. They're so ubiquitous that I had never noticed them in the years I lived there. It definitely does make walking feel safer. The flip side is that it makes jaywalking more difficult, for better or for worse.


by dand on Aug 15, 2011 6:02 pm • linkreport


Other points aside, that link just shows railings; not guardrail. They'd immediately fail if struck by a vehicle. Those are specifically intended to prohibit jaywalking (as per the signs along the curbside as well as some familiarity with the area from days of old).

by Bossi on Aug 15, 2011 6:07 pm • linkreport

You're lucky the SHA didn't make you remove your trees because they were hazards to vehicles!

A friend used to live in Mt. Pleasant somewhere, and front steps of the house (nice house, historic SFH, etc.) got hit many times because of a weird street geometry, and a propensity for DUI folks to hit it on Saturday nights. After thousands of dollars in repairs and several incidences, I suggested he buy an operable circa 1975 Oldsmobile Delta 88 and just park it on the street, thus guarding the steps. It would have been more economical.

by spookiness on Aug 15, 2011 6:17 pm • linkreport

I wonder if the answer there is to narrow the T-intersection. They did this on sections of Dale Drive in Silver Spring (cross-streets, not T-intersections though). They even threw in a couple of pedestrian accouterments to boot. For my money, this is the most effective way to slow arterial traffic in residential areas.

The new intersections do not show up on Street view, unfortunately. But here's a link to the overhead:,-77.021072&spn=0.000693,0.001491&t=h&z=20&vpsrc=6

by Dave Murphy on Aug 15, 2011 6:57 pm • linkreport

Only regarding "cars" that are automobiles:

by Douglas Willinger on Aug 15, 2011 10:47 pm • linkreport

Yes, I know - that's one reason why I don't drive an SUV any more. They don't even have a standardized test for roof structure integrity.

by Gamefly on Aug 16, 2011 1:57 am • linkreport

It sounds like you are in need of the standard metro Washington solution: bollards

by ksu499 on Aug 16, 2011 8:18 am • linkreport

makes sense. but does every article have to add to the already pedestrian-centric/anti-car nature of this blog

by JessMan on Aug 16, 2011 8:42 am • linkreport

As mentioned, guardrail is not designed to stop cars hitting it head on and would not be appropriate here. You might ask SHA to consider the following:

-Curb and gutter
-Street trees
-new or refreshed pavement markings, particularly a stop bar
-check that the reflectivity and size of the stop sign meet the federal requirements (an upcoming federal requirement anyway)
-check the placement of the stop sign

The sign they installed should help as well.

Walling off sidewalks from travel lanes with guardrails is not the way to solve traffic or pedestrian problems, especially on neighborhood streets. People make mistakes, crashes happen, and no amount of engineering or enforcement can prevent that. People drive drunk or tired or distracted, and manage to drive over guardrails in that state. Guardrails can create other problems as well, which is why they should only be installed in accordance with the guidelines and the engineer's professional judgment.

by PB on Aug 16, 2011 12:18 pm • linkreport

Sounds like a traffic circle or a roundabout might be called for. Definitely some sort of traffic calming device.

by Robo-SFO on Aug 16, 2011 2:48 pm • linkreport

JessMan: I prefer to consider it pro-people, irrespective of how they are getting around. The reason this blog seems anti-car is that current policies (like the one in the story) are so ridiculously pro-car and anti-people that it comes across as "anti-car."

I mean, seriously, who would have thought that a rail is only approved to protect cars and not people, houses, etc? The homeowner in the story wasn't even a pedestrian, just living in a house.

by SJE on Aug 17, 2011 10:54 pm • linkreport

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