I used to think driving getting more and more dangerous and one reason is the media loves to
sensationalize car accidents Multi-car pileup in North Texas has killed
at least six people Incredible! And with those kinds of stories I was surprised by how the fatality rate has steeply dropped over the decades even with more drivers today on our roads
today We save more lives because of better seat
belts enforcement and catching intoxicated drivers Cars are also safer with crumple zones, Airbags and ABS brakes But did you know we've greatly improved the design and engineering of road barriers in the last 60 years? Like this connection between a guardrail and
concrete barrier In the past vehicles used to be crushed but now they gracefully bounce off and I’ll tell you why later We also removed these terminals from highways which in the 60s made you look like a hot dog and replaced them with something far safer My name is Andrew and let's uncover how good road barriers have gotten to save more lives Roadside safety equipment is made by different companies and their products undergo real-life crash
tests to prove their products work In the United States that standard has gotten more rigorous over time and the latest is MASH or the Manual for Assessing Safety hardware Compared to the older 1998 standard MASH uses heavier vehicles faster speeds and higher angles. MASH-rated equipment has to be built better to handle the much higher impact forces Europe uses a different standard, EN 1317 but the safety principles are similar In this video I'll be focusing on MASH and how it's made our roads safer MASH-rated products have six safety ratings the lowest is TL1 with higher ratings requiring products to stop heavier vehicles at faster speeds The highest TL6 barriers that can stop tanker
trucks are massive structures and rarely used on
our roads today For each level, all equipment has to pass three tests Number 1 It must keep the vehicle upright
with no rollovers which can cause severe injury to occupants which means this product would fail and would need a redesign Number 2 The vehicle can't tip more than 75 degrees or go over the barrier that means this barrier does not pass MASH testing Number 3 There can be no penetration or crushing of the passenger compartment and impact forces must be below the maximum allowed All of this data is recorded and analyzed to figure out if a product fails or passes MASH-rated equipment has been mandated for new installations like this concrete barrier and is an important part of the safety system Barriers prevent vehicles from driving into hazards like buildings bodies of water and oncoming traffic But, crash barriers are themselves a danger they're longer, closer, and easier to hit which increases the number of crashes even though severe injuries and deaths
are greatly reduced It's far better to have vehicles run off the
road into a safe area of land called the clear
zone which allows drivers to recover or reduce
the severity of a crash Engineers can create clear zones by removing hazards and grading the land according to guidelines which covers things like the steepness and
the width required But it might not make financial sense or it's not possible to create a large enough clear zone which is when barriers can be used These barriers come in three categories concrete, guardrail, and cable You'll often see concrete walls like this
one While it seems simple there's some surprisingly well-thought-out
engineering If you look at their profile many aren't vertical but sculpted to reduce crash forces When hit your vehicle rides up the sloped surface and this vertical motion dissipates energy which reduces vehicle damage and impact on occupants Unfortunately this lifting motion can cause the vehicle to roll over under high speeds and impact angles To improve this engineers tested many shapes and while the New Jersey barrier is popular, Single Sloped and F-Shape are better as they don't lift the vehicle as high which increases stability and prevents rollovers In comparison vertical barriers minimize upwards movement. They're often used on bridges as you don't want vehicles to be catapulted
over the sides Unfortunately that increases the impact forces and wheel
damage which could cause the vehicle to veer sharply
into traffic As well higher lateral forces can push your head through the window which can cause head slap and greatly increase your chance of dying For those reasons you'll mainly see sloped barriers on highways today Concrete walls are often used where you can't
have any movement for example if it's close to a hazard When there's more space you'll often see a semi-rigid system instead These can use a box-beam or more commonly you'll see a flat corrugated guardrail connected to a wooden or metal beam for support These are driven into the ground and often use a strong post system which is
quite ingenious When hit the posts rotate outwards and down transferring kinetic energy through the soil which reduces impact forces As well the rail detaches so it stays at the right height and in contact with the vehicle which also helps prevent tearing On older designs the rail more likely to remain connected and can rip letting the vehicle through This tearing can also happen if the posts can't easily rotate which pulls down the rail The new safer MASH-rated guardrail only used a minor height increase and connection change versus the older rail to better contain heavier vehicles and prevent taller ones from jumping over
the guardrail It's also likely there's an offset block that keeps your wheel from snagging This helps the guardrail improve stability and reduce sudden impact forces on occupants Remember this guardrail and concrete
connection I mentioned earlier? Engineers figured out they need to add extra posts to prevent vehicles from behind crushed If the connection between the two is not reinforced the guardrail bends and tears with the vehicle smashing into the concrete
face with horrific outcomes Engineers added posts to stiffen the connection and allow the vehicle to bounce off as it
was designed Finally we have Cable Barriers that are placed in medians to prevent vehicles from flying across and
striking oncoming traffic These have existed for decades as you can see in this 1930s Missouri Transportation video Modern systems use three or four cables to
safely catch vehicles and are under high tension to withstand multiple impacts and reduce movement Unlike concrete or guardrail there's some controversy with cable barriers. Critics say they're dangerous and only put in because of the low price Transportation engineers argue they reduce
serious injuries and can save more lives Let's look deeper Cable barriers are several times cheaper than concrete and 40% cheaper than guardrails because it uses fewer materials and lighter machinery which reduces logistics, construction, and
product costs You can also install cable barriers on slopes which saves money on landscaping In comparison concrete barriers can require heavy machinery,
a sewage system, flat ground, troublesome logistics, and more time The big downside with cable barriers is the
greater vehicle penetration as it's easier to slip between the ropes This is shown in two studies evaluating over
10000 crashes which compared concrete, guardrail, and cable systems From this people say cable barriers are unsafe and cause way more deaths But that's not completely accurate In fact, these two large studies showed an equal or slightly higher fatality rate versus concrete As well what isn't mentioned enough is that cable barriers can reduce injuries. Cable barriers stretch when hit which decreases injuries due to reduced impact forces Both studies found a big reduction in total injuries As well this stretching helps prevent the
vehicle from bouncing back into traffic and causing a second, more dangerous accident More importantly the lower price lets you build more cable barriers versus other types and the added length saves more lives That's important as we don't live in a world
with unlimited money and there are many construction projects and many miles of unprotected roadways I could keep going but this isn't a video about cable barriers
versus the world Instead, I wanted to show that each barrier
has its benefits and drawbacks To pick the right system engineers weigh factors like traffic, volume, vehicle types, and landscape So besides the barrier itself at both ends you'll often find a protective terminal like this one that saves drivers if they run into it In the 60s, the state-of-the-art was fishtail
or spoon designs that tried to distribute the impact across
more of the vehicle These were widely used decades ago and were
awful Unfortunately this act as a spear when struck head-on and can result in catastrophic injuries In the late 60s turn-down ends were used which bent the rail 45 degrees and buried it in the ground These prevented spearing but vehicles could easily vault or roll over which caused serious injuries or fatalities In the early 70s various breakaway cable terminals
like this one here were invented to minimize spearing It works by having the end roll away with posts breaking off to redirect vehicles
into a clear zone These were used for twenty years but phased out as they were too stiff for small vehicles and could still spear occupants In this test footage the guardrail smashes into the side of the vehicle and would dice up any occupants inside Nowadays we have energy-absorbing terminals that let people walk away from highway speed
crashes. For example, this is the MSKT MASH Sequential Kinking Terminal System and costs around $3000 US Dollars All terminals including this one have to do two things protect occupants that hit it head-on and anchor the guardrail The MSKT when hit head-on dissipates kinetic energy by crushing and kinking the rail while shooting it out the side Its post and anchor are designed to breakaway safely as the head travels down the guardrail and slows and controls the vehicle What I found impressive is the terminal has to do the exact opposite and provide tension when the rail is hit The cable and ground strut keeps the posts and rail from being pulled down which is called anchoring Otherwise the guardrail releases from the end post and the vehicle runs into the hazard Also if hit where the rail isn't strong enough to redirect vehicles the MSKT safely lets vehicle through which is known as gating That's not a problem as engineers add a clear zone behind it While there are other terminals I'm going to talk one more because it's cool This is the Trinity Softstop. When struck head-on it crushes the guardrail vertically pulls it through the impact head and shoots it under the vehicle You can see how the guardrail slides through
the impact head as seen in this assembly video and what the rail looks like after its been crushed Not only does this keep the guardrail off the road improving safety but it keeps the rail anchored and maintains
tension in the system While the terminals for guardrails were fairly compact I discovered these larger units are different They're called crash cushions and are placed in front of fixed structures such as bridges toll booths, and concrete barriers Before crash cushions were created in the 80s engineers used ramped ends which produced dramatic and dangerous results Nowadays we use crash cushions in these three categories to safely stop vehicles Starting with sacrificial systems like sand barrels these slow vehicles down through the transfer of momentum They're arranged by weight from lightest to heaviest so small vehicles can be gently slowed down and still protect heavier ones These systems are cheap around $3000 for the parts but anything hit needs to be replaced and it's messy to clean up These are also useful for construction sites with one model using a metal sled that
controls the vehicle as it crashes through the water-filled cartridges There's also a mobile version that is mounted
to the back of trucks that are used to protect road crews Next, we have cushions like this QuadGuard
M10 that are better for frequently hit locations When hit the steel structure collapses but
is designed to survive and can often be reused by pulling it out
with a truck Afterwards you'll have to replace the cartridges inside which can cost around $900 each Larger systems can use six of these which can get expensive if hit often For spots with many collisions engineers use cushions that bounce back or be easily reset when hit and requires less time and money to repair There are many designs but I found SCI's Smart Cushion particularly interesting What's neat is the gas cylinder inside adjusts the stopping force based on weight
and speed so cars and trucks have the right resistance After an impact the smart cushion can be quickly reset by pulling it out and replacing a few bolts Other systems like Traffix's Compressor use high-density polyurethane to absorb and
bounce back after an impact While restorable cushions can be double or triple the price of units that use replaceable cartridges the repair costs are much lower and with enough crashes restorable units save money in the long term This is just one example of how engineers
can maximize protection and justify how your money is spent That brings us to how governments figure out how much money is worth spending to save your life or prevent a serious injury Those values are called crash costs and are used to determine if safety improvement projects are economically justified Engineers compare costs like adding a barrier to the benefits like saving your life to figure out what safety measures should be added Governments value your life and limbs differently depending on your location but the average to save your life in 33 states is 4 million dollars If you want to learn more about how these values were calculated and used I'd recommend you google the podcast "Lives vs The Economy" by NPR's Planet Money if you're interested While it's nice that the government is thrifty
at spending your money imagine being told saving your life isn't
cost-effective That's what happened in my province of Ontario on a stretch of Highway called "Carnage Alley" which had no median barriers After a series of deaths from vehicles crossing the median and hitting oncoming traffic local groups like "Build the Barrier" were created and they lobbied to have the road upgraded
with a concrete wall The Ministry of Transportation MTO disagreed and as you can imagine people were not happy The MTO claimed it wasn't worthwhile to make
carnage alley safer because of a lack of traffic on that stretch
of the 401 The government's position speaker is appalling Well with public pressure a cable barrier was installed and later the government committed to concrete
barriers along the entire stretch What I learned is that that road safety can
be about public perception as it is with engineers trying to protect
as many people as possible But, I hope with this video you can appreciate our roads, engineers and even the government a little more As to the future of this channel while I focused on dashcam reviews I want to do more videos like this one and reveal the hidden world of how businesses and governments pick and use products Like, subscribe and if you want to support
more of this content consider donating, there’s a link in the
description Would love to hear your comments and thanks for watching
