Cruise Control minimum speed

Cruise Control minimum speed

The minimum speed for the cruise control on my Tesla Roadster is 30 mph. I prefer for Model S this minimum speed will to be lower. Using Cruise Control, even at low speeds, makes driving safer. It is better to look outside the car and scan for what is going on on the road with your right foot ready to brake instead of concentrating on your speedometer and your right foot on the accelerator to avoid a ticket.

BYT | 2012年9月13日

I agree with you Paul, and if we can set cruise control as low as say 3 MPH, we wouldn't even need creep as an option, we can set the speed ourselves. Wonder how fast creep would be in relation to an ICE? My guess was about 3 MPH.

Norbert.Vienna | 2012年9月13日

I drive a Mercedes S and the cruise control together with a distace radar is 0 mph
I prefer that kind. It is very convinient especially in a stop and go situation. The car stops automatically and as soon as you touch the cruise control stick it starts again to go to the set speed

BYT | 2012年9月13日

@Norbert.Vienna, I like that even more... :)

Michael23 | 2012年9月13日

Or add laser guided like my 03 Infiniti which will slow all the way down and speed back up for you automatically.

Volker.Berlin | 2012年9月13日

Discussion about adaptive cruise control:

In short: Like other driver assistant features, adaptive cruise control is on the wish list for the Model S and will likely be available at some point. At this point, it is more important to get version 1.0 out the door, and more electronic assistants would have delayed availability.

Timo | 2012年9月13日

I think they will add a fully automated robot driver at some point not far into future. Google already has successful robot driver, and because that is basically just an extension of computer tech knowing how fast that goes forward it doesn't take long to have that in any new car. Ten years max to perfect the tech, and another ten max to get it as standard equipment to all cars.

It just takes some sensors not common in normal cars. Cameras, radar, maybe lidar. More passive than active, heat cameras etc.

Keeping in mind that this would still be drivers car, consider that robot driver as silent co-pilot that you can activate when you feel you need it.

Sudre_ | 2012年9月13日

Am I wrong that the "New features" part of the service plan should mean that if I have the service plan I will get adaptive cruise when it is available? along with proximity detectors.....

Volker.Berlin | 2012年9月13日

Sudre_, it depends.

If a feature can be enabled merely by software, I understand that everybody (not only those with a service plan) will get the new feature, sooner or later, and for free. Examples are configurable creep, or a chime on speed limit.

Other features, including adaptive cruise control, may need additional hardware (sensors, in particular). It may or may not be possible to retrofit that hardware to cars that are already on the road, and if it is possible, it is likely a paid option (and equally likely, when it becomes available, it will be a paid option in new cars for new customers as well).

Mark E | 2012年9月14日

Robotic driver control is my idea of hell. I love driving. If you hate driving get a taxi. :)

Sudre_ | 2012年9月14日

They already said the wiring is there for certain features. I am hoping that it includes most all updates to the car so I am not getting the early adopter punishment if I get the service plan. I will be asking that question before getting the service plan.

BYT | 2012年9月14日

@Mark E, I hear you, but sometimes you need to answer a call or something comes up, an autopilot would be awesome in order to avoid the Hands Free Ticket I have already received (and paid $460 on by the way). It wouldn't even allow me to pay the fine online, I had to go to the Courthouse, wait in a ridiculous line and then find out that they don't accept VISA!?!?

Mark E | 2012年9月14日

BYT: if you need to answer a call then you need a full hands free kit in the car. If its a call that demands a lot of attention pull over and park. I don't want to be killed because someone is driving a 2 ton projectile at 60 mph and not concentrating on the road and traffic around them.

I've had hands free kits in my cars since getting my first mobile phone in 1991. With Bluetooth kits being so cheap these days there is no excuse for not having one.

As a motorcyclist as well as a car enthusiast I'm amazed at how easy it is to spot the drivers who aren't using hands free, just by the jerking corrections being made as they drive. $460 is cheap compared to the guilt you'd have if you killed someone while distracted.

Here in Australia you also face prison if your negligence results in a serious accident.

BYT | 2012年9月14日

@Mark E, I agree that there are dangerous drivers on the road that can't talk and drive (even with that damn headset in their ear). In my case, I was sitting at a red light that takes 2 minutes to change before entering a private parking lot. I don't text and drive, I don't apply makeup at 55MPH while slowly swerving into me in the fast lane and pressing me into the cement wall divider, I don't drive oblivious to those around me. On that note, I don't agree that stupid laws fix anything because I still see people with phones to their ears all the time and it frankly seems to do nothing to the true offenders.

Please bring a user enable/disable-able auto-pilot! :)

Mark E | 2012年9月14日

@BYT: I don't think that the hands free requirement is a 'stupid law' at all. If the penalty for driving with a phone held to your ear was immediate disqualification then maybe you wouldn't see as many people ignoring it.

Driver distraction and inattention are two of the biggest contributors to accidents - above speed and about at the same level as fatigue.

Will 'autopilot' read the conditions of the road in front of you and recognise a minivan with kids getting out or some other 'early warning', to immediately slow down and take care the way a responsible driver will? My guess is that it will continue at speed until it sees an obstacle, then it will take emergency avoidance actions.

At best it will mean that people who aren't interested in driving will hand over to it. At worst it has the potential to lead even more people to being even more lazy when driving.

Brian H | 2012年9月14日

Do hands think and see? Hands-free achieves nothing.

Mark E | 2012年9月14日

@Brian H: When people are using a hand held device in a car they spend a lot of time looking at it or not having their hands on the controls. I have witnessed this.

Further, when they are talking on the phone holding it to one ear for some reason there is a propensity to not look and check blind spots etc. I have witnessed this.

When the phone is in a cradle you don't need to fumble around to find it and answer it.

Of course, if the conversation that you are having requires a lot of thought then you should not have it while driving.

Hands-free does make a massive difference.

Robert22 | 2012年9月14日

Have to agree with Brian on this one. There is no safety advantage in hands-free (Bluetooth) vs. physical handset. It may seem that way for the reasons mentioned by Mark, but numerous studies clearly show the human brain was never designed for multitasking. Performance in all areas tested decreases as additional tasks are added. These days when I hear someone proudly proclaim they are a "multitasker", I wonder what task they're performing suboptimally.

If people are serious about reducing accident rates, phones could easily be temporarily auto-disabled when their GPS signal indicated speed above X mph. I doubt any politician would want to end his career advocating for disabling legislation.

Timo | 2012年9月15日

@Mark E, robot driver as it is done in Demolition Man. Flip a switch and you are in control, but you can give control to car as well.

Full-time robot driver would be bad IMO, it would just take fun out of driving. Maybe as emergency assistant (computers react couple of thousand times faster than humans), but nothing more while you are driving.

Why settle to one when you can get both?

Brian H, hands free achieves something. No huge difference but it is not negligible. For one you have both of your hands free to act which is important (muscle memory), second the things Mark E mentions, people tend to look at the phone time to time, and in very worst case you drop it and start to dig it out from the floor while driving (I have seen this). When you hold it at your ear it becomes physical distraction instead of just mental distraction.

TRex | 2012年9月15日

If hands-free is dangerous, why are passengers allowed?

Timo | 2012年9月15日

Passenger is a bit different than phone, because passengers are in same situation as driver and usually don't keep babbling about something unimportant when car is are situation which requires drivers full attention. If passengers would keep on talking to driver while he tries to avoid head-on collision with drunken driver there would be something to keep them shut down.

I have seen signs in public transportation that prohibit talking with the driver probably just because that.

Timo | 2012年9月15日

is are / is at. I have started to think my FF auto-corrects my texts, there have been some very weird typos recently in my texts (actual words, but in strange places).

jerry3 | 2012年9月15日

Mark -- Robotic driver control is my idea of hell. I love driving.

Sometimes I want to drive but sometimes I want to get there without being bothered or I want to look at the scenery on the way there or take a nap rather than the road. Taxis work in places like New York and Tokyo because you never go very far. They are ruinously expensive elsewhere, and I don't want to spend hours with some stranger--even if I could afford it. An auto-pilot would be a great idea--and I suspect it would be a great idea for about 90% of the folks out there.

Having said that I never use cruise control, but that's because cruise control kills mpg.

kalikgod | 2012年9月15日

I love to drive, but I would love to have a real auto-polit for some situations. I have a long drive to work with some heavy slow and go sections where I get no driving enjoyment. Passing off to an auto-pilot while I get a head start on morning email would be worth a $10k option for me.

The one autopilot feature that would be even better is auto-valet. I am getting sick of watching valets fumble getting my LEAF in drive. I would rather not have them touch my car and it go park/charge itself.

jerry3 | 2012年9月15日


I haven't even seen a place where there was valet parking since the early seventies. However, it's scary when the "Prius certified technician" doesn't know how to start the car.

jbunn | 2012年9月16日

I was just driving over a mountain pass tonight. I allways drive with cruise control. Who needs a speeding ticket, right? Only problem is downhill where cruise would need to break or downshift on an ice. And so I end up going way over the limit, and someday im gonna get it if im not carefull. Was just thinking that tesla cruse control probably maintains set speed, even on downhill stretches. No reason why it shouldnt be able to have precise control, regardless of grade.

jkirkebo | 2012年9月17日

Yep, it should. The Leaf does, to an extent. The Leaf can only use as much regen in cruise as is available on the accelerator pedal. Thus it can regen more in eco than in D but the full 30kW amount is not available for CC to use since one has to push the brake pedal to get full regen.

This should not be an issue with the Model S since it has all the regen on the accelerator (yay!).

EdG | 2012年9月17日

But if the hill's slope goes past some angle, the amount of regen needed to keep it at a constant speed (set by cruise control) may be too much for the system. In that case you'd have to step on the brakes.

jkirkebo | 2012年9月17日

For a Model S with 60kW regen that angle would be _steep_. So steep that you could not keep the same speed going up using 60kW.

Volker.Berlin | 2012年9月17日

Tesla wouldn't be the first to have the cruise control actually engage brakes to maintain the preset speed.

jkirkebo | 2012年9月17日

I wouldn't want it to do that. An increase in speed is more energy efficient.

jerry3 | 2012年9月17日

Using cruise control is never efficient.

BYT | 2012年9月17日

Lowers fatigue when driving for an extended period however

toto_48313 | 2012年9月17日

@ Jerry,

every one doesn't have the same point of view:

Sammy on September 15, 2012 at 3:16 pm said:

Which is more efficient in controlling the power consumption the cruise control or yourself, and is your answer different depending on the terrain? I guess there was not time to stop at the BSF for a flying mile top speed test.

Reply ↓

teslamodelsxc on September 15, 2012 at 4:55 pm said:

Cruise control is absolutely the most efficient period. I looked for a charging station at the BSF but no luck. I guess all of the EVs that set speed records bring their own.

jbunn | 2012年9月17日

Acceleration is the enemy. That includes speeding up, slowing down, or changing direction. If cruse maintains constant speed, thereby minimizing acceleration better than I can as a human, why whould it never be more efficient? I assume exactly the opposite.

Timo | 2012年9月18日

In hilly terrain if you coast down and use that gained energy to climb up the next hill you use less energy than cruise control steady speed, even with regen braking. Situations vary.

Teoatawki | 2012年9月18日

I've never had a car where cruise control did anything other than maintain a minimum speed. When you go downhill, it just lets you keep going faster. In rolling hills you hit the next upgrade with the excess speed you just picked up.

I usually set my cruise control at a speed I want to stay above, then drive normally. So, if I slow down because of a hill or tired foot or calculating Pi in my head, the car reminds me.

Brian H | 2012年9月18日

Surely, having calculated П once, you don't need to do it again?!?

EdG | 2012年9月18日

@Teoatawki: In all cars I've driven, the cruise control gives the car enough gas to get to the set speed. If the car, going downhill, speeds up, then the controller reduces the gas. If the Model S does that, regen will kick in on the downhill.

So if there's any variation in terrain or wind that would push the car off the set speed, regen and more power will be used alternately to maintain the set speed. We don't know if Tesla is using a more sophisticated algorithm, but, if not, it's a good bet that keeping the speed within a small range centered on the desired speed, using acceleration and coasting, would use less power than simple cruise control.

EdG | 2012年9月18日

Correction: would use less energy

Theresa | 2012年9月18日

My experience with my Roadster has shown that I get better range with my foot than with the cruise for exactly the reason that are being made here. On downhills the regen kicks in and that is not nearly as efficient as letting the car roll faster. Now you have to make sure that you either don't get too far above the speed limit for obvious reasons but most hills I am on don't get me too far away from the speed limit.

Also I have found that if I can keep the kw/m usage even and let my speed vary I get considerably better range. In fact I have shown that I can surpass the rated range if I never go above 55 mph on flat and uphills. I have found that using a simple formula (speed in mph divided by 5) and use that number as a guide to use for kw/m it is easy to get rated range on a long trip. So for a 55 mph speed if I keep the usage to 11 kw/m I will be sure to get full range. This is very simplistic but works well for me. Ideal range uses slightly more than that number (more like 11.6 or so) but it is hard to control the usage closer than that.

Volker.Berlin | 2012年9月18日

EdG, Theresa, that's how Mercedes claims to achieve fuel savings of around three percent with their "Predictive Powertrain Control":

Based on GPS and map data, the system allows to slow down when going uphill and coasts downhill (all within preset ranges), using the momentum from going downhill as a head start on the next uphill section.

It think cruise control that sets a range rather than a fixed speed is due for one of those praised "New Features" software updates! :-)

Volker.Berlin | 2012年9月18日

Sorry, try this link for Predictive Powertrain Control

Volker.Berlin | 2012年9月18日

Here's an update on cruise control as currently implemented in the Model S:

Volker.Berlin | 2012年9月18日

"One comment on the cruise, which is probably intentional for every day driving, but slightly counterproductive when you’re trying to conserve battery. When you change speed, the car applies liberal amounts of accelerator or decel to get to the desired speed almost immediately, and then jumps back to the steady state condition. And with 416HP and 443lb ft of torque on tap, it could be considered overkill, or at least not how Grandpa (or Grandma) would drive."

This is something I also observed in ICE rental cars. There are significant differences between the usual suspects (Audi, BMW, MB) in how smoothly or abruptly the car tracks changes in the cruise setting. I just recently had a brand new A6 that jumped to any new cruise setting full force, even if only a few mph faster or slower, in a way that required an excuse to my passengers. In my memory, the last time I was driving an E class, tracking the cruise control was much smoother and barely noticeable when going only a few mph up or down (to match the car in front). As you may have guessed already, I very much prefer the latter implementation. For now I assume that Tesla will have an update for that at some point. :-)

On a related but different note, MB's two-stepped cruise control stalk that is also used in the Model S is one of the nicest interfaces for cruise control I've seen so far. Very easy to adjust without a lot of fuzz. The A6 I mentioned above tried to mimic that with a similar stalk, but failed IMO. I'm glad to learn that in the Model S it seems to work as it should!

Rod and Barbara | 2012年9月18日

I haven't seen the original question posed in this thread answered. The minimum setting for cruise control in the S is 20 MPH.

Kipernicus | 2012年9月18日

Perhaps another way is to have 3 parameters to set - max and min speed and a target energy use. If you know that 340 watts gives you 62 mph on flat ground then set that as the target energy use.

If you are going up hill (or facing a headwind) the 340w target means you will slow down, but only to the min speed.

If you are going down hill 340w means you will go faster, up to max speed and then wattage would reduce or even regen would kick in.

Much more complex than can be set with a stalk, but then we have the touchscreen for input.

dondennis | 2012年9月18日

Rod and Barbara - thanks for providing an answer to the original question!

Ohms.Law | 2012年9月18日

Ha! Thank you Rod and Barbara. Sometimes things get a little off point. Just a little.

Alex K | 2012年9月18日

@Kipernicus | SEPTEMBER 18, 2012: Perhaps another way is to have 3 parameters to set - max and min speed and a target energy use. If you know that 340 watts gives you 62 mph on flat ground then set that as the target energy use.

I like this and I was thinking about something on the same lines: Set the cruise control and when going up a hill the car will drop down a preset amount of mph depending on the hill angle. When going down a hill, the cruise control will speed up depending on the hill angle. So for example, setting the cruise control at 55mph and having a -3/+3 mph hill differential, the car would slow to 52mph up a hill and speed up to 58mph down a hill. These parameters could obviously be settable.

I'm sure there are many variations on this and using "target energy use" would add another dimension to equation. Target energy use could also be something that is pre-derived using the chart at . Target energy use could also be automatically set when cruise control is engaged using the current energy use.

Hopefully something on these lines is added in a future software update.

jerry3 | 2012年9月19日

jbunn -- Acceleration is the enemy. That includes speeding up, slowing down, or changing direction. If cruse maintains constant speed, thereby minimizing acceleration better than I can as a human, why whould it never be more efficient? I assume exactly the opposite.

You are correct that acceleration is the enemy. The reason is that cruise control tries to get back to the set speed very quickly, thereby maximizing acceleration (that doesn't mean it floors the accelerator, just runs it at a much higher rate than a person would normally do). And when going down hill, cruise control puts the brakes on to prevent the speed from going over the set speed, thereby wasting energy.

The only time cruise control can approach a human is if the terrain is very very flat. Even in Texas there aren't many places like that. Of course, it should be possible to design a cruise control that would minimize energy use, but I don't know of any.