Three lanes are always better than two but environmentalists are against expanding from two lanes to three lanes because they say that having three lanes will promote the use of the car. I believe that this is a flawed argument.
The A1 motorway between Geneva and Lausanne is often congested because when a slow vehicle wants to overtake a slower moving vehicle it blocks the motorway as can be seen in the video included within this post.
On a three-lane motorway you have the slow lane for slow vehicles, insecure drivers and stoned people with no rush to get anywhere. In the middle lane you have those who want to drive at the speed limit without having to slow down and accelerate all the time. In the left lane, you have all the cars that want to overtake everyone else.
In a system with three lanes, there are three options, and these three options usually ensure that all cars are going at the speed that they are restricted to, or feel comfortable with.
In a two-lane system, these three groups of drivers are stuck in two lanes, but in reality, you only have one lane, the fast lane. The problem with having just two lanes is that if you’re in the right lane you will need to move out and back in constantly as you are expected to do.
Frequently when you do this you find that you are constantly having to go from 100-120km/h burning a lot of fuel constantly accelerating and decelerating. The reason for this constant change of speed is that you’re constantly getting blocked by cars in the right lane either driving too fast or too close to each other. This is another behaviour you see in the two-minute clip.
This results in large stretches of the motorway being empty. As two slow vehicles overtake faster vehicles are unable to overtake and the density of traffic behind the slow vehicles increases. As soon as the slow vehicle has finished overtaking vehicles able to go at the speed limit accelerate and the accordion of traffic expands again.
In a three-lane system, the accordion has less chance to occur resulting in greater fuel economy as cars stick to a steady speed.
I filmed the motorway as a distraction during a walk, not expecting to get such a clear illustration of how easily congestion occurs on a two-lane motorway.