Lane Discipline and Why It Is Important

Lane discipline isn’t just keeping between the white lines. Here’s what you need to know in order to stay safe and keep traffic flowing.

Knowing Your Lane

Among the differences in driving cultures between the Europe and the US, like which side countries choose to drive on or what’s a reasonable size for a family vehicle, none is as stark as lane discipline. In fact, while most drivers in the UK and continental Europe are taught to strictly adhere to proper lane discipline, few American drivers even know what the term means.

It does not simply mean keeping within the white lines of your lane (lane integrity or orientation). Instead, lane discipline covers lane integrity and using the appropriate lane for any given situation. A common misconception remains that on roads with multiple lanes, the right is for slow traffic and the left is for fast traffic. This misconception results in traffic disruptions, frustrated drivers, and unsafe driving situations. But when drivers observe proper lane discipline, the flow of traffic is eased, tensions dissipate, and everyone gets to where they are going safer and more quickly.

Rather than dividing the lanes as “fast” and “slow”, the right lane is for normal driving while the left is for passing. We’ve all seen it, and likely even been guilty of it; driving in the left lane long after we’ve passed other traffic, or worse, when we’re not even passing other cars at all. This is the big no-no of lane discipline.

Lane Discipline, the Right Way

So why do traffic engineers and driving instructors want you to keep right? Because it’s both safer and allows for better traffic flow. Driving in the left lane, even if you’re going faster than the regular flow of traffic means you’re gumming up that lane for other drivers looking to pass. Worse, you might not be going all that much faster than traffic, if at all. Not moving back over and maintaining lane discipline can cause traffic to back up. And finally, driving in the left lane at the speed limit prevents other vehicles from safely passing not just other flowing traffic but slower traffic as well, further slowing things down and potentially creating unsafe situations.

Here’s our guide to proper lane discipline:

Stay in the middle of your lane. Avoid meandering from one side to the other. Do not crowd the center line or nudge too close to the road’s edge.
Adjust to road conditions and hazards. Keep a careful watch for potholes, construction, and other hazards that might call for a lane change or other deviation.
Know your exit and plan accordingly. Whether on a multi-lane interstate or in town, it’s important to know when and where you plan to exit. Being attentive to other vehicles and proper signaling are keys to safely arriving at your destination.
Flow with traffic. One of the cardinal sins of poor lane discipline is not picking a lane. Some drivers, in an effort to gain a slight edge, will make frequent lane changes to get ahead of slower traffic. Not only is this dangerous as your movements will be unpredictable for other drivers, but you don’t often make much if any gains in time or distance by bouncing between lanes.
Remember, the left lane is for passing and the right is for driving. Do not hang out in the left lane.

Zipper Merging

A related topic, zipper merging both eases traffic congestion and increases safety (when done properly). Situations that call for a zipper merge often occur in dense urban and interstate traffic that constricts from multiple lanes down to fewer or one. Road construction is commonly accompanied by preceding signage indicating a lane closure. Most drivers see this sign and move over immediately into the lane that will stay open. This is wrong.

While the phrase “get while the getting is good” might seem to apply, according to traffic engineers, it does not. Instead of immediately getting into the future open lane, drivers in the closing lane should continue in that lane until they arrive closer to the merge point, then signal and move into the open lane. This allows a given section of road to carry more traffic. If all the cars immediately move over, the line of traffic backs up considerably (practically doubling or nearly so).

There are two hurdles to properly executing a zipper merge. The first is that a zipper merge requires other drivers to be both attentive and polite, things often in short supply on your daily commute. The second is the understanding of other drivers (also in short supply). This is because most drivers will, mistakenly, move over while you continue on down the road, only to attempt what they might consider a late merge. The automotive equivalent of butting in line.

Therefore, while the zipper merge is the preferred method for merging when lanes converge, it must be done with caution and humility. Do not go speeding past a line of backed up traffic only to wedge your BMW X5 in at the last moment. Finesse will be key.

With that said, the more drivers know about proper lane discipline and zipper merging, the better traffic will flow.