By on August 24, 2017

blind spot, Image: Ford

Lane departure alerts and blind spot monitoring systems can significantly reduce crashes if consumers use the features, according to two recent studies by the Insurance Institute for Highway Safety. While this information falls into the no-brainer category, rarely do we get specific metrics on these particular technologies.

“This is the first evidence that lane departure warning is working to prevent crashes of passenger vehicles on U.S. roads,” explained Jessica Cicchino, IIHS vice president for research. “Given the large number of fatal crashes that involve unintentional lane departures, technology aimed at preventing them has the potential to save a lot of lives.”

One reason there isn’t a lot of data on the effectiveness of the technologies is because it’s so difficult to quantify accidents that don’t take place.

Mixing up correlation and causation is a pitfall researchers perpetually have to avoid. The evidence of things not seen is inherently troublesome and the IIHS study may suffer from a bit of the old “magic rock” fallacy. If you’re unfamiliar with the concept, The Simpsons tackled it in 1996 when Lisa alleges the town’s expensive Bear Patrol may have nothing to do with why there are no bears.


However, while we should keep this in mind as we examine the stats, it isn’t meant to undercut the inherent usefulness of lane departure or blind-spot alerts. Some warning is always better than no warning at all when you’re absent minded behind the wheel.

Using previous studies and data from police-reported crashes, the IIHS concluded that systems that warn drivers when they’re beginning to drift out of their lane reduce injuries by 21 percent and total collisions by 11 percent. Cicchino believes the technologies could have prevented nearly 85,000 crashes and 55,000 injuries in 2015, had they been installed on all vehicles at the time.

Similarly, IIHS found blind-spot detection systems cut the chances of lane-changing crash injuries by 23 percent and total accidents by 14 percent. However, a 2015 study of lane departure warnings in U.S. truck fleets found the technology cut the rate of relevant crashes nearly in half, and an analysis by Volvo cars in Sweden found a reduction of relevant injury crashes of 53 percent.

While particularly alert drivers probably have a less-than-dire need for such systems, they are useful. A little light that tells you when a car might be just behind your rear fender is indeed a handy item. Likewise, everyone can benefit from lane departure warnings after a few brain-dull hours spent on the expressway.

Research from the Highway Loss Data Institute backs up the IIHS claims, suggesting the injury rate could be lessened by up to 86 percent. However, the IIHS claims the HLDI hasn’t uncovered direct benefits in the form of lower claim rates from lane departure warnings — primarily because lane departure is typically bundled in with other safety systems that could skew the data.

In the most recent IIHS study, Cicchino included vehicles with optional lane departure warning from six manufacturers: General Motors, Honda, Mazda, Mercedes-Benz, Subaru, and Volvo. Automakers provided information about the presence of optional features on specific vehicles (via vehicle identification numbers) and researchers used 2009 through 2015 crash data from states that provided VINs of the cars involved, making it possible to identify the vehicles and determine if they had lane departure warning systems or not.

You can make up your own mind as to how accurate the estimates are. In the meantime, both institutes feel that implementing the safety features on more vehicles would save lives and significantly reduce accident rates. “Most of these kinds of technologies started out being optional equipment on the highest trim level on the most luxury vehicles. It’s starting to filter down more but it still hasn’t filtered down all the way,” Cicchino said.

Cost is the largest factor, according to a the Alliance of Automobile Manufacturers. “While the industry is proud of these innovations, and eager to see customers embrace these advancements, it’s important that consumers be able to decide how best to spend their safety dollars on these technologies,” an AAM spokesperson said in a statement. “Determining which features are right for their families is a decision best left for consumers.”

[Image: Ford Motor Co.]

Get the latest TTAC e-Newsletter!

41 Comments on “Lane Departure Warnings, Blind Spot Alerts (Probably) Reducing Crashes: Study...”

  • avatar

    Cue the naysayer comments about how this is all a waste of money and the safest car is a stripped down Golf without so much as a seat belt.

  • avatar

    I find it interesting that the reduction in injuries is higher than the reduction in actual collisions. How is someone getting injured by driving out of their lane if they don’t get in a collision?

  • avatar

    My car doesn’t have this, but it is a comforting feeling when I am in another’s blind spot and I see that little light on their mirror. Especially given my car’s size (mx5).

    I still try to avoid lingering in that spot for too long. The light may be a subconsicous reminder to move.

  • avatar

    Given the huge blindspot in my Countryman, I wish it had (this is a base model!) some kind of alert.

    Given my old man’s tendency to wander a bit in his lane, the lane departure in his Buick is a godsend.

  • avatar

    I’d like these to blink fast when you’re almost going to hit someone and go on solid when you’re definitely going to.

  • avatar

    Ive been driving 48 years. My personal odometer has rolled over millions of miles. Do I need a tiny light on my side view mirror telling me someone is in my blind spot? Then theres the TV screen that give me a nice view when I’m backing up? Like reversing out of my daughters driveway, with kids on skate boards, and moms pushing strollers . Beeping alarms to inform me I’m about to back into a rusty old Ram truck with a trailer hitch sticking out?

    I can take it farther. Whats with the button that blows cold air up my butt on a hot day ? Another control to keep the same part of anatomy warm when its -25 F ? A warning that informs me “your shutting the engine off when your not in park”

    Do I need all this stuff ? I managed to drive a 62 Pontiac across Canada and back without the benefit of power steering.

    So to answer all my own questions…Damn right ! I need all this stuff. Todays vehicles are infinitely safer, and way more “user friendly ” then even vehicles from a decade ago. If modern technology can help alleviate driver error, and prevent a small child from being run over . Bring it on.

  • avatar
    SCE to AUX

    While I don’t want a fully autonomous vehicle, I do welcome this particular technology.

    I’ve had too many near-misses related to lane departures and blind spots (committed by me), and as I age, these would be helpful driving aids.

    • 0 avatar

      The wife got a new Forester in April with all of the driver aids. The back up camera is nice but I still haven’t gotten to the point where I rely on it, I still keep checking all of mirrors. I expect that she will get better use of it as she backed her last car into something (slowly) twice. The lane departure has only clucked at me when I’m swinging wide around bicyclist or a stopped car without hitting my turn signal, so that’s not doing much for me. I barely even notice the blind spot alerts because I’m still so accustomed to carefully checking my side mirrors when changing lanes (and I’ve got the mirrors properly aligned so that I can actually see into those spots) that I only notice the warning light after I’ve spotted the vehicle that’s there. The only aid that’s impacted my driving is the forward monitor. Both my wife and I have had the Forester begin braking as we closed on someone suddenly slowing down in front of us, and I do appreciate it’s ability to work with cruise control to manage a safe distance while highway driving.

      • 0 avatar

        @ Clutch: I like what you said about having the mirrors adjusted in a manner that let’s you see the “blind spot”. I do that also. For mid-sized cars and larger, someone going around me on either side is always in one of my rear view mirrors. When they hit the blind spot I have their right rear quarter in the inside mirror and the front left quarter in the side mirror – for a left side pass.

        All that said, I think these kind of devices can only help keep us safe – if the driver is paying attention to the warnings.

    • 0 avatar

      Me too. I was merging on the same on ramp Ive used a zillion times. I checked my mirrors and put the left signal on, and just about tagged a full size SUV. My bad ! The little light came on and saved my a$$.

      I always took pride in my defensive driving skills. However, as I age I know I’m not as good as always thought I was. This modern technology does do the job. The near miss was still my fault. I should have double checked my side view.

  • avatar

    It has to be helping, they call it a “blind spot” for a good reason. The problem with lane changes is not the first 2 cars but the 3rd one. Since car #2 swerves to miss car #1 but then collects car #3 because the movement was so sudden.

    I rent cars often as my job involves some travel and blind spot + backup cameras have become a god send when you pick up a strange vehicle at midnight and have to immediately drive to some random hotel.

  • avatar

    I currently drive a 2009 Element (which I love), but my wife drives a Volvo XC60 that has these new safety features and I have to confess that I’m seriously considering trading the Element to get something with similar safety features. I’ve been looking for a while now and I’d say that an Ouback is tops on my list, followed closely by a new CR-V (or perhaps even a 2018 Accord!).

  • avatar

    I really like the blind spot monitoring and back up camera. Blind spot monitoring means I no longer have to turn my head around, eyes not looking as to what is in front of me, to see if anyone is in the blind spot. Very dangerous on the California freeways going the usual 5 mph over the limit. Back up cameras are to be used in conjunction not instead of side mirrors. Too many people make a race out of backing up, it should be done slowly so you don’t kill the fast moving object that does not see you.

  • avatar

    I was skeptical, but having it now on a car I will concede it’s a useful safety technology. I could see it though being like the “3rd” brake light where it just becomes something in the background and people stop noticing it.

    • 0 avatar

      Seeing a third brake lamp still lets you know if indeed the vehicle is braking, or if its an optical illusion created by their tail lamps or your head lamps. We don’t notice it consciously, but I believe it serves as a subconscious confirmation when we see it. It also serves as a backup if the lower lamps are inoperative or blocked from view. Just because you don’t think about it does not mean its function isn’t served.

      I like the CHMSL, so much so that I plan to retrofit vehicles I own in the future without it. (I had purchased a small rectangular LED red lamp and planned to install it in my Mercury Zephyr.) Likewise, I always verify it is working when buying a used car (or make it work), and sometimes I look back when holding the brake because you can usually see its reflection in the glass (to make sure the bulbs aren’t out).

      I do consciously notice them most of the time.

  • avatar
    Steve Jacobs

    I too bought all this stuff on a new car, paying an early penalty for getting out of a lease. The blind spot warning light and, on my BMW, the vibration in the steering wheel really help. Also, the adaptive cruise control.

    My onlyh problem with thses functions is when I rent a car, their lack is disturbing, to say the least. I recently rented a bmw x# that didn’t even have a backup camera. Ridiculous.

  • avatar

    Lane departure sucks on my Honda and I turned it off on day 2. It was nothing but false alarms, which do nothing but desensitize us to the device.

    However, for blind spots: As much as I love to say “Adjust your mirrors correctly and there are no blind spots!” the fact is that a lot of OE mirrors suck…and most drivers just won’t adjust them. When I’m behind most cars, I can see the driver’s face in all three of their mirrors. Hint: That’s not right.

    So I definitely get some small sense of peace when slowly passing a Lexus RX and I see their little amber light come on. It’s just one more measure of proactive safety, and I’m generally in favor of those. The only danger is when someone becomes so dependent on it, they forget the basics (eg, they rent a car without it and crash).

  • avatar

    Blind spot monitoring, if nothing else, provides an additional safety and confirmation to the driver as to what’s to the left and right. It works really well in our Taurus SHO and Yukon Denali. I wouldn’t buy a car without it. It’s a great technology. I don’t think you should solely rely on these safety systems, but you can’t go wrong by having them.

  • avatar

    My next car will probably have blind spot monitoring because it’s so common now.

    However, I’ve found that aspherical mirrors do a great job of showing who’s beside you up to 2 lanes over. It would be great if they were required on cars sold here. Of course most people probably couldn’t handle adjusting them correctly and would be looking at the side of their car.

    I think all of the nanny tech is a good thing, assuming people use their mirrors and common sense. Those seem to be tall orders these days though.

    • 0 avatar

      Absolutely right. I spent five days driving a Lincoln MKZ (a Fusion in fancier paint). It had huge blind spots – the B pillars are more like I beams. If you turn your head to look back, all you see are headrests, B pillars and C pillars. I wouldn’t take one of those if you gave it to me for free.
      What cars REALLY need are larger side view mirrors, larger side windows and larger rear windows. The electronic nannies are there to compensate for the ever tinier glass bits. When their Chinese-built capacitors fry, the cars will be undrivable.
      On another point, windshields shouldn’t have more than a 50 degree rake. The hell with that last .001 of drag coefficient. They get too reflective at near-flat angles and also let in a lot more solar heat. Automakers can straighten up the windshield a bit, and put that extra glass where it belongs, on the other windows.

  • avatar

    They are good systems, but can manufacturers use frequencies that don’t set off radar detectors? Chrysler’s system appears to be the worst, always setting off my Ka band warning

  • avatar

    The way I’ve setup the mirrors in our van, I can see a vehicle in my rear view mirror and as it disappears from there, it appears in my side mirror. I still check my blind spots before making a move of course. So far I’m very confident in my abilities and mirror setup to not need BSM. But, it only takes one mistake… so I guess it could be useful!

  • avatar

    I recently attempted to merge in front of a black car, with it’s lights off, at night-time driving in my blind spot on an unlit section of highway. Needless to say this tech prevented the inevitable.

    Totally justifiable, but it won’t prevent accidents due to human complacency. Those people who weren’t looking over their shoulder will probably not think to check the icon in their mirror or pay attention to the beeps.

  • avatar

    I find it easier to just turn my head like a competent driver rather than relying on technology.

    All this does id encourage poor driving habits.

    • 0 avatar

      I invite you to try that with my 350Z. The blind spot is HUGE due the angle of rear window, micro-sized side windows and large support pillars for the hatch blocking your view. And yes my mirrors are adjusted properly. Pretty much any low, sleek 2 door coupe (like a ‘Vette or Mustang) has the same problem. My Dodge Dakota Quad Cab is the opposite, it has 4 big side windows and a large, upright rear window. Thus no problem seeing everything around it. I would assume given the greenhouse of a Ford Flex it too has great visibility.

  • avatar

    My wife’s car has lane departure warning but no blind spot monitoring, while my car has blind spot monitoring but no lane departure warning. I wish my wife’s car had BLIS because when I shoulder check to the right, the contours of the rear 3/4 window make it look like a car is there! The LDW is cool because it vibrates the wheel when I clip apexes, as if I am running over the rumble strips at the track. All in all I am sold on these systems as they work effectively and inobtrusively. However the one feature that is absolute money is on my car…rear cross-traffic alert. That has saved my ass a few times.

  • avatar

    I never knew I needed blind spot until it save my tail a few times in my Challenger.

    • 0 avatar

      Extra-large Blind Spots are included as no-extra-charge standard equipment.

      • 0 avatar

        LOL,I like to refer to it as riding in a coffin with slits for windows ;)

        • 0 avatar

          The Challenger is still much better than the Camaro in that regard.

          The Camaro I test drove had blind spot monitors, and they were absolutely necessary. Unfortunately they were tied to a very specific and expensive package that was only available on the top trim of the car. You’re taking your life in your hands if you can’t afford leather seats.

  • avatar

    Truth be told I preferred the smaller secondary spot mirrors I had in my previous lease than the Blind spot monitor I have now.

  • avatar

    See, you can fix stupid, some of the time!

  • avatar

    Well, this is only anecdotal but my car lacks these features while my wife’s car has them. I drive my wife’s car fairly often but since I’m so used to looking over my shoulder to check the blind spot, I don’t even notice the light in her mirrors. So far I haven’t had any situations where it would have helped. So maybe blind spot warnings are useful if you’re an inattentive or inexperienced driver. For those of us who have been driving (safely) for decades without them, they don’t seem to be of much benefit.

    The lane departure warning is similarly useless to me since I’m extremely vigilant about staying in my lane and the only times it goes off is when I am purposefully straying, for example, to dodge a truck or bus drifting into my lane. Or when the lane markings are worn away or end.

    Autonomous braking is far more useful since there are times where vehicles in front of you may stop suddenly while you’re checking your mirrors or someone cuts in front of you suddenly or whatever. Even an experienced driver can be caught by that. So that is a feature I definitely want.

  • avatar

    I’m OK with blind spot warnings. I just wish we could go back to having smaller blind spots…

  • avatar

    We made Mom go the full Monty on her new Lincoln and checked every box for these new fangled safety items. We set them on maximum safety settings and so far so good. Sure she has run over a few curbs and brushed a pole in a parking lot but nothing major – yet…

  • avatar

    How much does this feature normally cost? I have provided the service a few times this year free of charge, by laying on my horn when some idiot starts merging into my lane as I’m passing him. I should send them an invoice.

  • avatar

    Surprising to me how many people on this site appear not to set their mirrors properly so as not to have blind spots. I would expect that from the general population but not on an automobile enthusiast website.

    On probably 9 out of 10 vehicles (I concede there are exceptions – most of which I would imagine are vehicles with narrow fields of vision out the rear window), if you set your mirrors correctly, there is no blindspot and no need to shoulder check (which is an inherently dangerous activity), and whenever you look over and see that blind spot monitoring light on in the mirror, you’ll also be looking at the thing supposedly in your “blind spot.”

    • 0 avatar

      You might be surprised how many vehicles can have blind spots regardless of what you do with the mirrors.

      My ’03 330i had a left-side blind spot even with the mirror adjusted as far out as it would go. The mirror was too damn small.

      The problem was caused by North American requirements for “unity magnification” (1:1 reflection with a flat mirror) for the driver side mirror. I replaced it with the euro-market aspherical mirror, dramatically increasing the field of view.

      The unity magnification requirement is ridiculous to me. I don’t see how having to realize an object in the mirror is closer than it appears is more dangerous than not seeing the object at all.

      Although it’s likely true that most drivers don’t know how to adjust their mirrors correctly, they aren’t guaranteed great results even if they do know.

Read all comments

Back to TopLeave a Reply

You must be logged in to post a comment.

Recent Comments

  • la834: I don’t get why 2400w heat guns (or toasters, or dishwashers, etc.) aren’t readily available in...
  • 28-Cars-Later: I’m not sure what you mean, the 260 is unrelated to Our Lord of Eternal Torque.
  • Lightspeed: Eleven years ago I bought a then 10-year old Lexus. For giggles when I was shopping, I looked at a couple...
  • theflyersfan: @redapple – in 13 months, 14 service visits. Most were multiple days, and one wiper repair was...
  • Carlson Fan: “The 260 may have been a little better than the granddaddy to the Most Blessed 3800 IF it was...

New Car Research

Get a Free Dealer Quote

Who We Are

  • Adam Tonge
  • Bozi Tatarevic
  • Corey Lewis
  • Jo Borras
  • Mark Baruth
  • Ronnie Schreiber