Driving standards

[ejstubbs]

4 hours ago, JDW said:

I get the impression that as well as better brakes, modern engines aren't quite as good at engine braking, maybe because the engine and drivetrain is more efficient and has less drag?

 

Conversely, I have an idea that engine braking in modern ECU-controlled engines of both types might actually be more effective, due to the fact that the system actually shuts off the fuel supply to the cylinders when the engine's in overrun (see also a previous discussion IIRC somewhere on this thread re coasting to save fuel - not these days it doesn't).  If there's no combustion to keep the engine spinning then the rotational energy coming back from the wheels through the drivetrain has to overcome all the pumping losses in the engine (which AIUI are greater in a diesel engine than in a petrol engine, since the compression ratios are higher).

 

If you want to drive something that's really got no engine braking worth speaking of, try a two-stroke motorcycle (but preferably don't try it for very long because they tend not to like it).

 

16 hours ago, JeremyC said:

Or are there more people driving automatics these days? Some modern automatics do provide engine braking, but it depends on the type of gearbox. (I live in Edinburgh and a fair number of our hills are beyond the engine braking capacity of my manual car)

 

It's perfectly possible to downshift manually in every automatic I've driven.  And I've driven both a slushmatic and a twin clutch automatic around Edinburgh and I've never had any trouble using the selector lever or tiptronic to downshift for engine braking to control my speed on our steeper hills.  Very occasionally I may find that the gear I've selected isn't giving me quite the retardation I need on a steep section of an otherwise consistent gradient, and I'll dab the brakes until I regain the speed I want.  But I would never ride the brakes all the way down.

 

Caveat: my car does have a "Coast" setting which will put the auto box in neutral if you lift off the throttle at any speed over 20kmph.  Fortunately it is a user-adjustable setting (only requiring you to navigate through multiple layers of menus, so - again fortunately - the user's chosen setting is persistent) and I have it permanently switched off because I think it's a fundamentally bad idea.  There may be (indeed very probably are) folks out there whose cars have a similar setting and they either like it, or don't even know how to turn it off.

 

2 hours ago, 30801 said:

'Gears to go Brakes to slow'

Quoted in every episode of Rory The Racing Car.

 

That phrase applies to race driving (hence why Rory the Racing Car says it - the clue's in the name) where the objective is to go as fast as possible while staying on the track.  But when driving on public roads we're constrained by many other factors than just track limits - speed limits and other road users being the prime examples.  What's good on the track is often far from good on public roads (though some folks - most of them likely having zero track experience - seem to believe otherwise).

 

And in any case I wasn't advocating using engine braking to slow down, but to maintain a steady speed on a downgrade.  The idea is that you see the steep hill coming, drop a gear while maintaining speed, then maintain your chosen speed on the downhill using the throttle rather than the brake.  It's all part of that thing called "anticipation".  But if I'm doing a steady speed down a steep hill with the engine in overrun of course I'm not going to change down another gear if someone pulls out too close in front of me - I'm going to go for the brake in the first instance, and then do whatever is appropriate to maintain a safe distance to the car in front after that.  So yes: brakes to slow.  And, in fact, gears to go - at an appropriate speed taking all possible constraints into account.

 

6 hours ago, boxbrownie said:

Unfortunately you’d hate being behind me then, one annoying thing on the i3 is anything more than a few tenths of a “G” with the regenerative braking the brake lights come on, as per the international regulations......so if it’s an EV in front don’t blame the driver, blame the TUV 

 

Interesting, I didn't know that.  Do you mean that the brake lights will come on even if all you do is lift off the accelerator (so the car recovers energy as part of the natural slowing down process)?  In that case, I wonder if anyone will suggest that it should be mandated for non-EVs as well, so that at least all vehicles behave alike?  Although I suppose an EV may well decelerate quicker than an IC vehicle if lifting off the accelerator is enough to start it recovering kinetic energy to the battery.  I'll bear it in mind in any case.  All that said, however, none of the examples I've come across recently have been EVs.

 

5 hours ago, JDW said:

large vehicles like HGVs the cruise control will often maintain speed downhill and/or distance from the vehicle in front and sometimes will use the brakes to do so, again meaning they seem to be braking oddly. 

 

That sounds like a form of "adaptive cruise control" which is something quite a few cars have these days, too.  I have driven a rented VW Golf with ACC, but didn't occur to me at the time that the automatic braking would cause the brake lights to come on.  But on reflection, of course, it's obvious that it would.  (FWIW I didn't like the ACC very much and ended up hardly using it, whereas I use the normal CC on my own current car quite a lot.)

 

I suppose with drivers either voluntarily or forcibly being relieved of more and more aspects of the control of their vehicle, it's more and more likely that behaviour that many of us are used to blaming on an "idiot driver" could actually the fault of an "idiot car" - or at least an "idiot algorithm".

[JDW]

4 minutes ago, ejstubbs said:

[...]

I suppose with drivers either voluntarily or forcibly being relieved of more and more aspects of the control of their vehicle, it's more and more likely that behaviour that many of us are used to blaming on an "idiot driver" could actually the fault of an "idiot car" - or at least an "idiot algorithm".

 

I do think this is likely to become more of a 'thing'. I'm no fan of adaptive cruise control either, I prefer to be in control as much as possible, although like you I am comfortable with cruise control on clear open motorways where it's a useful aid. The tech is great but over-reliance or viewing it as a cure-all isn't always the solution. I was speaking to one bus company recently who said they didn't want things like pedestrian collison avoidance on their buses, as although the tech would probably avoid the collision with the pedestrian by stopping the bus, it would likely injure a lot of their passengers in the process. The tech can do one job well, but doesn't have a view of the whole situation. Same with adaptive cruise control. But I can easily think of a couple of scenarios where I wouldn't want to brake when catching the car in front, where the tech would want to. 

[Guest]

8 minutes ago, ejstubbs said:

Interesting, I didn't know that.  Do you mean that the brake lights will come on even if all you do is lift off the accelerator (so the car recovers energy as part of the natural slowing down process)?  In that case, I wonder if anyone will suggest that it should be mandated for non-EVs as well, so that at least all vehicles behave alike?  Although I suppose an EV may well decelerate quicker than an IC vehicle if lifting off the accelerator is enough to start it recovering kinetic energy to the battery.  I'll bear it in mind in any case.  All that said, however, none of the examples I've come across recently have been EVs.

 

There's a regulation that says above a certain threshold of deceleration the brake lights have to show.

It's deceleration that determines when they come on, not pedal movement.  Depending on the car and settings lifting off can do anything between freewheeling and coming to a screeching stop.

[Guest]

15 minutes ago, ejstubbs said:

That phrase applies to race driving (hence why Rory the Racing Car says it - the clue's in the name) where the objective is to go as fast as possible while staying on the track.  But when driving on public roads we're constrained by many other factors than just track limits - speed limits and other road users being the prime examples.  What's good on the track is often far from good on public roads (though some folks - most of them likely having zero track experience - seem to believe otherwise).

 

And in any case I wasn't advocating using engine braking to slow down, but to maintain a steady speed on a downgrade.  The idea is that you see the steep hill coming, drop a gear while maintaining speed, then maintain your chosen speed on the downhill using the throttle rather than the brake.  It's all part of that thing called "anticipation".  But if I'm doing a steady speed down a steep hill with the engine in overrun of course I'm not going to change down another gear if someone pulls out too close in front of me - I'm going to go for the brake in the first instance, and then do whatever is appropriate to maintain a safe distance to the car in front after that.  So yes: brakes to slow.  And, in fact, gears to go - at an appropriate speed taking all possible constraints into account.

 

I used the quote in reference to how drivers are taught these days.

For example:

https://www.learnerdriving.com/ld-system/driving-lessons/gears.htm#:~:text=The basic rule is that,more power from the engine.&text=The basic gear changing rule,change up through the gears.

[boxbrownie]

25 minutes ago, ejstubbs said:

 

Interesting, I didn't know that.  Do you mean that the brake lights will come on even if all you do is lift off the accelerator (so the car recovers energy as part of the natural slowing down process)?  In that case, I wonder if anyone will suggest that it should be mandated for non-EVs as well, so that at least all vehicles behave alike?  Although I suppose an EV may well decelerate quicker than an IC vehicle if lifting off the accelerator is enough to start it recovering kinetic energy to the battery.  I'll bear it in mind in any case.  All that said, however, none of the examples I've come across recently have been EVs.

If you lift off the accel pedal completely yes the brake light will come on, because the regeneration is like applying the brakes fairly firmly, if you lift off the pedal slightly ie not all the way then the retardation is much gentler, it really is a much nicer way to drive a car and once tried ICE vehicles seem old fashioned.

 

Different EVs use this facility in various modes, some you can adjust the retardation with a switch, some you don’t have to (like the i3).

[Enterprisingwestern]

56 minutes ago, ejstubbs said:

If you want to drive something that's really got no engine braking worth speaking of, try a two-stroke motorcycle (but preferably don't try it for very long because they tend not to like it).

 

Driving a Wartburg Knight gives a similar effect, the most frightening vehicle I've ever driven!

 

Mike.

[boxbrownie]

52 minutes ago, 30801 said:

 

There's a regulation that says above a certain threshold of deceleration the brake lights have to show.

It's deceleration that determines when they come on, not pedal movement.  Depending on the car and settings lifting off can do anything between freewheeling and coming to a screeching stop.

Exactly, except that I know of no EV that has enough retardation to “come to a screeching stop”......maybe a little exaggeration? 

[Guest]

36 minutes ago, boxbrownie said:

Exactly, except that I know of no EV that has enough retardation to “come to a screeching stop”......maybe a little exaggeration? 

 

Well, obviously they all have ABS.

[PhilJ W]

I seem to recall on a TV program many years ago (Tomorrows World?) an experimental warning device/lights  that consisted of two triangular amber lights that illuminated when the driver removed his or her foot from the accelerator.  The idea was that it would warn following drivers that the vehicle was about to brake. The lights were mounted either side of the rear number plate IIRC.

[Guest]

10 minutes ago, PhilJ W said:

I seem to recall on a TV program many years ago (Tomorrows World?) an experimental warning device/lights  that consisted of two triangular amber lights that illuminated when the driver removed his or her foot from the accelerator.  The idea was that it would warn following drivers that the vehicle was about to brake. The lights were mounted either side of the rear number plate IIRC.

 

There was something I recall that I think was made by an A level student. When you lift off the throttle very quickly it lit the brake lights on the basis that you had taken your foot off and were about to brake. Gave the bloke behind an extra half second or so warning.

[Jonboy]

I was taught to pass my driving test in 2005, I was taught brakes are cheap, clutch’s are not, so not to engine brake. This was an instructor from one of the national chains of driving schools.

[Reorte]

2 hours ago, Jonboy said:

I was taught to pass my driving test in 2005, I was taught brakes are cheap, clutch’s are not, so not to engine brake. This was an instructor from one of the national chains of driving schools.

I'm wondering if there's a bit of confusion going on by what is meant by engine braking. Using just the engine and not the brakes to slow down, by putting the car into too low a gear for the speed? That's probably not a good idea. Using the engine to hold your speed on a hill though (which might result in it revving a bit higher than normal, but much in the way of that means it's time for a dab on the brakes) - if that's not taught then I find it worrying.

[kevinlms]

7 hours ago, 30801 said:

 

There was something I recall that I think was made by an A level student. When you lift off the throttle very quickly it lit the brake lights on the basis that you had taken your foot off and were about to brake. Gave the bloke behind an extra half second or so warning.

Nowadays, LED'S do that. Yes, LED'S light up quicker than a filament lamp.

[Nick C]

When I did the IAM advanced driving course a couple of years ago, they also insisted on always using the brakes to slow rather than going down through the gears - their manta being "IPSGA" - Information, Position, Speed, Gear, Accelerate

[boxbrownie]

7 hours ago, kevinlms said:

Nowadays, LED'S do that. Yes, LED'S light up quicker than a filament lamp.

And a lot of cars now have the facility when the car senses an emergency stop (by how hard and fast the driver presses the pedal) the brake lights will flash rapidly as this is proven to be more noticeable than a steady lamp.

[Jonboy]

13 hours ago, Reorte said:

I'm wondering if there's a bit of confusion going on by what is meant by engine braking. Using just the engine and not the brakes to slow down, by putting the car into too low a gear for the speed? That's probably not a good idea. Using the engine to hold your speed on a hill though (which might result in it revving a bit higher than normal, but much in the way of that means it's time for a dab on the brakes) - if that's not taught then I find it worrying.

thinking it through it’s possible it’s simply not taught round here, south Oxfordshire, because there are no hills of any significant size to worry about...

[peanuts]

speechless 

 

[boxbrownie]

Same condition as most Uber cars......

[PhilJ W]

I wonder if it was insured and if the driver had a licence?

[Titan]

21 hours ago, Jonboy said:

I was taught to pass my driving test in 2005, I was taught brakes are cheap, clutch’s are not, so not to engine brake. This was an instructor from one of the national chains of driving schools.

 

I do wonder though, almost all the wear on a clutch will be from low speed manouevring and pulling away.  Wear from changing gear would be absolutely minimal by comparison, as the clutch is only slipping for a fraction of a second, and under much less load. 

 

Now I was taught to use the gears to help control speed on a hill, as well as working down through the gears whilst coming to a stop. This was on the basis that if you do that, should something untoward happen you are already in the correct gear for your speed.  I have driven on that basis, and never had a clutch wear out on me, or any gearbox wear for that matter, despite having some quite high mileages on the cars.  I have however got extremely long life out of my pads and discs, the best example was when a reputable garage told me that my discs would probably need replacing at the next service due to being a bit thin, I got another 70,000 miles out of them.  And that was more miles than the car had on it from new when the garage brought it up, so perhaps the previous owner was an advocate of not using the gears...

 

Having said that, quite a bit of the substantially improved brake life is also down to me lifting off early and coasting (in gear) for a little bit when slowing from high speed - letting the air resistance do most of the work instead of the brakes.  As air resistance is the square of the speed, slowing down from 70 to 60 by this method before using the brakes is quite effective, as well as saving fuel due to the engine being spinning fast enough for the fuel to be cut.

 

Either way, I have saved 100's over the years in brake discs and pad replacement, not to mention fuel, and never had a clutch issue.  

[Reorte]

Here's another fool: https://www.bbc.co.uk/news/uk-england-derbyshire-55308066

 

Got to wonder about people who drive like that in the first place, let alone ones who then publically post incriminating evidence.

[PhilJ W]

1 hour ago, Reorte said:

Here's another fool: https://www.bbc.co.uk/news/uk-england-derbyshire-55308066

 

Got to wonder about people who drive like that in the first place, let alone ones who then publically post incriminating evidence.

At the moment the overnight curfew will not be much of a hardship.

[jchinuk]

Regarding the discussion on brakes / engine to slow down, the problem is that all too many drivers use the brakes to slow down prior to a sharp corner, but then fail to select the correct gear for the turn, so the car is frantically trying to pull away once around the corner.  You often notice this when they pull out and fail to accelerate.

 

With reference to EVs, the Nissan Leaf has an "e-pedal" mode, which is essentially "one pedal driving" the car comes to a stop if you lift off the pedal.

 

Given the number of accidents where drivers lose control of automatics by pressing on the accelerator, thinking it's the brake, I fear such accidents and tragedies will become all to common once EVs are the rule, more so in the case of "one pedal", I've driven over 40 years with three pedals.  If I get an EV (or an automatic) do I adapt to using both feet, "right go, left stop" or try to drive one-footed? 

 

I can only find figures from the US, but such driver errors are causing concern there, albeit automatics are far more common.  I have to say that there seem to be equally vociferous arguments from both sides on this issue.

 

jch

[Guest]

6 minutes ago, jchinuk said:

Given the number of accidents where drivers lose control of automatics by pressing on the accelerator, thinking it's the brake, I fear such accidents and tragedies will become all to common once EVs are the rule, more so in the case of "one pedal", I've driven over 40 years with three pedals.  If I get an EV (or an automatic) do I adapt to using both feet, "right go, left stop" or try to drive one-footed? 

 

Accidental acceleration is definitely a thing to be concerned about. Especially if you can do 0-60 in three seconds.

There are systems to mitigate this and may well appear in NCAP ratings at some point.

 

 

As for the two foot thing. No. Who even does that?

 

[boxbrownie]

E-Pedal driving as coined by Nissan is fine, our i3 will do exactly the same thing, the regen is such that using the brake becomes a “last resort” action if there is an unexpected reason to brake suddenly, using the accel pedal and regen to control the speed is a far nice way to drive and much more satisfying as a driver, and more comfortable as a passenger.