INeedAttention.com

I haven’t posted on Fark, or my own website for that matter, in quite a while. I figured that since threads about driving and highway design are some of my favorite that I’d throw in what I know.

In states where there is no explicit “keep right” law, it boils down to common courtesy, as has already been said. Part of courtesy is cooperation from parties driving both above and below the speed limit. The road belongs to all of us and is something to be shared, not something to be won, and I think that we all can agree that judging from this thread — many drivers disagree on how to coexist on the roads. Some would like to move faster and some would like to move slower, but realistically neither is more correct; drivers from both sides need to just have more of a “let it be” attitude.

This brings me to the next point, regarding stop-and-go traffic. Comments were already made in this thread by I’m_a_moran regarding this type of traffic and how it can be modeled with waves. They are correct to say that leaving a reasonable gap, and observing a safe following distance ultimately improves traffic flow for drivers behind you. The cause for these improvements is that a) by driving at the overall average speed of traffic, you drive neither significantly slower nor faster than stop-and-go traffic would permit anyway, and b) by continuing to move and not be forced to stop, if a temporary bottleneck or other cause of traffic is reached, people allowing adequate following distance that choose to cooperate can temporarily share a single lane by merging together seamlessly and parting after the temporary blockage has eased. Consider a zipper as a model of this concept being idealized.

Allowing for a safe (and generous) following distance does not, in fact, cause the traffic problems; it’s actually quite the opposite. In the UK, for example, there are roads with dynamic speed limits (and the speed limits in the UK are often automatically enforced, mind you) — the idea being that drivers adjusting to an appropriate average speed in traffic ultimately improve flow for others. The driver that waits to allow space to form in front of them does wait, yes but as the wave of braking forms behind them, there is a “crack the whip” effect that travels through the road until either there are no vehicles left to brake or until space between vehicles is adequate enough to allow vehicles to comfortably coast to a slower speed (and thus join in the slow down, which often is inevitable and merely a result of congestion). As far as that little bit of roadway that appears to be idle and wasted, it’s really not. Its emptiness is only transient, and furthermore the few seconds that is it empty for will be followed, hopefully, by scores of other drivers calmly rolling over it at a constant reasonable speed, rather than the traditional 0mph one moment, and 30mph the next. What it really boils down to is: would you rather drive somewhere going 30mph for half the time, and be completely stopped for the other half the time, or would you rather drive 15mph the entire way? I suppose there are some people that would say they’d prefer the former, but its certainly far less stressful to the highway, the vehicle, and the driver by the latter.

Drivers interested in becoming “lubricators” to the flow of traffic can do more than just allow for a safe following distance.

First, go with the flow! Regarding speed limits and flow, drivers are better off following the flow of traffic. If nine out of ten cars around you are driving faster than the speed limit, its better to move with them than against them, and vice versa for slow moving traffic.

Next, be eager to say “go ahead!” When another vehicle is trying to change lanes, exit, merge, or perform any other maneuver that requires cooperation from other drivers, be the driver that allows them to perform their maneuver. The caveat to this is that occasionally, drivers dont expect you to be courteous and actually get confused by being let in. If the other driver doesnt understand your gesture after a second or two, its not your fault, just move on. To effectively permit lane changing and merging in an optimal fashion, you should only accelerate slightly or coast. Accelerating or braking abruptly obviously runs counter to every other suggestion made here.

Also, avoiding braking (primarily by avoiding tailgating and allowing an ample following distance) should be your goal. Obviously, this doesnt mean that if youre about to slam into the person in front of you that you should do that (or jerk the wheel to the side to change lanes at the last second). The idea here is that you should try to find the average speed at which traffic is flowing, and then drive at that speed. When you see a serious slow down far ahead of you, just start coasting, and dont worry that some people behind you will pass you. They ultimately will end up stopping just as you do, but in your case, the cars behind you that do realize what youre doing will also roll to a gentle stop (or perhaps wont have to stop at all if you time it right). Another unintended positive side effect of this is that your vehicle will wear at a slower rate. For example, I drive a 1993 Mitsubishi Diamante, and my tires have lasted as long as 60,000 or 70,000 miles from a combination of easy driving and proper tire care (for comparison, the average is about 45,000).

Finally, dont compete with other drivers, and especially dont try to punish them. Everyone knows thats far more dangerous than driving too quickly or too slowly. No insignificant amount of headway on a highway is worth causing an accident over.

There are also scores of other things that drivers could do, but the ones that Ive listed are what came to mind first. Just remember: most of the time, its not a big deal when someone is moving a bit slower or faster than you. There are both drivers that drive dangerously fast and slow, and these drivers are targeted by law enforcement more frequently than the average driver. Our systems for mitigating the risks caused by such drivers are admittedly not perfect. The things that we can each make better, however, are our attitudes.

Can’t we all just get along?

Related links:
Traffic Wave Experiments
Lifes Little Questions: Why Does Traffic Jam?
Microsimulation of Road Traffic
TrafficWare Software, makers of Synchro and SimTraffic

Two serious accidents occurred within hours of each other yesterday less than 1000 yards away from each other around exit 12 on Interstate 87 near the Palisades Center in West Nyack, NY. In the first, an 11 year old boy was killed and his family seriously injured when another vehicle crossed the median and crashed into their vehicle. The driver and passenger in the other vehicle suffered non-life threatening injuries. The cause of the second accident, pictured here, has still not been determined.