adaptive cruise control experience
08-05-14, 09:12 PM
#1
Lexus Fanatic
Thread Starter
iTrader: (20)
adaptive cruise control experience
so i was test driving a car with adaptive cruise, and so i got the sales guy to let me take it on the interstate to try it. i think this is what i did...
1. engaged cruise with stalk and pulled down to 'set' speed.
2. realized it was a bit slow, so i held stalk up to accelerate (increase cruise set speed), and the car very slowly increased speed.
3. pressed adaptive cruise button indicating how many car lengths between my test car and one in front. ok, it's working.
4. changed from 3 car lengths to 2, and my test car sped up a bit to catch up with (get closer to) car in front. cool.
5. car in front decided at last second to brake and exit interstate (i was in right lane behind him, but i wasn't getting off).
6. i tapped the brake lightly (instinctively, because i wasn't sure adaptive cruise would react 'enough'), which of course disengaged the cruise.
7. now, open highway in front, i push stalk up to 'RESume' speed, and the car took off fast, 70, 75, 80, 85!!! i felt like i was in one of those 'unintended acceleration' scenarios.
8. not knowing if the car would ever slow down, i pressed the brake pedal which disengaged the cruise and slowed the car down.
now this is what i think happened.
engaging cruise in step 1 turned on the adaptive cruise automatically (as far as i can tell there was no 'off').
in step 2, when i thought i was making the car go faster, i wasn't because it was held back by the adaptive cruise keeping distance with the car in front, but it WAS increasing the cruise 'set' speed anyway, a lot, unbeknownst to me.
in step 7, i did the cruise resume which then resumed to a much higher set speed than i had intended. with no indication of what the cruise set speed was (if no cars were holding it back), i had no way of knowing what speed the cruise wanted to go.
so i don't know if i have that right, but it seemed somewhat dangerous to the uninitiated. it seems to me the resume cruise should not go faster than the highest speed it had been going when being held back by distance previously.
anyone got a better explanation or understanding?
1. engaged cruise with stalk and pulled down to 'set' speed.
2. realized it was a bit slow, so i held stalk up to accelerate (increase cruise set speed), and the car very slowly increased speed.
3. pressed adaptive cruise button indicating how many car lengths between my test car and one in front. ok, it's working.
4. changed from 3 car lengths to 2, and my test car sped up a bit to catch up with (get closer to) car in front. cool.
5. car in front decided at last second to brake and exit interstate (i was in right lane behind him, but i wasn't getting off).
6. i tapped the brake lightly (instinctively, because i wasn't sure adaptive cruise would react 'enough'), which of course disengaged the cruise.
7. now, open highway in front, i push stalk up to 'RESume' speed, and the car took off fast, 70, 75, 80, 85!!! i felt like i was in one of those 'unintended acceleration' scenarios.
8. not knowing if the car would ever slow down, i pressed the brake pedal which disengaged the cruise and slowed the car down.
now this is what i think happened.
engaging cruise in step 1 turned on the adaptive cruise automatically (as far as i can tell there was no 'off').
in step 2, when i thought i was making the car go faster, i wasn't because it was held back by the adaptive cruise keeping distance with the car in front, but it WAS increasing the cruise 'set' speed anyway, a lot, unbeknownst to me.
in step 7, i did the cruise resume which then resumed to a much higher set speed than i had intended. with no indication of what the cruise set speed was (if no cars were holding it back), i had no way of knowing what speed the cruise wanted to go.
so i don't know if i have that right, but it seemed somewhat dangerous to the uninitiated. it seems to me the resume cruise should not go faster than the highest speed it had been going when being held back by distance previously.
anyone got a better explanation or understanding?
08-05-14, 09:24 PM
#2
Lexus Champion
Interesting. In my RX with adaptive cruise it gives the set speed in the display, so I am always aware of what speed it is set to, and will resume to when the car in front if me has moved or I have hit resume on an open stretch.
08-05-14, 09:55 PM
#5
Sounds like you have a solid understanding of what you did. It was likely set at a very fast speed, but the car was being limited due to traffic ahead.
Generally almost all the cars I've evaluated noted the "set" speed fairly prominently within the gauge cluster and/or heads up display.
Should also be noted that some adaptive cruise control system will bring the car to a complete halt, while others may only initiate braking, but require the driver to intervene and bring the car to a full halt if needed.
Generally almost all the cars I've evaluated noted the "set" speed fairly prominently within the gauge cluster and/or heads up display.
Should also be noted that some adaptive cruise control system will bring the car to a complete halt, while others may only initiate braking, but require the driver to intervene and bring the car to a full halt if needed.
08-06-14, 06:53 AM
#7
Lexus Fanatic
Thread Starter
iTrader: (20)
bagwell, it was a prius v.
well well, this seems to capture the matter...
http://wardsauto.com/ar/toyota_prius_cruise_100322
it apparently also confused steve wozniak, co-founder of apple.
http://www.cnn.com/2010/US/02/11/prius.cruise.control/
well well, this seems to capture the matter...
The auto maker believes some of the ’10 Prius cruise-control complaints are the result of confusion over the system’s function, specifically the adaptive cruise-control system dubbed Dynamic Radar Cruise Control, optional in the top-end Prius V.
Introduced in the ’04 Lexus LS 430 and now available on all Lexus models except the SC convertible, the DRCC uses front-mounted radar sensors to detect a vehicle traveling ahead and paces the trailing car’s speed accordingly.
When the lead vehicle slows down, the trailing vehicle slows down. When the lead vehicle speeds up, the trailing vehicle speeds up.
Drivers using that mode can choose between long, medium and short trailing distances, selected by a steering-wheel-mounted button.
Priuses equipped with DRCC also have a conventional cruise-control mode. However, vehicle-to-vehicle with a long-distance setting is the default mode when a driver activates cruise control in the ’10 Prius.
In vehicle-to-vehicle mode, speeds are set either by modulating the gas pedal and tapping down on the stalk at the desired moment, or by manipulating the stalk up or down then releasing.
Tapping the stalk upward boosts speed in 1-mph (0.6-km/h) increments. But if the stalk is moved up and held, speed increases at 5-mph (8-km/h) increments, a fact not detailed in the DRCC section of the ’10 Prius’ owner’s manual.
“That’s where people are getting confused, I think,” Toyota spokesman Dave Lee tells Ward’s. Lee says the rate at which drivers can reach a desired speed using the stalk is much faster than if they accelerated via the gas pedal, taking about one second to advance every 5-mph increment.
“If you’re going 60 (97 km/h) and want to accelerate to 80 (129 km/h), holding that stalk for about four seconds will get it done,” Lee says. “Trying to do it the traditional way in (vehicle-to-vehicle) radar cruise, it will take a lot longer than four seconds to get to 80.”
Introduced in the ’04 Lexus LS 430 and now available on all Lexus models except the SC convertible, the DRCC uses front-mounted radar sensors to detect a vehicle traveling ahead and paces the trailing car’s speed accordingly.
When the lead vehicle slows down, the trailing vehicle slows down. When the lead vehicle speeds up, the trailing vehicle speeds up.
Drivers using that mode can choose between long, medium and short trailing distances, selected by a steering-wheel-mounted button.
Priuses equipped with DRCC also have a conventional cruise-control mode. However, vehicle-to-vehicle with a long-distance setting is the default mode when a driver activates cruise control in the ’10 Prius.
In vehicle-to-vehicle mode, speeds are set either by modulating the gas pedal and tapping down on the stalk at the desired moment, or by manipulating the stalk up or down then releasing.
Tapping the stalk upward boosts speed in 1-mph (0.6-km/h) increments. But if the stalk is moved up and held, speed increases at 5-mph (8-km/h) increments, a fact not detailed in the DRCC section of the ’10 Prius’ owner’s manual.
“That’s where people are getting confused, I think,” Toyota spokesman Dave Lee tells Ward’s. Lee says the rate at which drivers can reach a desired speed using the stalk is much faster than if they accelerated via the gas pedal, taking about one second to advance every 5-mph increment.
“If you’re going 60 (97 km/h) and want to accelerate to 80 (129 km/h), holding that stalk for about four seconds will get it done,” Lee says. “Trying to do it the traditional way in (vehicle-to-vehicle) radar cruise, it will take a lot longer than four seconds to get to 80.”
it apparently also confused steve wozniak, co-founder of apple.
http://www.cnn.com/2010/US/02/11/prius.cruise.control/
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08-06-14, 07:46 AM
#8
Lexus Fanatic
Thread Starter
iTrader: (20)
Generally almost all the cars I've evaluated noted the "set" speed fairly prominently within the gauge cluster and/or heads up display.
however, i've even gone and looked at the online manual to see if it's there and finally found it.http://www.toyota.com/t3Portal/docum.../sec_02-04.pdf
p.233
the 'over to the right' center guage stack is bad enough, but the set speed indicator is on the right of that, so basically in front of the passenger seat. this is a TERRIBLE design.
but yeah, you'd get used to it.
08-06-14, 07:50 AM
#9
Lexus Champion
Well then it's no mystery as to why you missed the display. Hard to notice something like that, several feet away. I absolutely hate the design of having the displays/instrument cluster over in the center of the dash.
08-06-14, 09:37 AM
#10
Lexus Fanatic
Thread Starter
iTrader: (20)
in typical car dealer fashion, the salesperson had NEVER used adaptive cruise, and had NO idea how it worked.
08-06-14, 09:53 AM
#12
But yes, there is a learning curve to newer functions. I now use them quite frequently. Love the ones that can bring the car to a full stop, it's the only way to navigate L.A. stop and go traffic!
08-06-14, 10:04 AM
#13
No, I don't play soccer!
I stopped using adaptive radar cruise control after a similar situation. Someone took an exit though not suddenly. I was approaching a curve in the road but was still in line with them as they slowed down. Fortunately nothing happened. It made me uncomfortable enough to turn it off.
Hoovey, I agree about PCS. First time was because of an idiot crossing three lanes for an exit at the last possible second. I jumped on the brakes, PCS took over. Scared the bejesus outta me!
Hoovey, I agree about PCS. First time was because of an idiot crossing three lanes for an exit at the last possible second. I jumped on the brakes, PCS took over. Scared the bejesus outta me!
08-06-14, 10:34 AM
#14
Lexus Fanatic
Originally Posted by bitkahuna
now this is what i think happened.
engaging cruise in step 1 turned on the adaptive cruise automatically (as far as i can tell there was no 'off').
in step 2, when i thought i was making the car go faster, i wasn't because it was held back by the adaptive cruise keeping distance with the car in front, but it WAS increasing the cruise 'set' speed anyway, a lot, unbeknownst to me.
in step 7, i did the cruise resume which then resumed to a much higher set speed than i had intended. with no indication of what the cruise set speed was (if no cars were holding it back), i had no way of knowing what speed the cruise wanted to go.
anyone got a better explanation or understanding?
You also must have been driving a car with at least a fairly high power to weight ratio, because the computer, no matter what the electronics in it, obviously can't make the car accelerate any faster than the engine or drivetrain gearing is capable of.
08-06-14, 11:23 AM
#15
Unless there is a quirk in the electronics or programming (which, of course, sometimes happens), I don't see where simply having a higher "resume" speed, even unintentionally, should make the car take off like a rocket. The engine's computer, on a "resume" command, should give the fuel-injectors just enough fuel to smoothly and moderately accelerate back up to whatever speed it was (or ended up) pre-set to, whether that speed is 30 or 90. This should apply no matter what the adaptive car-length range or pre-set speed is.
You also must have been driving a car with at least a fairly high power to weight ratio, because the computer, no matter what the electronics in it, obviously can't make the car accelerate any faster than the engine or drivetrain gearing is capable of.
You also must have been driving a car with at least a fairly high power to weight ratio, because the computer, no matter what the electronics in it, obviously can't make the car accelerate any faster than the engine or drivetrain gearing is capable of.