Tailgating Doesn’t Apply to ME Because I’m a Good Driver!

Many drivers tailgate in an extreme way and the vast majority of them believe that they are a “good driver” and they have got “good reactions” so they can handle it if things go wrong, but sadly this is simply not true.  This article is the “here’s why!

Heavy traffic on I-90 at Chicago.
Some serious tailgating in the right hand lane of I-90 at Chicago. It only needs two vehicles to bump and the traffic tailback that can result while the driving lanes are cleared, especially if someone is hurt, will delay thousands of people for a significant time. (Copyright image, 2012.)

Around the developed world, crashes due to tailgating comprise a significant proportion of all collisions.  For example, according to Highways England, one in eight of all crashes involve at least one vehicle running into the back of another, and this figure is likely to be similar in all developed nations.

The Reaction Time Myth

The first problem with published “average reaction times” was that up until very recently they were wrong — typically by a factor of two.

For example, in Britain — one of the world’s top two road safety countries over a period of decades — the estimated reaction time for all drivers is still embarrassingly being published as two-thirds of a second, and yet this 0.67 seconds idea has long since been shown to be only around half of the true figure, which is now typically said to be between 1.33 and 1.5 seconds.  One crucial necessity in establishing the recent, more accurate figures was that testing had to take place in a manner which didn’t pre-warn the people concerned that they were going to have their reactions tested.  The alternative gets them ready for the test and quite clearly invalidates the result.

Photograph of Eddie Wren in the WSO's seat of an RAF Hawk Jet, prior to a ten-plane full military exercise over northern England and central Scotland; 2003.
The writer of this article, Eddie Wren, in the Weapons Systems Operator’s seat of an RAF Hawk Jet, prior to a ten-plane full combat exercise — a display of the pilot’s “vehicle” control and concentration second to none. (Copyright image, 2003.)

Some people will point out that racing drivers and fighter pilots have vastly better reaction times than the 1.33 seconds mentioned above and this is entirely true, but that is because it is an essential element of their work.  It is also highly relevant to the fact that people in both of these categories are tired after relatively short races or flights, primarily because concentrating solidly, at that level, undeniably is hard work.

Away from the racetrack, however, it has been shown that racing drivers not only get more speeding tickets than regular drivers but also, crucially, that they have more crashes.[Source: IIHS]   At the very least, this indicates a big change of attitude between their race driving and their public road driving.

Even the squadron of pilots with whom I had the immense and intense privilege of doing what American people would refer to as a “Top Gun” flight — see the above photograph — readily admitted that the biggest cause of injuries they suffered while on the ground came from car crashes.  But how can that be?  How can men and women who regularly do extensive low-flying exercises just 250 feet above the ground while travelling at approximately 800 feet per second then go and get into a car and have a crash, somewhere between 30 and 70mph?  How does that make sense?

It’s because we don’t concentrate properly in a car. We know that’s what it is,”  I was told.

And interestingly I have had exactly the same “confession” when I have had conversations with various airline pilots, too, and a critical problem when drivers don’t concentrate enough is that reaction times get significantly longer than those of which a very alert, well-trained person is capable.  And this is why driving too close to the vehicle ahead can be very dangerous.

So — and here is a key point — if even fighter pilots and airline pilots don’t concentrate enough to stay safe when driving on public roads, what chance do we mere mortals have?

Interestingly, there is an answer.

Photograph of one pick-up truck following another at what might seem like a sensible distance, but because of a very wet road and heavy spray, the situation amounts to tailgating (meaning an indequate fiollowing distance).
Many drivers don’t even recognize this sort of situation as tailgating but for two combined reasons it is.  In addition, it is never safe to say “the vehicle ahead has to brake to a stop so I can brake at the same time,” because under some circumstances the vehicle ahead of you may collide with a static object such as a previous crash, a load that has fallen from a truck, or a broken down vehicle in the traffic lane, and so come to a violently sudden stop.  The driver of the following vehicle also has a dramatically reduced view beyond the vehicle being followed, in this case specifically because of the bad weather so there may be no advanced warning.  See the article text.  (Copyright image, 2018.)

What both of the above sets of pilots didn’t mention, although their words implied it, was that ultimately their real error while driving was – dare I say – even more important than concentration.  For the answer to what this is, see  The Golden Rule of Safe Driving.

Photograph of a moving block / platoon of heavy traffic moving at 35-40mph.
Another situation where many drivers inaccurately don’t consider themselves to be ‘tailgating’ but this three-lane ‘platoon’ was travelling around 35-40mph so the average reaction time of 1.33-1.5 seconds would require a minimum of a 90-foot gap PLUS the necessary braking distance, so around 160 feet (or just over half an American football field). Collisions in these moderate-speed conditions are relatively frequent but less likely to cause serious injuries. The drivers at fault will inevitably seek to blame other people, not themselves. (Copyright image, 2018.)

By far the most comprehensive and research-proven driver training in the world, in relation to public roads, is correctly known as the System of Car Control, more recently also known by the acronym of IPSGA.  It has been developed since 1935 and is reviewed and upgraded by UK police advanced driving instructors as necessary, on an annual basis.

Obtaining advanced qualifications for the typical police scenario both for cars and motorcycles requires a minimum of ten weeks (400 hours) of full-time training, and this, in turn is anywhere from 2-10 times longer than it takes to obtain a Private Pilot’s Licence [PPL] and 5-10 times longer than the driver training for most U.S. highway patrol officers and state troopers, so it is easy to see that this is no small undertaking.

At the police end of such training is the need to be able to drive at extreme speeds on public roads, far in excess of the speed limits, in absolute safety, and this explains the need for such a lengthy regime.  However, “the System,” as it is often referred to, was adapted and made available for civilian drivers over 60 years ago, in 1955, and — uniquely in the USA – this is what we teach on our courses at Advanced Drivers of North America [ADoNA], obviously at much shorter durations starting at one-day courses.  The key point here is that your corporate or governmental personnel are taught up to 120+ important aspects of safe driving (not including the aforementioned high speed aspects!), depending upon the duration of the selected courses.  And if you’ve ever been told that only five or six key items need to be taught/learned to make a driver safe, you may wish to urgently reconsider that seriously inadequate claim.

So — briefly but importantly going back to the avoidance of tailgating — hopefully, by now, everyone will already be aware that what used to be referred to as the two-second rule has effectively been dead and buried for the last few years.  Because of the research on the reaction times of typical adult drivers, a full one-second needs to be added to those previous and now out-of-date guidelines.

Photograph of a pick-up truck tailgating a car.
Just a few feet behind at over 70mph — this really is tailgating at its least intelligent and most dangerous.  With a gap of no more than 20 feet at this speed, the ridiculously inadequate *time* gap between the vehicles is less than one-fifth of a second.  (Copyright image, 2011.)

Driving as so many drivers do, just a few feet behind the vehicle ahead is simply a crash waiting to happen, and drivers in the second and subsequent vehicles are the ones who unquestionably will be to blame.

Oh, and if anyone has ever talked to you about how many “car lengths” to leave as a gap when following another vehicle, please throw that information straight into the garbage.  It has always been ludicrously inadequate and dangerous.

At ADoNA, we therefore teach a three-second* minimum following distance, and how to get it right easily and simply every time.  Importantly, however, and for reasons mentioned above, we also teach safe variations for all weather conditions and for poor visibility.

*Note: Some organizations recommend a minimum of four seconds but that’s alright.  Although the fourth second is not actually necessary for a normal driver, there is nothing wrong with extra safety margin.

A small 'platoon' of cars, all tailgating each other.
Several drivers in the cars shown here have put themselves into an aggressively unforgiving situation, only one aspect of which is the fact that they are all tailgating. (Copyright image, 2011.)

The final photograph with this article, above, brings additional dangers into the tailgating equation, and naturally these, too, are covered during the training.

CEO Eddie Wren’s driver training and traffic safety résumé

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As always, please be aware that this website is registered with the United States Copyright Office and that punitive legal action for damages may be taken against anyone who breaches our copyright. This, however, does not stop you from posting links to any of our pages, and you are welcome to do so.

Author: EddieWren

Eddie Wren is the CEO and Chief Instructor at Advanced Drivers of North America. His driver safety background is given at: http://www.advanceddrivers.com/ceochief-instructors-resumecvbio/

13 thoughts on “Tailgating Doesn’t Apply to ME Because I’m a Good Driver!”

  1. Couldn’t agree more Eddy. A few years back I had the misfortune to be a passenger in a car driven by a serial tailgater, travelling in lane 3 at 70 +, only a car length from a Merc E class in front with an artic (semi) in lane 2 beside us. When I questioned the driver about his separation distance I got the classic ill-informed answer, “Oh I can stop, I am watching the car in front of the Merc” which was also being closely followed. Needless to say, I refused to be in a car again ‘driven’ by that individual. I put it down to the lack of Police patrols and the self-entitlement attitude that seems to be increasing year on year.

    I am aware we have had some harsh words for each other in the past but I agree with almost everything you put out on your site. Keep up the good work. There is not enough enforcement over here in the UK. Due, I believe, to my previous statement, self- entitlement together with diminishing Police presence on our roads.

    1. David, yes, the destruction of British ‘Roads Policing Units’ due to financial cutbacks has been extraordinary in its scale and has already been research-documented as having slowed down the rate of casualty reduction on UK roads, and it has taken us down the ladder a couple of rungs in the annual tables showing international success rates in road safety — a sad thing indeed given that Britain and Sweden were joint leaders for at least three decades.

  2. If all drivers kept a 3 second headway that would result in a per lane capacity on a freeway of 1200 vehicles per hour. Freeway designers and freeway operations personnel typically assume the per lane capacity of a freeway is 2000 vehicles per hour or higher. When designing freeways in Minnesota, we typically assume 1900 vehicles per hour for the right lane, 2100 for the center lane and 2300 for the left lane when there are 3 lanes per direction on a freeway. We have frequently observed higher volumes per lane per hour, in real traffic, sometimes reaching 3000 vehicles per hour in the left lane. To obtain this type of performance, a robust traffic management system needs to be in place which can then maintain speeds above 50 mph. With higher speeds, the vehicle itself, occupies less of the headway. Conclusion: in order to accommodate 3 second headways during peak hours, we would have to double the number of lanes on our freeways and if someone needs a 4 second headway, they should not drive on the freeway during peak times.

    1. That is perfectly true, Mr. Eyler, but with respect both you and I know that it will never even remotely happen because the majority of drivers very regrettably will continue to drive badly. The only **realistic** goal of true defensive or advanced driver training is to facilitate those individual drivers who have the correct attitude to be much safer, despite the bad driving that will continue to happen all around them. I’m sure you are also aware of the fact that when many cars are travelling too close, then two phenomena can occur. The first, of course, is that there is a collision and — setting aside the risk of casualties — the repercussions of this would inevitably be a significant interruption to the flow if the highway is busy at that time. The second is almost as bad because, as you no doubt know, when cars tailgate as a group it is common for one driver’s gentle braking to become the next driver’s firmer braking, and then the next driver’s hard braking and so on, until other vehicles stop, but without a collision. This is all-too-often responsible for the “phantom” traffic jams in heavy traffic and can stop large volumes of traffic for inordinate periods of time — again really not helping the flow to which you refer.

      Having occasional better drivers who maintain genuinely safe following distances within large platoons of vehicles not only benefits the safety of the individual drivers concerned but also inserts shock-absorbing gaps into the flow and this can both prevent collisions and reduce the likelihood of phantom traffic jams.

      Given the impossibility of ever getting all drivers to maintain safe following distance, I would genuinely expect traffic engineers such as your good self to welcome the inclusion of at least some safety gaps rather than focussing on the unrealistic scenario of the world being full of perfect drivers.

      Thank you very much for your welcome comment. I am grateful that you have raised the point.

      1. Eddie,
        First what you refer to as “bad driving”, I would describe as necessary efficiency. I would gladly add, that excessive lane changing during peak periods is bad driving and I will certainly grant you that maintaining a 3 second headway is safer for an individual driver. However, as I stated earlier, our freeways would then not have the needed carrying capacity. As a comparison, even in Germany, on their Autobahns, they expect drivers to maintain 2 second headways. But let’s go over the math and lets say we have a freeway with 3 lanes in each direction. At 3 second headways, that would mean that the freeway could carry 3600 vehicles per hour, per direction. With 2 second headways, it would carry 5400 vehicles per hour. If one then is able to enforce 3 second headways, to accommodate the 5400 vehicles per hour, it would require adding two lanes per direction. Our urban freeways in Minnesota typically carry over 6000 vehicles per hour. However, you do properly bring up the safety issue. So let’s say that freeway drivers do maintain the 3 second headways, then what happens to that traffic flow that is no longer being served on the freeway? It could be diverted to surface streets, if there is reserve capacity there. However, the crash rate on a surface roadway is 4 to 5 times higher than it is on a freeway. So if the freeway capacity is limited to 3600 per hour, I am sure some of that demand would be spread out over time resulting in a longer the peak period which could then be as small as 7.5% of the daily total. We have locations in the Twin Cities in Minnesota where the freeways are full for many hours of the day and the peak hourly flow, at capacity, only handles 7% of the daily demand. This then means that the freeway with 3 second headways would carry 48,000 vehicles per day in each direction. With our freeways typically carrying over 6000 vehicles per hour per direction and a peak that is typically 8.5% of the daily total, our freeways carry roughly 70,000 vehicles per day per direction. The two-way daily totals would then be 96,000 and 140,000 respectively. This is a difference of 44,000 vehicles per day that would need to find surface routes. Freeways typically have crash rates around 1.5 crashes per million vehicle miles per year and surface roadways with intersections with signals have crash rates of 6 to 8 crashes per million vehicle miles per year. So the 44,000 vehicles per day no longer carried on the freeway would experience more than 70 additional crashes per linear mile of roadway per year. The fatality rate on freeways is also much lower than on surface roadways despite the higher speeds. I therefore conclude, and the crash data backs me, that the more traffic that we can get onto the freeway, the safer our total roadway system becomes. It would certainly be nice to add lanes to our freeways, but the political will and the financing are often tough to come by. By the way, traffic signal engineers assume the capacity of signals at 1800 vehicles per lane per hour of green, or 2 second headways. You mention that freeway drivers who maintain 3 second headways provide “shock absorbing” cushions for traffic incidents. My experience has been that those 3 second headways will quickly turn into 2 – 1.5 second headways during peak periods. I will gladly agree that during lighter traffic flows, it is certainly sound advice to keep 3 or even 4 second headways. However, if anyone needs 3 second headways to feel comfortable and feel safe, then they should probably not use the freeways during rush hour.

        1. Dennis,

          It is a sad fact that whilst top traffic safety experts around the world have been urging us all to take a multi-disciplinary approach to reducing the catastrophic annual numbers of road deaths around the world, on the whole we sadly have failed to do so. If one looks to the so-called “E’s” of road safety, I recall that as a young traffic patrol police officer in the late 1970s I was just one of the single-minded clan who thought that “we,” the “Enforcers,” were the most important key to reducing deaths, and it is well-known that the “Educators” knew the police to be wrong because they were the main factor, and the “Engineering” people knew that both of the aforementioned groups were wrong, because only those engineers knew the best way forward! Yet, of course, all were wrong. It is completely unrealistic, in this more educated era, for any one group to still hold to our old and frankly naïve beliefs.

          I mention this, with no disrespect, because you are still clinging to flow-figures despite previous mention of the fact that there is no way that even a majority of drivers, let alone all of them, will ever drive well enough to even care about safe following distances. Around 94 percent of all road crashes in the USA involve driver error (although “only” 56 percent are due solely to driver error – a difference which I know you will understand), and these figures will only be reduced significantly when truly-safe, fully-autonomous vehicles are in universal use, something which in its entirety is undoubtedly still several decades away, despite the crowing of companies seeking huge investments.

          I must add that the apparently low number of deaths per million VMT per year really, really fails to impress me because, inter alia, the USA has long been effectively the most dangerous developed nation in the world in terms of road deaths, by a very large margin, including the rate of deaths on divided highways.

          Amongst many other sources, see: http://www.advanceddrivers.com/2018/07/09/international-road-safety-annual-report-2018-the-usa-does-very-badly-again/

          I can therefore only ask you once more to kindly forget about the entirely fallacious scenario of everyone ever leaving safe headways and spoiling highway flow targets. It will never even remotely become a consideration, and when autonomous vehicles eventually become the norm, the un-concentrating, distracted human brain will have been removed from the equation and close-travelling platoons will be entirely feasible — presumably increasing the potential flow figures.

          As I have previously stated, our type of defensive- and advanced driver training work can only ever be effective for those individual drivers who recognize the dangers and are actually willing to make the mental effort to greatly reduce those dangers in relation to their own loved ones and themselves.

          As for our recommendation of a three-second following distance, please be aware that we are by no means the only ones promoting it. Major road safety organizations around the world are now fully onboard, and here in the USA that includes The National Safety Council (3 Seconds) and the AAA Foundation for Traffic Safety (4 seconds).

          1. The goals of your organization are certainly laudable.

            However, I have worked both as an employee and consultant to agencies designing and operating freeways and surface roadways. As operators, our goals are to operate the roadway systems that our funding and political systems provide both safely and efficiently as possible. Until autonomous vehicles are perfected, our tools will be freeway management systems that do attempt to promote speed harmonization and also to manage flows by the use of metering to keep the freeways flowing as close to capacity as possible. For controlling junctions on surface roadways we are increasing the use of roundabouts, which do have a proven safety record, but in some cases do not provide sufficient capacity for the space that is available. For those intersections needing signals, there is certainly much room for improvement in the way they are designed and operated in many parts of the United States. In Minnesota, our signals have a low rate of fatal crashes for signals. Our average fatalities per year are less than half of the U.S. average. A recent typical year has been 25 fatal crashes at our over 4000 signals, many of those crashes are a result of impairment, not problems with the signal. There are more deaths from motorcyclists not wearing helmets than there are at traffic signals in Minnesota. Our signals on high speed roadways (50 mph+) have proper vehicle detector placement for dilemma zone protection and our yellow change intervals and all red clearance intervals are properly timed for those speeds. In addition we also make use of dynamic end of green warning flashers.

            I have had my drivers license for 55 years now and I have driven in over 25 countries, both on the left and on the right and personally, I probably keep 3 or 4 second headways when I am driving on rural freeways with lower volumes.

            However, I feel that during peak periods, on crowed freeways, unnecessary lane changing is more of a problem than shorter headways. One of our goals as freeway operators and designers is to reduce lane changing and promote laminar flow.

            In conclusion, I would ask your opinion on states like California that have lower speed limits for trucks. I frequently visit California and when driving on their rural freeways, with only 2 lanes per direction, every truck is effectively a rolling lane closure where the auto traffic has to squeeze into the left lane to get by and then fan out again to use both lanes after passing the truck and a truck passing a truck sometimes takes several minutes. I do not see similar problems on freeways in states that do not have lower truck speed limits.

          2. Firstly, my apologies for the delay in making this reply; it has been a busy few weeks.

            I think we have to recognise the simple fact that engineers’ needs for maximum traffic flow are exactly that, and they do not necessarily reflect maximum safety. Those of us in specific traffic safety fields on the other hand, with no disrespect, have little or no interest in traffic flow and focus instead upon minimising the number of dead or injured bodies. It is not hard to see that these two goals cannot always happily co-exist. They key thing I ask you to remember, however, is that training bodies such as ours barely even scratch the surface of the nation’s population of drivers, and of course not every driver we train will have sufficient motivation to continue doing what we teach! Well trained drivers on America’s roads are outnumbered by many thousands to one, so our work is **never** going to impact on your flow figures, other than the fact that drivers deliberately leaving a safely adequate headway will occasionally prevent a concertina-style collision and therefore on those occasions prevent some of the terrible traffic jams that can follow a crash.

            You are undeniably correct that unnecessary lane changing is a significant problem, although I would suggest to you that many of those who use this method to weave selfishly and dangerously through traffic are also amongst the most egregious tailgaters.

            You ask about our opinion on ” states like California that have lower speed limits for trucks.” Well, coming from England where we have always had different speed limits for trucks, combined with relatively very busy motorways, divided highways and undivided roads (bearing in mind that Britain has one-fifth of America’s population but in a country that is only 1/36th of the USA landmass) it is my opinion that the different speed limits are a safety-plus rather than a safety-negative. If I remember correctly, around 4,600 people are killed in the USA each year in collisions involving heavy trucks (it is certainly well over 4,000). It is my belief this extraordinary figure is largely related to the speeds that trucks are permitted to do. Certainly, the use of passing lanes for cars to pass slower trucks is not a significant cause of crashes on UK roads but I would suggest that the significantly higher standard of student/learner driving in Britain may have a part to play in that.

        2. Mr Eyler,
          Perhaps Eddie will allow me to interject. On the measurement of those traffic ‘flow rates’ there is no account of an interruption. To achieve the high flow rates, drivers will be travelling at unsafe following distances, which will lead to collisions. The flow rate during the time it takes to clear the roadway will be greatly reduced in all the travel lanes in both directions! If those delays were added to the calculus then I think you will find that the ‘flow rates’ with unsafe following distances are a lot lower than designed.
          Since I try to maintain a 3 second following distance I do experience other drivers who ‘cut in’. During my regular 330 mile journey from Southern California to Northern California this can happen up to 30 times (generally around 10) Since those drivers typically tailgate with 1 second or less following distance it ‘costs’ me about 30 seconds on a six hour journey. If there is a collision, the cost is usually 30 minutes or more, the worst delay due to a single collision was over 2 hours.

          1. I would suggest you contact Brian Kary at the Minnesota DOT’s Traffic Management Center. He can supply you with the day in and day out peak period lane by lane flow rates. The MnDOT traffic management center has an extensive system of traffic detectors and TV cameras that monitor traffic flows and supply data to the computers operating the ramp meters and dynamic traffic signs. Here is his e-mail:Kary, Brian (DOT) (Brian.Kary@state.mn.us) He can also provide you with additional information regarding freeway traffic flow theory.

            During my career I was involved with the development of some of the early efforts of computer simulation in the early 1990’s. Later, along with other staff members at SRF we performed many freeway operations evaluations for MnDOT using micro-computer simulation with a product developed by the Federal Highway Administration (FHWA) called CORSIM. We also have completed many simulation projects using software developed in Germany called VISSIM. We are required by the FHWA to use real traffic flow data to calibrate out simulation models.

            I have one final calculation involving daily traffic volumes to share. On I-94 between downtown Minneapolis and downtown St. Paul has an average annual daily volume of 155,000 vehicles per day which is carried in 6 lanes at Snelling Avenue. That’s an annual, day-in, day-out average of 25833 vehicles per lane per day. If 3 second headways (1200 vehicles per hour per lane) were somehow to be maintained, it would take 21.5 hours of constant flow at that rate to carry that traffic. I-94, on an every day basis carries around 2100 vehicles per lane per hour during the peak periods. That freeway probably flows near that rate for more than 3 hours each way during each peak period. The question would seem to be where would those 900 vehicles per each of the 6 lanes then travel if not on the freeway?

          2. Perfectly true, John. This subject was addressed in detail by Leonard Evans — the former engineer in charge of safety at General Motors — who discussed journey delays in his book ‘Traffic Safety’, in exactly the same way you just have, and he came to exactly the same conclusion of any resultant delays being absolutely trivial.

          3. I did a quick follow-up by looking at data from the I-405 in west Los Angeles. During the heaviest traffic hour on section 8 of I-405. (I-10 to state route 2) 21,000 vehicles pass through this section of freeway during the busiest hour. This traffic is distributed over 14 lanes. which gives us an average flow rate of 1500 vehicles per hour per lane. This is on the busiest section of the busiest freeway in North America. The data was gathered over several months form October through January over several years. This is not too far removed from the 1200 number and does account for the delays.
            http://www.laalmanac.com/transport/tr26b.php
            http://www.dot.ca.gov/dist07/divisions/planning/cm/FINAL405TCR.pdf

        3. Dennis,

          Further to our initial discussion about headways / following distances, the article (with video) below has coincidentally been published recently. I would add, however, that on this specific topic Britain has frankly failed to keep up with research on reaction times from bodies such as Monash University, and unfortunately is still recommending a minimum two-second headway rather than the much safer three seconds.

          Highways England launches campaign to stop tailgating – https://www.bbc.com/news/uk-england-45545525

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