People will have their opinions, usually with logical-sounding rationale behind it. Back just before I got my learner's permit I began to get interested in the nuts and bolts of how to drive a car, because it was something that was quickly approaching as I got closer to my 16th birthday. I would pump whoever was driving the car with questions about why they were doing that they were doing, at the time they were doing it. One of those questions was why they were in the lane they were in. One of my cousins gave an answer that made the most sense to someone who didn't yet drive, and it turns out to be the right answer.
When you have a choice between a controlled access highway (freeway, Interstate, etc.) and a boulevard with lots in intersections and shopping parking lots with people entering and exiting the road all over the place, you'll generally want to choose the controlled access highway because it minimizes the interactions and thus the chances for an accident. The three (or more) lanes on an Interstate present the same scenario, where each lane presents more chances for interactions and accidents.
In the right lane, you have people exiting the highway, some of whom will slow down often without warning. You also have people in the center lane sometimes changing lanes to the right lane at the last possible second in order to exit the Interstate. In addition, you have people entering the Interstate on the entrance ramps which present interactions from those speeding up or slowing down or changing lanes to accommodate the merging traffic. In the right lane, while you do have an "out" on the shoulder, you're dealing with some merging traffic from the right, and an entire lane of traffic to your immediate left that you have to deal with and be defensive about, there is usually heavier traffic in the right lane, and also, possibly the most crucial factor, the wildly varying speeds in your lane due to merging traffic and people changing lanes at the last second.
In the center lane, as IRT noted, you lose your "out" in case of an emergency. Also, now you have to deal with traffic not just to your left but also to your right. You'll have sudden lane changes from both side to get into the center lane that you have to deal with. You're moving in the out of blind spots of drivers in the left and right lanes, as well. Every lane change and pass presents an interaction.
In the far left lane, you generally have your "out," you rarely have merging traffic or exiting traffic to your left, and you only have to deal with moving traffic to your immediate right. The far left lane clearly presents the fewest interactions and opportunities for accidents.
So, when you think it through logically, the left lane is the safest, the middle lane is less safe, and the right lane is the least safest lane in which to drive.
So then, you look at the actual data from the National Highway Traffic Safety Administration, see how it stacks up with some logic and critical thinking. As part of their
National Automotive Sampling System (NASS) have the Crashworthiness Data System, which is the detailed data on a representative, random sample of thousands of minor, serious, and fatal crashes. The NASS CDS doesn't specifically track lane of travel for accident data, but the accident narrative reports do list the lanes of travel when the lanes are known. Approximately 30% of the narrative reports (100,000 reports give or take) list a lane of travel as being pertinent to the accident.
Of the lanes listed, accidents in the far right lane represent 46 percent of the accidents, the middle is at 37 percent, and the left lane is at 17 percent.
Those percentages compare quite nicely to the 'opportunities for interactions' logic - the lane with the most opportunities for interactions, and thus the least safe, is the right lane, followed by the middle lane, and finally the left lane being the safest.
What most people do, however, is when there are three or more lanes, is use the right lane when traveling at a slower speed than traffic, the left lane for passing, and the center lane for cruising. If
everybody did that, there wouldn't be very many accidents. But some in the right lane tend to speed, passing center lane vehicles on the right, even thinking they can speed almost at will in the right lane because they won't get a ticket (because they're not in the left lane), and others who are in the center lane who don't drive at a consistent speed (or too slow of a speed - impeding traffic) because they figure if someone wants to go around them there are two other lanes to choose from (not realizing that big trucks cannot use the left lane at all and in most states it's illegal (tho rarely enforced) to pass on the right). These people who hang out in the center lane and impede traffic make an almost conscious decision to not be courteous, even though they think they're not being rude and inconsiderate at all. Because they're in their 'center lane comfort zone' it creates the habit of
not changing lanes (sometimes not ever, almost defiantly), and
not looking into mirrors and they tend to stop being aware of the traffic around them.
But it's important to keep in mind that the above percentages for the three lanes are for those who were involved in accidents, not for everyone traveling on he road. They don't necessarily predict a likelihood of an accident. The primary factors in having an accident, regardless of lane, are speed, speed differential between you and others around you, and the amount of traffic on the road. A major factor which cannot be dismissed is the lane percentages also correspond quite accurately to the amount of traffic each lane has. Simply, the left lane has far less traffic so it will naturally show a lower percentage of accidents than the other two lanes. The center lane as more, and the right lane has the most traffic. But the numbers do make it clear enough that the left lane is the safest, then the middle, then the right lane. Just as important as the numbers, however, is the essence of good driving is not adhering to a hard and fast set of rules, but driving with common sense and courtesy. Sometimes you don't want anything to do with the left lane, despite is being the safest lane, and it's the right or middle lane where you should be.
In heavy traffic, I tend to stick to the middle lane and use the left lane for passing, moving back to the middle lane to let those who must exceed the speed limit to pass me in the left lane. If the left lane is moving along at the speed limit without a lot of speeders I'll usually stay in the left lane, because it's safer.
