When you slow coast in stop and go traffic aren't you saving more gas than just your own?

[burritos]

Last friday I was in some hellacious stop and go traffic here in Los Angeles as I ventured back and forth to disneyland through rush hour twice. Over the 3 hours of driving I was able to achieve 59 mpg which is the best I'd ever done over long periods of driving. I believe I was able to achieve this because my driving strategy was to brake as little as possible. At times, the traffic in front of me would sometimes get to 20 car lengths. Knowing I would just have to brake, I avoided speeding up to close that space. This is not the typical behavior of most drivers in stop and go traffic. Typically, if you see space ahead, you speed up till you can read the bumper stickers of the car ahead of you.

This is nothing new to the knowledgeable prius driver. I wondered if the people behind me was annoyed and the people behind those people and so forth. They must have noticed the huge gaps that came and went in front of me. But did they also notice that they too never had to brake much, same with the people behind them and so forth? It might have been slow, but they were moving in a constant more efficient speed. Not only did I maximize my gas efficiency, but I probably maximized a dozen cars' efficiencies behind me, if not more. Sure a few cars cut around me and quickly found themselves in the same inefficient stop and go rut and no further ahead to boot. But most people in my rear view mirror stayed behind me for a large portion of the drive. Did they do this because passing me just wasn't worth the effort or did they appreciate the sanity of this slow coasting?

Needless to say, I was worried that this slow coasting was going to annoy many people. I would never do it unless it was stop and go traffic. But upon reflection, annoyance is inevitable in this kind of traffic so why not have my car and the dozens of cars behind me minimize its gas consumption in this parking lot that we call the LA freeways?

[BartVB]

20 cars sounds like a lot, normally I keep those gaps limited to approx 10 cars (depending on circumstances). But yes, you've probably saved some more gas and if more people would do this there would be less traffic.

Most traffic (at least here in The Netherlands) is caused by someone braking, the guy behind that braking a little bit harder, next one even harder, etc, etc until someone has to come to a full stop. Normally this starts with someone just barely touching their braking pedal and the guy behind it not keeping enough distance :\

If everyone would just keep their distance and would avoid this stop and go stuff everything would go much, much more smoother. But alas this requires everyone to take it a little bit 'slower' for the common good. Of course there are always people who try to take advantage of that by filling up the gaps that are created by this and thereby ruining most of the benefits of keeping enough distance and coasting at a steady speed.

[San_Carlos_Jeff]

It would be an interesting simulation to model that and see what is more efficient (it's probably already been done somewhere).

My intuition tells me that if everyone drove that way it would be a big mess. Imagine the traffic you were in and if everyone kept such a large space between each other the jam would have been 10 to 20 times as long spreading into more freeways and causing more onramps to back up. When I'm in traffic like that I try to keep the stopping and starting as smooth as possible, while also keeping the spacing as tight as the speeds dictate.

[KK6PD]

Originally Posted by burritos

Last friday I was in some hellacious stop and go traffic here in Los Angeles as I ventured back and forth to disneyland through rush hour twice. Over the 3 hours of driving I was able to achieve 59 mpg which is the best I'd ever done over long periods of driving. I believe I was able to achieve this because my driving strategy was to brake as little as possible. At times, the traffic in front of me would sometimes get to 20 car lengths. Knowing I would just have to brake, I avoided speeding up to close that space. This is not the typical behavior of most drivers in stop and go traffic.

I can verify your results, because I did exactly the same thing a couple of months ago when I drove south on the "5" past Disneyech and got to my destination. I had the BEST MPG ever!!! If I could only acheive those results everyday!!

As far as the folk behind you... to quote the Gumball Rally, "What's behind you is not important"

[BartVB]

Originally Posted by San_Carlos_Jeff

Imagine the traffic you were in and if everyone kept such a large space between each other the jam would have been 10 to 20 times as long spreading into more freeways and causing more onramps to back up. When I'm in traffic like that I try to keep the stopping and starting as smooth as possible, while also keeping the spacing as tight as the speeds dictate.

I think that's also what burritos is suggesting. He's acting as a buffer for the stop and go driving by keeping his distance from the tail of the traffic jam when everyone is in 'go' mode. When the traffic is in stop mode again the amount of space between him and the cars in front of him will decrease. The people behind him can keep a normal distance for the (constant) speed from him, no need to keep 10 or 20 car lengths between all cars

BTW a lot of research has been done when it comes to traffic jams:

trafficwaves.org/trafexp.html

(can't post URLs yet)

Bottomline; trying to keep a constant speed really does improve throughput of a highway (and an added benefit is that it reduces fuel requirements, especially for non-hybrid cars).

[nooaah]

If you were coasting over 7 mph and didn't mind upsetting the people behind you then that was a good strategy, indeed.

[BartVB]

If you're not creating huge gaps I don't think people will be annoyed, most of them will be glad you're evening out some of the stop & go pattern that makes driving in traffic rather tiresome. I've applied the above technique numerous times in my 'normal' car and it really didn't seem to upset the people behind me

[patsparks]

That is how I drive in stop go traffic regardless of what I'm driving.

[nooaah]

Yup, I generally try to stay in motion as much as possible. I'll never understand the people who zip and then slam the brakes over and over.

[Frayadjacent]

You can definitely positively affect the flow of traffic behind you by not varying your speed as much as the people in front of you.

You can also piss a lot of people off if you don't keep up with traffic!

Best advice - worry about yourself. Let other people worry about how much gas they burn.