Hill Hold Function

[brianman]

Automatic, or manual? Can't remember rolling back in any of my automatic vehicles.

Happens in Seattle downtown.

 

[ckessel]

So what's your technique for a driving an automatic car in a steep road with stop and go traffic? As soon as you let go of the brakes your car will reverse and hit the car behind you. If you try to quickly move your foot to the "gas" pedal, you will more than likely over throttle and hit the car in front of you.

You simply learn to be quick whether you're in an automatic or manual. In an automatic you'd have to be on one hell of a hill to defeat the creep. In a manual, you learn to feather the clutch as you switch over so there's no "lurch" forward. If you have a hand brake, you can use that too.

I'll lay money that every driver's class that exists will tell you to only use your right foot for brake and gas, never use both.

 

[ckessel]

Try driving the hills of San Fran -- they're steep enough to overpower any ICE's creep.

My wife grew up in that area and says that while it's not unheard of (foot on each pedal) it'd be very, very rare.

 

[ckessel]

For what it's worth, if you look up "left foot braking" it's apparently common in racing, but highly discouraged in non-racing. Here's an example:
DriveSmartBC | Left Foot Braking

I am occasionally asked about using the left foot for braking instead of the right foot. The usual justification given for this is that the brakes may be applied more quickly because the left foot is ready while the right foot is busy with the accelerator pedal. While there are different schools of thought on whether this is appropriate for highway driving it may not be a good idea for the average driver.

An important job for your left foot and the leg attached to it is to press against the raised portion on the left side of the driver's foot well. This action forces the driver into the seat and anchors the body leaving the arms free to steer with during lateral acceleration and heavy braking. Staying in complete control means not hanging on to the steering wheel in order to keep your body in position.

If you get lazy and ride the brake with your left foot enough to light the brake lights will confuse the driver behind you. Are you stopping or not? Confusion like this will lead to an increased chance of being hit from behind and contributes to excessive brake wear and poor fuel economy.

In the event of a collision, the resulting pressure on both the brake and the accelerator will reduce the effectiveness of the brakes at a time when they are needed.

Finally, check with your driving examiner. Left foot braking during a road test may not be acceptable in all circumstances.

 

[stopcrazypp]

My wife grew up in that area and says that while it's not unheard of (foot on each pedal) it'd be very, very rare.

Depends on what area in SF. If you are near the Russian Hill and Nob Hill area, then you regularly come up on hills that will roll any car backwards. If you are quick enough then you will still have a little bit of roll (it's not non-existent). Two feet allows you to not have any rollback and gives you better control.

I agree every driving instructor will tell you to use one foot in general, but my instructor did give me a tip that you may use two if dealing with steep hills in SF.

 

[CyberDutchie]

So what's your technique for a driving an automatic car in a steep road with stop and go traffic? As soon as you let go of the brakes your car will reverse and hit the car behind you. If you try to quickly move your foot to the "gas" pedal, you will more than likely over throttle and hit the car in front of you.

My Kia Optima has a feature called Hill Assist Control (HAC). It offers an added measure of security when moving from a stop on a steep hill by preventing the vehicle rolling backward. It functions by gently applying the brakes for two seconds while you move your foot from the brake pedal to the accelerator.

Sounds like something Tesla could easily implement in the Model S.

 

[SCW-Greg]

You simply learn to be quick whether you're in an automatic or manual. In an automatic you'd have to be on one hell of a hill to defeat the creep. In a manual, you learn to feather the clutch as you switch over so there's no "lurch" forward. If you have a hand brake, you can use that too.

I'll lay money that every driver's class that exists will tell you to only use your right foot for brake and gas, never use both.

Has anyone heard of "hill holder" or the various other names that most all automatic cars today have? Designed to automatically stop the car from rolling backward, once you first apply the brakes at a stop light. Then you can take your foot off the brake and your car should not roll backward, on any hill.

 

[MikeK]

The top of Nob Hill always, always smells like burnt clutch.

Although my right foot is pretty quick (lots of practice when I used to drive a stick), I sometimes use the hand brake in the RAV4-EV to prevent any rollback on a really steep hill like that. Depends on the situation, what's behind, etc. Sometimes, you park on one of these steep slopes, and somebody parks behind you, so there's very little margin for rollback when it comes time to leave.

I hope the S will have a "hill hold" feature since it has no hand brake. I think it's been discussed as being under consideration.

 

[Frank Herfjord]

Using some throttle while braking shifts the brake balance and applies more lock to the rear differential. This helps keep the car stable when trailbreaking into a corner at high speed.

There is no reason to do it in regular driving and you would normally have to adjust everything from rebound damping to brake bias in a race car to benefit from the technique. And then there's the concern of overheating brakes.

 

[NigelM]

Although I've never felt the need for a hill hold function (and now we live in Florida! FL=flat) I was surprised to find that a Nissan Sentra I rented in Vancouver had this function. Worked great not needing to use my feet at all to hold the car stationery uphill in the mountains of B.C. Odd though that downhill the car rolled forwards?

 

[jerry33]

Although I've never felt the need for a hill hold function (and now we live in Florida! FL=flat) I was surprised to find that a Nissan Sentra I rented in Vancouver had this function. Worked great not needing to use my feet at all to hold the car stationery uphill in the mountains of B.C. Odd though that downhill the car rolled forwards?

Wrong tires.:smile: I once had a set of Yokohama A001-R tires when I lived in Vancouver and you had to actively press on the accelerator to roll down Simon Frazer University hill. However, they were the best rain tires that I've ever used.

 

[W8MM]

Depends on what area in SF. If you are near the Russian Hill and Nob Hill area, then you regularly come up on hills that will roll any car backwards. If you are quick enough then you will still have a little bit of roll (it's not non-existent). Two feet allows you to not have any rollback and gives you better control.

I agree every driving instructor will tell you to use one foot in general, but my instructor did give me a tip that you may use two if dealing with steep hills in SF.

We have plenty of hills in Cincinnati and it's rare that I have any trouble at all just using my right foot. San Francisco hills, on the other hand, were quite a learning experience on my first try. I ended up using a heel-and-toe technique after experimenting with left foot braking. My left foot just wasn't talented enough to gently apply the brake -- it's used to mashing the clutch.

Porsche cars with their PDK dual-clutch/shaft "automatic" transmissions have a pretty good hill-hold feature that works out its own transitions between stopping and going. I it find very workable. The computer decides how much g-force is sensed while parked at zero MPH and may chose to apply the brakes on its own. Once the "hold" icon lights up on the dash, I can remove my foot from all the pedals and the car remains in place. All I have to do to start back up is put enough pressure on the gas pedal to overcome the grade and off we go. Very nice.

 

[EVNow]

Happens in Seattle downtown.

Yes - I always dread having to stop at the traffic signal going up on a steep hill (and many of them in most roads) i.e. I used to until I started using the hill hold in Leaf.

 

[bob_p]

My Lexus LS has a "Brake Hold" feature that automatically holds the brake when the car comes to a stop. Even though I'm in an area that's very flat - I still use that feature all of the time - so that once I'm stopped at an intersection - I don't have to keep my foot on the brake pedal - instead - I can be ready to hit the accelerator as soon as the light turns green.

I'm assuming the Model S is "fly by wire" - so adding features like Brake Hold or automatic parking (which is also on my LS) may be possible through a software upgrade.

Some cars have a camera watching the driver's eyes - to verify the driver is actually watching the road - and if the driver is distracted (or falling asleep) - the car will detect it and take action - features like this (or adaptive cruise control with laser or radar) need some additional hardware in the car on top of new software needed to implement the features.

Hopefully Tesla will continue adding this refinements to the Model S - and bring it closer to competing head-on with the features available in other cars in this price range.

 

[Incredulocious]

How does the Hill Hold feature work in the Leaf?
I've got a Leaf and this is the first I've heard of this feature in this car.

My Prius has the feature though and it works fine.

I don't see any evidence of automatic hill start / hill hold on the LEAF. Searched the web and my pdf copy of my 2011 user's manual. They do describe manually using the parking brake to hill start and they do warn against using the motor to hold your position on the hill (as opposed to the brakes). I have not yet found myself stopped on a severe uphill to see if the parking brake is necessary to do a smooth hill start.

 

[brianoflondon]

John Voelker at Green Car Reports has had confirmation from Tesla that there is no Hill Hold.

Just for reference this is from the Instruction Manual of my Renault Fluence ZE. The feature works very nicely and is damn near essential in Jerusalem:

Hill start assistance
This function assists the driver when starting on hills. It prevents the vehicle from rolling backwards, depending on the slope, by automatically applying the brakes when the driver lifts his/her foot off the brake pedal to depress the ac- celerator pedal.
System operation
It only operates when the gear lever is in a position other than neutral (other than N or P) and the vehicle is completely stationary (brake pedal depressed).
The system holds the vehicle for ap- proximately 2 seconds. The brakes are then gradually released (the vehicle will move according to the slope).

The hill start assistance system cannot completely prevent the vehicle from rolling backwards in all sit-
uations (extremely steep gradients, etc.).
In all cases, the driver may depress the brake pedal to prevent the vehi- cle from rolling backwards.
The hill start assistance function should not be used for prolonged stops: use the brake pedal.
This function is not designed to im- mobilise the vehicle permanently.
If necessary, use the brake pedal to stop the vehicle.
The driver must remain particularly vigilant when driving on slippery or low-grip surfaces and/or on hills.
Risk of serious injury.

 

[brianman]

John Voelker at Green Car Reports has had confirmation from Tesla that there is no Hill Hold.

Not yet. But there is some word of it coming...

Sign into My Tesla | Tesla Motors

Then to top it off got to chat with George B for about 30 minutes on lots of topics. My wife and I are really impressed with George. He is genuine and spoke very clearly about several issues. I asked him about the hill hold mode (not present yet). He described how the engineers are currently prototyping this function with various combinations of motor hold and park brake. They are not yet satisfied with the smoothness upon release so are not going to release that until its perfected. This is EXACTLY the sort of answer I was looking for from a senior executive.

 

[grisnjam]

Originally Posted by pilotSteve
Then to top it off got to chat with George B for about 30 minutes on lots of topics. My wife and I are really impressed with George. He is genuine and spoke very clearly about several issues. I asked him about the hill hold mode (not present yet). He described how the engineers are currently prototyping this function with various combinations of motor hold and park brake. They are not yet satisfied with the smoothness upon release so are not going to release that until its perfected. This is EXACTLY the sort of answer I was looking for from a senior executive.

Awesome news.

 

[arnolddeleon]

I don't see any evidence of automatic hill start / hill hold on the LEAF. Searched the web and my pdf copy of my 2011 user's manual. They do describe manually using the parking brake to hill start and they do warn against using the motor to hold your position on the hill (as opposed to the brakes). I have not yet found myself stopped on a severe uphill to see if the parking brake is necessary to do a smooth hill start.

I don't know of an automatic hill hold/start that is enabled automatically. The parking brake can be used for hill holding by simply activating when stopped. When it is time to go just press the accelerator and the parking brake will release automatically (provided you have your seat belt on). In a fashion this automatic I suppose since you don't have coordinate releasing the brake.

arnold

 

[grisnjam]

I don't know of an automatic hill hold/start that is enabled automatically. The parking brake can be used for hill holding by simply activating when stopped. When it is time to go just press the accelerator and the parking brake will release automatically (provided you have your seat belt on). In a fashion this automatic I suppose since you don't have coordinate releasing the brake.

arnold

The hill hold in my Audi A3 is automatic. It has the DSG transmission and when stopped on a hill will apply just enough creep via the clutch to keep the car in place for a few seconds at which point it lets you roll backward to preserve the clutch. No brakes involoved.