At what speed do you start braking?

[NoD~]

I've been hypermiling for, what, a year now? I've always wanted to ask this, but always forgot to do so when I hit the forum... until now!

We all have to come to a stop eventually. I know there are a few hardcore ecomodders that don't touch the brakes pretty much at all, but curious where the average lands.

For me, I'm usually between 10-15MPH. Usually perfect to bump the clutch and restart the car, as I usually EOC.

Post up, vote, whatever suites ya. Just curious

[Frank Lee]

At what speed do you start braking?

When I see the deer's eyes.

[ksa8907]

in ideal conditions? just under 20mph. i can downshift my auto and use dfco but the injectors come on between 30-38 in 3rd gear, and below 20 in 2nd.

[Xist]

I wish that I knew how to time exit ramps.

[UFO]

It completely depends on how much excess momentum I have to scrub. I basically use my brakes at the point I can comfortably stop. If I can completely plan my stop, I engine brake to 10mph where fuel consumption rises above idle fuel consumption, I use DFCO to minimize fuel since I cannot turn off my engine.

[LeanBurn]

When DFCO kicks out so #2.

[mikeyjd]

Almost never unless I'm in town and have to. Stop sign=5-10mph

[user removed]

Too many variables to state any precise speed. I may brake early to be moving at best speed when a light changes. I have to deal with a lot of lights, some stretches are several miles with no lights, then a light every .3 mile or even less.

Light timing demands very specific speeds for me, even two MPH can mean the difference between missing 40 of 46 and hitting 30% of the same 46 in a 40 mile drive.

That same timing forces you to risk catching a tripped light at exactly the wrong time. Pure stupiditywhen 40 cars have to slam on brakes so one car can make a left turn. I would be the traffic engineers here aren't even potty trained.

Other drivers are also a major factor. In most cases I will try hard to not interfere with other drivers. The exception is those who stay planted a car length behind you when they only need to move to the fast lane and pass, and they have no obstructions to do that. In that case I will just go in neutral and coast until they get the message, and I have seen that take me from 45-50 to under 20 MPH before the idiot gets the idea.

In the rare instance where I have,

1. no other traffic around
2. no light timing to worry about
3. no time schedule to keep

I would probably coast down to under 10 MPH or to a complete stop, but those are very rare times when there are no outside influences.

regards
Mech

[Diesel_Dave]

It's hard to pick just one value--it depends on the circumstances. I can think of primarily 3 scenarios.

1) Best case scenario: not at all
This is my goal for any red lights & turns. Ideally, I EOC down to the speed where I can either make the light on green or make the turn. This, however, isn't really an option for stop signs where one must come to a complete stop

2) "Near-ideal" stop sign scenario: 1-5 mph
This is what I consider my ideal scenario for stop signs. I EOC down to about 5 mph, which leaves me just enough energy to consistantly bump start. It also extracts enough energy so that my speed is near-zero and the brakes just barely need touched. This being said, this obviously isn't an option when someone's following you. It also helps a lot to have knowledge of the route to know how to to consistantly glide down to just the right speed.

3) Non-ideal scenario: whatever you have to do
When you're in traffic, of if you mis-time something, then you gotta fo what you gotta do. I would include in this what I call "scrubs"--when I've mis-timed a light it's sometimes beneficial to use the brakes some early on in order to prevent having to come to a complete stop later. The goal tis to preserve as much kinetic energy as possible.

Something else that should be noted is that the "ideal" speed is dependent upon whether one is engine-off or engine-on coasting. If one is engine-off coasting then slower is always better--at least down to the point that you can still bump start. When engine-on coasting there's a break-even speed where the (idle fuel rate)/(vehicle speed) = (target mileage). If vehicle speed decreases further then you start hurting your mileage.

An DFCO is just silly anyway compared to EOC.

[XYZ]

Originally Posted by Diesel_Dave

It's hard to pick just one value--it depends on the circumstances.

The poll is meaningless for that reason. Your description is well said. It varies, according to circumstances.