What is the best way to drive in traffic? --bumper-to-bumper or allowing some space?

April 27, 2012 8:39 PM

What is the best way to drive in traffic in order to smooth out the flow and get to your destination quickly?

I drive in rush-hour traffic regularly and spend a lot of time thinking about exactly how the traffic works. I would like to know whether the way I drive is as helpful for everyone else as it is for me and/or if there is a "best practice" for driving in traffic.

From what I can see, there are two options. Let's assume there is only one lane.

(1) Occupy any space in front of you as soon as you can. This results in jerky driving as you accelerate, then brake, over and over.

(2) Maintain a relatively constant, but slower, speed by allowing more space in front of you; if the car brakes, you'll take up that empty space. Often employed by trucks. If done right, you won't have to stop often because the car in front will have started moving again by the time you reach them.

I started to do (2) because I drive a stick and braking/shifting is a pain in the rear. From that it became a fun contest to see if I could go an entire rush-hour session without coming to a full stop. It occurred to me that this could help the flow of traffic by making it smoother and keeping everyone moving.

But is that even right?

Is there one method that bugs other drivers more than the other?

posted by ramenopres to travel & transportation (21 answers total)

Option 2 costs you time on a multilane road because other drivers will cut in front of you. Obviously this is not the case for a single lane, but that situation isn't very interesting because your total travel time is going to be the same, regardless (you'll move at the average speed of the car in front of you). Option two will save fuel, though, as braking and accelerating repeatedly uses more than driving at a constant speed.

There are actually lots of studies and models for how traffic flows and why it backs up, which you mighty find interesting.
posted by tylerkaraszewski at 8:46 PM on April 27, 2012 [2 favorites]

Leave enough room in front of you for people to merge in front of you very comfortably, driving the same speed as whoever is in front of you, but always leaving enough space for more as each car comes in. You'll have a positive smoothing effect on the traffic in front of you because more people will merge earlier rather than waiting as long. This is especially true if there's a bad merge coming up. I've also found people around me get a little more mellow and take my example on occasion.

(There's a fellow who does some research showing how this works, but I can't find his website at the moment.)
posted by spbmp at 8:49 PM on April 27, 2012 [2 favorites]

Option 2 is actually smarter in the long run because it reduces your likelihood of getting in an accident by allowing room for the driver ahead of you to make a mistake. When the traffic clears up, feel free to head to the leftmost lane and to speed past as many people as possible.
posted by lotusmish at 8:50 PM on April 27, 2012

Yeah, No. 2 is the way to go; they actually finally did a study that showed conclusively how traffic jams work recently (believe it was on the blue) and the jerky start/stop constant braking and accelerating thing is a definite contributing factor. If everyone would just relax, traffic jams would happen less.
posted by limeonaire at 8:52 PM on April 27, 2012 [1 favorite]

Option 2. Constant speed is far, far better. It requires less energy (accel and deccel) and is much more predictable than any other form of driving, so it is better for the traffic volume as a whole.

The stop-start driving will only get you there sooner by the amount of distance between you and the car in front, but you'll royally screw the people behind you who have to take avoiding action of your unpredictable movements.
posted by Brockles at 8:56 PM on April 27, 2012 [1 favorite]

Answers from the blue
posted by Bonzai at 8:57 PM on April 27, 2012 [2 favorites]

I also drive stick and follow option 2. It's easier with a manual transmission, safer, and saves gas. Besides, option 1 is totally stressful - just roll down your windows, turn up the music, and chill on the gas and brake.

I pity those poor suckers on the freeway. Gas, brake, honk. Gas, brake, honk. Honk, honk, punch. Gas, gas gas!
posted by domnit at 9:07 PM on April 27, 2012

I do (2). People do cut in front, but they are also likely to cut back out again if a gap opens up in an adjacent lane, so lane switchers are a wash I think. If I'm in big tailback, I try and spot a few easily identifiable cars and trucks around me, and see how we all progress. It's usually pretty even, whatever anyone seems to do.

Plus, I think it's more relaxing.
posted by carter at 9:27 PM on April 27, 2012

This guy thinks the answer is (2).
posted by Orinda at 9:33 PM on April 27, 2012

Another reason #2 is better is that it reduces the chances of you getting rear-ended, and if you do get bumped there is usually less speed differential, and less chance of getting smacked into the car in front of you.
posted by fleacircus at 9:35 PM on April 27, 2012 [1 favorite]

My commute is about 9 miles. Over completely open roads, assuming no traffic whatsoever, it would take me roughly 15 minutes at 60 and 11 minutes at 70. So if you had far more favorable conditions than you would ever get in the real world, you're looking at saving maybe 4 minutes.

The speed differences between someone driving a smooth speed in traffic and someone frantically weaving and attempting to get ahead will be far, far less than an average of 10 mph. The person trying to weave in traffic is going to get there like... maybe 15 seconds earlier? Maybe a minute or two at absolute best? Utterly negligible amounts of time.

You can observe this on city streets too - accelerate and drive slower, and watch especially for the people that honk, swerve around you, or take off from the lights like rockets. Most of the time you'll coast up next to or immediately behind them at the next traffic light.

Day to day driving is not racecar driving in any way shape or form, and you can rarely if ever reach your destination faster by driving faster. Especially with a manual transmission, it's not worth the wear on your car or your emotions to try to get ahead in traffic.

The roads would be a lot safer if more people thought about this stuff.
posted by kavasa at 9:47 PM on April 27, 2012

Also, option 2 doesn't cost you time from "people cutting in front." There are lots of people "in front" of you on the freeway, what matters is your average velocity over the course of the trip, and if you've got several car lengths in front of you, you often don't need to slow down at all if someone temporarily pops into that space looking for an illusory advantage. I watch those people get ahead of me, then fall behind me, then get ahead of me over and over again sometimes.
posted by kavasa at 9:49 PM on April 27, 2012

In addition to practicing #2, here are three more tricks:

- Practice a strict 1:1 merger vs. mergee (if that's word!) at sticky merges, I INSIST on this via the way I maneuver my vehicle and with my horn. I think merging early defeats the purpose of this, YMMV.

Merges go really smooth when it's a 1 to 1 thing, as both lanes keep flowing.

- Find the lane that moves smoothest in heavy traffic, and stick to it until you can't.

On the 101 Fwy driving into Downtown LA from Hollywood, the farthest right lane is the fastest until Vermont Ave, after that, it is the farthest left lane until after the 110 interchange, which is what starts to back-up traffic in the farthest right hand lane until the interchange is over. Know your route! Similarly, in high traffic driving into Downtown LA from the south on the 5, it is the farthest right hand lane that moves fastest, even with all the cars entering and exiting the freeway... y'know, think like a cab driver.

- Don't text in traffic or surf the web on your smartphone. That never helps;)
posted by jbenben at 10:18 PM on April 27, 2012

(2) Not only saves you fuel, it also saves fuel in every car behind you.
posted by -harlequin- at 10:54 PM on April 27, 2012

This guy thinks the answer is (2).

He is also mefi's own biilb, who comments in the recent thread linked by Bonzai.
posted by LobsterMitten at 10:57 PM on April 27, 2012

Option 3!

Your Mileage May Vary (ha!), but I recently made an incredible discovery: Hitting the road 15 minutes earlier or later can make a huge difference!

My theory is that everybody is trying to get to there destination on the hour or the half hour, and when I aim for the quarter I'm sneaking into lulls in the rush.
posted by jander03 at 11:06 PM on April 27, 2012 [1 favorite]

Braess' Paradox tells us that it doesn't matter what you choose. Traffic on freeways is selfish and the flow will adapt to whatever option you choose without reducing the apparent density of traffic. This is why adding lanes doesn't reduce traffic, because people are selfish.
posted by rhizome at 11:39 PM on April 27, 2012 [1 favorite]

If you like traffic, you might be interested in reading this book.
posted by box at 5:03 AM on April 28, 2012

Option 3!

Your Mileage May Vary (ha!), but I recently made an incredible discovery: Hitting the road 15 minutes earlier or later can make a huge difference!

My theory is that everybody is trying to get to there destination on the hour or the half hour, and when I aim for the quarter I'm sneaking into lulls in the rush.

This is absolutely true in some cases. Before they rebuilt the highway I use, if I needed to be at work at 8:30, I could leave at 8 and get there just fine. If I needed to be there at 8, I needed to leave at 7. A half hour earlier doubled my commute.

Similarly, if I can walk out 10 minutes early and be on the road at 5, my commute home is a breeze. But if I have to walk out at 5 with everyone else, it is a nightmare. And I figured out that that strategy works, generally, for every 15 minute chunk of the clock.
posted by gjc at 6:47 AM on April 28, 2012 [3 favorites]

Similarly, if I can walk out 10 minutes early and be on the road at 5, my commute home is a breeze. But if I have to walk out at 5 with everyone else, it is a nightmare. And I figured out that that strategy works, generally, for every 15 minute chunk of the clock.

Guess what time fraction traffic engineers use to find out the time of the largest demand? 15 minutes as this adequately captures it and any longer misses it and makes it appear lower. Also the time is considered to be adequately captured if the two hours around it (meaning a total of 2 hours with the 15 minutes of peak demand being in the middle) and no other time needs to be measured. In most cases this occurs in the pm between 5 and 6:15 pm in major metro areas. The most cost effective way to break up traffic jams that occur every day is to try and convince/motivate major employers in the area to shift around schedules so that starting/quitting time is not right at 8 am or 5 pm. True story.
posted by bartonlong at 10:21 AM on April 28, 2012 [2 favorites]

In town, I make sure i don't leave big empty spaces when I'm at an intersection. I go through a lot of poorly designed intersections, and if someone leaves a gap, then some car doesn't get through the light. It mounts up and slows traffic. Otherwise I try to drive smoothly.
posted by theora55 at 12:06 PM on April 29, 2012