If you've lived around the two-lane highways of Charlottesville, Virginia, you're probably intimately familiar with the conga-line of cars that regularly materialize in the left lane, known as the "passing lane". This phenomenon is an example of what happens when a system has a bad reinforcement loop. Systems, alas, are no better than the sum of their parts. And no self-sustaining system can thrive when its rewards are out of line with its goals.

In February 2017, the House of Delegates approved a bill that would impose a mandatory $250 fine for driving too slowly in the left lane on highways.


In the state of Virginia, we are legally required to move to the right lane if blocking traffic. This, essentially, means that you're allowed to be in the left lane until someone wants to pass you, no matter how fast they are going. In fact, in February 2017, the House of Delegates approved a bill that would impose a mandatory $250 fine for driving too slowly in the left lane on highways. Yet, far too few policemen even enforce this. What's worse is that even if they wanted too, it's only apparent that a driver is breaking this law when there's already a backup of traffic which makes it hard for a policemen to get through. Moreover, with Virginia straddling Maryland and North Carolina, states that have no rule for lane courtesy, it only adds to the chaos.


Rules of a system should cater to its player's motivations. What do people want and how are they achieving them?

Safety is the main concern for most people when entering the motorways. Drivers who are concerned with safety generally go slower, avoid changing lanes and pay attention while driving. While everyone should be worried about safety while on the road, this motivation is especially apparent in new drivers and older drivers that have a fear of merging.

Time is the second most common motivation. Drivers who are concerned with time often end up driving faster. However, though speeding gets a bad reputation, people who speed usually are paying more attention (for fear of policemen as well as the increased speed at which they have to make decisions) and are rarely the cause of traffic jams unless they've caused an accident. Accidents which are usually caused by aggressive drivers tailgating or natural forces. Fast drivers and aggressive drivers are not the same.

Cost is the third most common motivation. Drivers who are concerned with costs often drive slower, avoid braking or accelerating too much and try to stay in their engine's sweet spot. This sometimes leads to drivers that never successfully pass that car they intended to pass since they are so fixed in their ways. You see this a lot with trucks.

Other than ignorance, there's one more subtle motivation that drivers experience when on the road. It's a feeling that while you're on the road, you're wasting time. Time that could be used to do something else. This leads to people "zoning out" or distracting themselves with phone calls, podcasts, audio books and even videos or movies. Distracted drivers check their mirrors less often, change lanes less often and obviously, pay less attention to the road.

Taken in concert, three of these four motivations lead people to the left lane not including ignorance. Safe drivers for fear of merging with cars entering the motorway, fast drivers to pass and rather-be drivers to "zone out" and cruise. While all drivers have a mixture of these motivations, looking at them independently allows us to understand the system in a simpler scope. For instance, taking our Virginia state law into consideration, two of the three motivations that bring people to the left lane would in one way or another block traffic in addition to cost drivers. Rather-be drivers because they would be too distracted to notice an approaching vehicle, slow drivers because they may be going slower or equal to traffic but sometimes will speed out of the way and worse, cost-drivers for the same reason but will most often not speed out of the way to save gas. Once the flow of traffic is slowed, cars, for fear of getting caught passing on the right, will assemble themselves in our so called "conga-line" and the car leading the way either isn't aware or doesn't care. Sadly, unlike a speedy driver not caring that he's breaking the law has to remain vigilant to escape detection, a driver backing up traffic has nothing to be worried about because policemen can't even reach them to enforce the law.

The Autobahn

Let's take a step back and look at a system that does work, the German Autobahn. These motorways are famous for their lack of speed limits. Drivers regularly travel more than 100 mph (~160kph) yet the Autobahn is also known for its insanely low number of accidents. Why is that?

First off, the Germans have a few rules (e.g. keep right) and everyone knows them. Secondly, they strictly enforce these rules and lastly, because everyone knows these rules and obeys them, newcomers are easily indoctrinated. More subtly though, because the road ways are more dangerous, it, almost incomprehensibly, makes it less dangerous. Just as a surfer learns to respect the ocean. This shared attention, respect and freedom to do what's right leads to a safer road. There is no "normal flow of traffic", no thought that because you're already going 5mph above the speed limit that others wouldn't and shouldn't need to pass you because they would be going too fast. Instead, you find yourself gauging what needs to happen for you and others, freely accelerating to remove a bottleneck and accepting that anyone around you can pass you at any moment and allowing them that opportunity.


Another functional system can be seen in the streets of Vietnam. These roadways are spectacular because there are almost no rules. Mopeds flow like droplets through a stream absorbing others without hesitation. In fact, that's actually how it plays out. Drivers are responsible for the cars and motorists in front of them, there are rarely lanes other than the center dividers (which are only suggestions) and though there are speed limits, the roads, your vehicle and the unpredictability of the environment serve as the barrier to your, otherwise, unmitigated accelerations. Once you accept that there are essentially no rules and that anything can happen at anytime, your focus shifts from yourself to others. You easily accept the fact that motorists join the freeways without looking over their shoulders, trusting that their neighbors (you) will notice them and give them room. In some locations, farmers are drying their grains on the roads while motorist speed by. Traffic jams turn into a free-for-all where any hint of pavement becomes a part of the flow of traffic.

This system, though seemingly dysfunctional, arranges itself around natural laws. Laws governed by the terrains of their roadways, the vehicle of choice of their population and a respect for the dangers that these entail. They all function together to keep roads safe and keep traffic flowing.

What can I do?

With our current laws there's some facts you should know that can help you be a better, safer, more courteous driver.

  1. The left lane is a passing lane, so please stay to the right unless passing. Lead by example.
  2. You are allowed to exceed the speed limit to pass and avoid a harmful or dangerous situation.
  3. Flicking your headlights is a gentle way to pull a drivers attention back to driving to let them know you want to pass. However, during daylight, this is less noticeable.
  4. Honking is a bit more harsh, yet sometimes necessary tool in getting a driver's attention. If you're the second car in the conga-line, it's your responsibility to get the first car out of the way. If you're the first, shame on you!
  5. Keeping your left blinker on in the left most lane suggests that you want to pass. This is common in Europe, though rare in the U.S.
  6. Tailgating is extremely dangerous. With that said, tailgating is a symptom of drivers not following the rules, keeping right and having the courtesy of speeding up while passing. Before tailgating (and risking your life), attempt #3, #4 and even #5.
  7. Panic lights should be used preemptively to warn drivers behind you whenever traffic ahead has slowed down drastically.
  8. Use your blinkers when merging and turning.
  9. Merging is one of the leading causes of traffic, usually caused by a decrease in lanes. Therefore, rather unintuitively, merging preemptively in traffic jams helps to move everyone along. Avoid the temptation to go speeding down the empty lane, which selfishly helps only yourself.
  10. Stabilizing stop and go traffic by yourself going a constant speed can help move everyone behind you along.

Wrapping it up

Speed limits are not necessary anymore. People's respect for the roadways, just as the surfer respects the ocean, it's power and it's unpredictability, will and should guide their decisions. Speed suggestions, on the other hand, provide people with information about the coming road conditions and trust that they are smart enough to make an educated decision. We need to make systems that celebrate our intelligence instead of trying to control our stupidity.

We need to make systems that celebrate our intelligence instead of trying to control our stupidity.

In terms of our motivations, removing speed limits (without any other amendments) would keep safety and cost conscious drivers on the right, since cars would be speeding past them to the left or send them to alternate routes. It would allow people to drive however fast they deemed fit, at times saving us from traffic jams or accidents which would keep the focus of the distracted drivers and allow speed drivers to do what they do naturally. It would also remove the emotional frustration that aggressive drivers acquire from being stuck behind a "slow-poke" and would, through all this, make our roads safer.

Keep right except for passing

However, should that not be an option, simply amending our lane courtesy law could be a nice first step to make things easier for drivers and police officers. Adopting a law that removes the doubt from a police officer as to whether a driver knows the law or not so that offenders can be caught and fined or educated before traffic begins to pile up behind them. A law that is so simple that it leaves no room for interpretation. A law that creates a culture of courteous driving that becomes contagious to new drivers by simple observation.  A law as simple as "Keep right except for passing."

Simulator (Work in progress)

I've taken the liberty of creating the traffic simulation below. While it is still a work it progress, it helps to illustrate some points about traffic. Currently, all cars are coded to respect the idea of "keeping right except to pass", however, they don't courteously speed up when doing so. Adding controls and settings to augment the simulation as well as concepts like motivation (speed, safety, cost and distraction), pressure, blinkers, acceleration and overall vehicle intelligence are in the works. Inspired? Fork this Pen and enhance it!