The University of Michigan's Transportation Research Institute have released the prosaically titled report "The Effect of Lead-Vehicle Size on Driver Following Behavior." Its authors gave randomly selected drivers (Hey! You!) video-equipped cars for two to five weeks, and then studied their driving behavior. The result: passenger car drivers followed light trucks at shorter distances than they followed passenger cars by an average of 5.6 m (18.6 ft), but at the same velocities and range-rates." Bizarrely enough, when drivers could see through, over or around lead vehicles, they maintained significantly longer (i.e., safer) following distances. The study's authors have a message for truck-tailgating drivers: being able to see a big ass vehicle's stop lights ain't enough. Back off jack. (Only in more scientific language.)
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There are several good reasons for doing this. For one, it serves to notify the slow moving SUV/Truck that you would like them to get out of the fast lane as they are being passed on the right and not properly utilizing the passing lane. Second, it allows you to scoot to the side and see around said slow moving SUV to verify there isn’t a line of traffic in front of them actually causing this obnoxious slow speed.
Interesting phenomenon. Maybe the driver of the passenger car, sensing blocked visibility, in effect tucks in behind the truck and lets it run interference. The car driver may feel safer that way.
Third, you get greatly improved gas mileage drafting through the hole the gargantuan SUV punches through the atmosphere. See, they really are good for the environment!
[Facetious emphasis added.]
This may actually be rational behavior. SUVs tend to have longer stopping distances than cars. Which means that you don’t need as much distance between you and the SUV in front of you, since they cannot out-brake you.
I drive a Trailblazer SS (400hp LS2). I don’t notice anyone close behind me. I do notice a lot of mini vans, conversion vans and Suburban size SUVs crawling along in the fast lane. Lane discipline would alleviate this problem to a great extent.
That is an interesting result. With many SUVs it doesn’t matter how far back you are, you still can’t see around it. I wonder if the behaviour is a sub-conscious (or conscious) desire to be in front if the SUV and our brains equate being close behind to being closer to “in front.”
It would be fascinating to see some follow-up research that tries to determine why we do this.
Not having RTFA, I would venture that people tend to tailgate larger vehicles BECAUSE they cannot see the traffic flow ahead of the behemoth and assume (not always mistakenly) that the SUV is simply driving slower and not with traffic. The presence of a large non-moving (relatively to the driver of the trailing car) ass-end of an SUV can also give the impression of a lower speed than is actual, much like fog.
This is an interesting observation and I’ll have to observe my own behavior on this one. Scottb’s last comment (just above) seems the most logical to me, along with the idea that people follow SUVs closely so they can get around them. I will often pass an SUV just to get a better view of the road ahead. THe biggest reason I hate SUVs is that I hate having my view ahead blocked by them.
I would agree that many, if not most, of the tailgating drivers simply want the SUV or truck to move out of the fast lane. While it’s certainly not true that all SUVs or pick-up trucks hold up traffic, I can say anecdotally that these vehicles appear to make up a disproportionate amount of those that shouldn’t be in the left-hand lane. At least in my neck of the woods. And I say this as the pround owner of a Ford Ranger.
It is an interesting result. I wonder if they did the study in Michigan? I’m sure we have the highest % of tailgaters in the nation, and the closest tailgaters. Many people here seem to think half a car length is adequate at 70mph.
Watching other drivers it’s clear that many are not looking more than two car lengths ahead no matter what is in front of them.
I guess I am one of those tailgaters. I hate not being able to see the road ahead when a larger vehicle is in front of me so am always looking for an opportunity to overtake. I guess I should get an SUV too.
Wow, these are very interesting findings. I always feel like I’m riding an SUV’s ass, then I realize that my following distance is actually farther.. but not far enough. You realistically must maintain at least twice the following distance behind an SUV –just to be able to see traffic lights and such.
same goes for the caliber :P but I like to stay as far from those as possible, else my Protege5 must catch the plague.