Braking distance realism

ESC is being remade, current one is not working too well currently.

Another thing missing is audible feedback, tires don't start making noises until you are really sideways, while in reality street tires start to complain even without really having car sliding much, proper hard cornering is enough IRL to make tires complain.

You might find this interesting too, they are investigating it, wheelspin seems to happen very easily in some situations:
https://beamng.com/threads/exploit-of-physics-flaw-or-what.66581/

Try to put sporty car's tires to basic level car and see how that changes behavior, Diamondback mentioned that those basic tires might not be the best.

Also set FOV to 36 or so, that takes long time to get used to, but when you get used to it driving fast is much better, lack of audible feedback from tires makes it pretty hard to catch slide enough early with default FOV, but with physically correct FOV it becomes much easier. You can find FOV calculators from net, also you can measure gauges on your screen and estimate if you are way off or close to real 1:1 measures.
That helps a lot with gauging where corners of cars are.

Also disabling all camera shaking and movement helps to see what car is doing.

 

Is it TC then that is not working, because this is not quite right:


There is no problem with car handling corners when pushing harder without esc, but with esc on car just does not want to go, system is limiting performance very hard.

It is much worse with ETK K-series, red RWD variant is not wanting to go even on straights as system is cutting in all the time and even tiniest amount of turning kills engine power completely.

It might be just a tuning issue, but real world systems are not so intrusive.

Of course could be trouble with tires etc. too, causing too much slip too easily, but it just is not good driving experience currently.
--- Post updated ---
K-Series is like this, there is hardly any slip, but TCS light is flashing, I think that with TC speed issue fixed there is now some other issue in it showing up, TC activates way before it is needed, could it be that some slip spikes in physics triggers it?

If there would be button to turn of TCS or ESC alone instead of single button for both, that would be useful, maybe that is part of driving modes thing then.

That TC I set up long time ago, before TCS speed issue was fixed still works better in K-series as it is not kicking in during straights, 1st lap with mine, 2nd lap with vanilla:


I guess my TCS allows more than 10% slip, not sure, but loads more slip on wheels debug than with Vanilla TC, still there is zero problems with spinning or losing control with it.

 

Just from playing around, the ABS in the game feels way too aggressive. I manage to stop in a much shorter distance threshold braking without ABS, maybe try that?

 

Also TC I think.

I did set TC to 0.055 from 0.04 (not sure if it is percent of slip) with K-series and got lot of improvement without loosing car stability.

If using TC alone, then 0.04 might be needed to keep sportier RWD K-series models in check, but as ESC is also active even values up to 0.07 work OK, did test as high as 0.12 and that started to be properly fun allowing some sliding and not saving most foolish driving mistakes, but still not spinning easily.

ABS also seems to get status of grip or something when pressing brakes and then not updating status of grip unless there is some sudden change like steering, gear shifting, etc.

With more tuning, I think that ABS could be much better at stopping car, but more importantly if it would constantly update during steady braking it might perform better.

Not sure if data about slip is also spiky/noisy that ABS sees and then gets more cautious because of spikes, haven't tested that and probably don't even know how to test that.

With Bluebuck I had brake pressure set so that it is close to locking and used button to brake, so that was bit worse than perfect threshold braking, but easy to repeat.

 

A very interesting discussion.

@Devs: What is the difference between realistic and arcade ABS? (Anti Lock brakes). Does this setting also affect ESC?



It should be noted that stopping distances between modern trucks and modern cars are pretty similar. Higher mass is compensated by larger tires (more rubber on the road) larger brakes (more braking power) and finally... alll that weight creates more ground pressure which again increases maximum braking friction.

As such, it is really a bad idea to drive with insufficient distance to to truck ahead.... its brakes most likely are of quite similar stopping power and you may find yourself in a brutal, possible fatal aft accident should it brake suddenly.


It should also be noted, that since kinetic energy increases with the square of the velocity (in english... 2 times the speed is FOUR times the kinetic energy and as such braking distance) that even if you have great tires and great brakes.... you will still never compensate the higher speed and energy of driving faster.

It would estimate that even a very brake powerful car stopping from 130 km/h would require more distance than a average modern one from 110 km/h.

Running some calculations:
Vehicle mass: 1500 kg

Speed average vehicle: 110 km/h
Kinetic energy average vehicle @ 110 km/h = KE = 700232 J

Speed brake powerful car: 130 km/h, identical mass of 1500 kg
Kinetic energy brake powerful car @ 130 km/h = KE = 978009 J = 39,67 % more kinetic energy. Unless your sporty car has brakes that are at least 39,67 percent better... it will require more distance to stop from 130 km/h than the average family car will require from 110 km/h.

Assuming identical brake and tire performance, a mere 20 km/h more will significantly increase stopping distance. The higher the base speed... the larger the difference:

Vehicle mass: 1500 kg

KE @ 100 km/h = 578703 J
KE @ 120 km/h = 833333 J (+254630 J)
KE @ 140 km/h = 1134259 J (+300926 J)
KE @ 160 km/h = 1481481 J (+347222 J)
KE @ 180 km/h = 1875000 J (+393519 J)
KE @ 200 km/h = 2314815 J (+439815 J)

Kinetic energy of the same car at an 55 km/h crash test: 175057 J. Yeah.. this is enough to demolish your car as shown in crash test videos... yet look how puny this number is compared to above highway speed numbers.

Regular braking distance shall be 35 meters @ 100 km/h) = 16534 J per metre of brake power:

Estimated stopping distance:

100 km/h = 578703 J = 35 meters
120 km/h = 833333 J (+254630 J) 50,40 meters (+ 15,40 meters)
140 km/h = 1134259 J (+300926 J) 68,60 meters (+ 18,20 meters)
160 km/h = 1481481 J (+347222 J) 89,60 meters (+ 21,00 meters)
180 km/h = 1875000 J (+393519 J) 113,40 meters (+ 23,80 meters)
200 km/h = 2314815 J (+439815 J) 140,00 meters (+26,60 meters)


Even though the speed increase is always a linear 20 km/h... the same 20 km/h more require more and more meters to annihilate in braking. So yes... even seemingly "small" speed increases will increase your stopping distance quite significantly. 140 km/h compared to 100 km/h almost doubles the required distance already.


Speed > vehicle mass:

Two cars on a frontal collision course. We assume for the purpose of this test that both cars are rigid and dont give in at all.

One small car: 1200 kg mass, 120 km/h speed = 666666 J
One large car: 1600 kg mass, 100 km/h speed = 617284 J = 8 % less even though it is 400 kg heavier.

Assuming again that both cars are rigid and hit each other at a perfect straight angle... the larger heavier car will actually be forced backwards instead of the smaller ligher one.


--> The faster you drive, the higher the risk. Physics cannot be bribed.




There are some special cases where anti lock brakes are inferior to regular brakes: In heavy snow/gravel locking up tires will create a hill of material in front of them, the car literally digs into the ground which increases stopping power. ABS wheels still rotate and avoid the creating of this hill as they keep rolling over the material.

Anti Lock brakes maintain some steering control as they have rotating wheels that can transfer steering torque but even for them - my personal experience at least! - shortly releasing the brakes (if it is clear that maintaining full anti lock brake power will not be sufficient to avoid an accident) can increase the maximum turn in angle of the car. (making a sharper turn than before)

As such, if you are about to hit something and steering evasiveness is not enough, shortly releasing the brakes might just give you just enough turning angle to avoid or lessen a collision.

As always, avoiding to get into such situations in the first place is the best way. Maintain distance, maintain reasonable road speeds and always... always assume that other drives may make a a mistake. Dont be stingy about your tires and brakes..... they may be the only thing standing between you and your furneral.

 

Arcade abs affects everything, realistic only affects cars with abs iirc

 

Using Diamondback's code from wheels.lua I tested few of the cars and some mod cars too:

Skoda Octavia was in video at earlier page 22.5 meters, while Porsche in video was 19.5 meters, stopping from 80kph.

Two vanilla cars that might be somewhere close to cars at video are these:
24.27 1.035 ETK800 854t(A) ABS
22.27 1.128 SBR4 RWD Base (DCT) ABS

It is pretty close I would say, considering tires are just nodes and beams, not even round, certainly not even done to their final form yet. Also how accurate was measurement of distance on video's situation, we can't know.

However in this group, there is something odd:
26.54 0.947 GrandMarshal V8(A) ABS
26.99 0.932 Moonhawk I6(A) older
26.995 0.931 H-Series Cabster(A)
27.44 0.916 Bluebuck 291 V8 4 Door Sedan (A)
27.81 0.904 Burnside V8 Dual-Matic (A)

For burnside, something like 0.5g would be perhaps more appropriate, for Bluebuck perhaps not too much more than that? That is of course if there are no gameplay reasons for them to have better brakes and also I guess need to consider number of complains of no brakes, two hard brakings and fade is pretty bad, who would like to play that level of realism?

I did also test SBR4 on physical model which I know having 1 meter segments, so I could verify that numbers shown by lua program are correct, recorded video, analyzed frame by frame.

Anyway it is interesting to see how cars stand in relation to each other.

 

I imagine decreasing the brake force with the burnside might make it a little more driveable because it won't be able to overheat its brakes as quickly. Also, having driven a car very similar to the bluebuck (a 68 impala) on modern tires, there is no way it could have locked up on dry pavement. Even slamming the brakes as hard as I could was equivalent to about 75% brake force on a modern car at most.

 

Reading those old Car Life magazines, it seems that locking up was not a thing even with old tires, until brake boosters arrived.

Plymouth Fury III VIP was not very good with brakes, around 0.5g only and by 1966 that was unacceptable, but at 50's probably normal.

Ferrari SF15-T took 7 meters to stop from 60mph according to page Diamondback linked.

That is 5.24g as average if I did numbers correctly, I'm not sure about my math, but would that be 1.3 seconds as stopping distance was 7 meters?

I think that my face would fall off with that kind of slowdown. Hitting wall 19kph with SBR4 only gets me 3.7g.