how much side force can CT exert to resist a vehicle shoving you out of your lane?

[roadrunner32]

This question comes to mind after the car on my right tried to enter my lane while I was on FSD in my Y. I retrieved the footage and viewed it on the computer's big screen. I could definitely see that he came out of his lane at least 2 feet maybe 3. I looked at a different camera angle and saw that he did shove me over about a foot it was enough force to fold my side mirror in and damage my Y's body. It was really dangerous because there was a concrete barrier (no shoulder) on my left normally about 2 feet away and while cars are flying past at 75mph in the posted 55mph interstate. The barrier is so close I will not drive in that lane without autopilot. which does a great job keeping the car in line. For that reason alone people should buy a Tesla and why I want to trade in my 2018 Honda Ridgeline for a CT. I just don't feel safe in it after driving a Tesla for three years.

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[rrizzi7210]

Without diving too deep here, but initial thought is a simple momentum formula of m1v1+m2v2=m1v1′+m2v2′ which assuming a car is going to make contact with a CT from the side while traveling in the same direction, we find that on average the mass of a CT is about twice that of a typical ICE automobile. Therefore, without taking in account static friction in the same vector (direction) as the movement (meaning sideways in this case), a CT will experience half of the velocity change in the direction of the impact from the other vehicle since mass is about twice compared to the other vehicle.

The real issue of course is while driving in FSD, how will FSD react to the lateral force upon impact? Will FSD turn in the direction of the impact to maintain its forward angle or not. Will the impact cause a "Take Over Immediately" for the driver? I don't know, but whatever the case, a CT weighs in around 3,100 kgs so a CT has the advantage against the average five-seater automobile, which I find has a mass of around 1,600 kgs.

The above is from my best effort memory, and below this sentence is what ChatGPT returned with my prompt:

Explain m1v1+m2v2=m1v1′+m2v2' as it relates to the physics of two cars side-swiping each other at relatively low speeds.

where:

• m1,m2 are the masses of two cars,
• v1,v2 are their initial velocities,
• v1′,v2′ are their velocities after the interaction.

Now, let's apply this concept to two cars side-swiping each other at relatively low speeds:

1. Side-Swiping at Low Speeds
A side-swipe collision occurs when two vehicles make contact along their sides while traveling in the same or opposite directions. This is typically a glancing collision, meaning momentum is transferred mostly in the lateral direction (sideways) rather than front-to-back.

• If two cars brush against each other while moving in the same direction, the force of impact is small, and the change in velocity is minor.
• If one car is stationary or moving in the opposite direction, momentum transfer may cause one vehicle to yaw (rotate slightly) or experience a lateral push.

2. Momentum Conservation in a Side-Swipe
In an idealized elastic or partially inelastic collision:

where:

• The x-direction represents movement along the road (forward motion).
• The y-direction represents lateral movement (sideward forces from the impact).

Since a side-swipe usually involves a glancing blow, the momentum in the x-direction (forward motion) is mostly unchanged. However, in the y-direction, the impact can cause minor lateral acceleration, resulting in a slight change of lane, swerving, or body panel deformation.

3. Factors Affecting the Outcome

• Mass Difference: If one car is much heavier (e.g., a Cybertruck vs. a sedan), the smaller car will experience greater acceleration sideways due to Newton's Second Law: F=maF = maF=ma.
• Speed Difference: A higher relative speed difference can result in more force being transferred.
• Friction & Road Conditions: If the road is wet or slippery, the affected vehicle may lose traction and skid.
• Angle of Impact: A shallow impact angle results in a small force, while a sharper angle can induce more yaw (rotation).

Conclusion

In a low-speed side-swipe, momentum in the forward direction is mostly conserved, but some lateral momentum is exchanged, causing a small sideways push. The lighter vehicle experiences more displacement due to the force transfer. However, since friction with the road is high, most side-swipe incidents don’t result in major loss of control, unlike head-on or T-bone collisions.

When ChatGPT is prompted with:

how does Tesla's FSD system react when side-swiped by another vehicle while traeling at highway speeds?

It returns some things I did not know:

Tesla's Full Self-Driving (FSD) system and Autopilot are designed to respond to collisions, including side-swipes, using a combination of sensors, cameras, and onboard AI. At highway speeds, if a side-swipe collision occurs, Tesla’s system reacts based on real-time sensor fusion data from cameras, ultrasonic sensors, and radar (if equipped). Here’s how it typically handles such an event:

1. Immediate Detection

• Tesla’s blind spot monitoring, side cameras, and ultrasonic sensors detect the approaching vehicle before impact.
• If the impact is detected (via sudden lateral acceleration, pressure sensors, or camera analysis), the system logs the event and may alert the driver instantly.

2. Stability Control & Evasive Action

• The car’s Electronic Stability Control (ESC) and Traction Control System (TCS) kick in to help maintain lane position and prevent loss of control.
• If the impact pushes the car sideways, FSD will attempt corrective steering to keep the car in its lane.
• If the impact is strong enough to cause a significant deviation, Automatic Emergency Steering (AES) may activate to minimize further collisions.

3. Adaptive Speed & Lane Adjustment

• If FSD detects that staying in the same lane is unsafe, it may attempt to slow down gradually to regain stability.
• If a safe lane change is possible (and legal), it may guide the car away from the impact zone.
• If no safe maneuver is possible, it will prioritize keeping the vehicle straight and stable.

4. Alerting the Driver & Emergency Response

• If the system determines manual intervention is needed, it will sound an audible alarm and display warnings on the instrument cluster.
• If the collision is severe, the system may automatically contact emergency services via Tesla’s eCall system.

5. Recording the Incident (TeslaCam & Sentry Mode)

• Tesla’s cameras are always recording while FSD is engaged, so the side-swipe event is logged in TeslaCam (dashcam footage).
• This footage can be reviewed by the driver or used for insurance and accident investigation.

6. Post-Collision Adjustments

• If damage is detected in critical systems (e.g., sensors, brakes, steering), the car may limit FSD functions and suggest manual driving or a safe pull-over.
• Tesla’s over-the-air diagnostics may detect sensor misalignment and advise a service check.

Final Thoughts

At highway speeds, Tesla’s FSD is designed to mitigate the impact of a side-swipe rather than fully prevent it. The main goal is to keep the vehicle stable, reduce secondary collisions, and assist the driver in regaining control. If you’re in FSD mode when this happens, it won't take extreme evasive action (like swerving into another lane) unless it can verify a clear escape route.

 

[Model3Guy]

Without diving too deep here, but initial thought is a simple momentum formula of m1v1+m2v2=m1v1′+m2v2′ which assuming a car is going to make contact with a CT from the side while traveling in the same direction, we find that on average the mass of a CT is about twice that of a typical ICE automobile. Therefore, without taking in account static friction in the same vector (direction) as the movement (meaning sideways in this case), a CT will experience half of the velocity change in the direction of the impact from the other vehicle since mass is about twice compared to the other vehicle.

The real issue of course is while driving in FSD, how will FSD react to the lateral force upon impact? Will FSD turn in the direction of the impact to maintain its forward angle or not. Will the impact cause a "Take Over Immediately" for the driver? I don't know, but whatever the case, a CT weighs in around 3,100 kgs so a CT has the advantage against the average five-seater automobile, which I find has a mass of around 1,600 kgs.

The above is from my best effort memory, and below this sentence is what ChatGPT returned with my prompt:

Explain m1v1+m2v2=m1v1′+m2v2' as it relates to the physics of two cars side-swiping each other at relatively low speeds.

where:

• m1,m2 are the masses of two cars,
• v1,v2 are their initial velocities,
• v1′,v2′ are their velocities after the interaction.

Now, let's apply this concept to two cars side-swiping each other at relatively low speeds:

1. Side-Swiping at Low Speeds
A side-swipe collision occurs when two vehicles make contact along their sides while traveling in the same or opposite directions. This is typically a glancing collision, meaning momentum is transferred mostly in the lateral direction (sideways) rather than front-to-back.

• If two cars brush against each other while moving in the same direction, the force of impact is small, and the change in velocity is minor.
• If one car is stationary or moving in the opposite direction, momentum transfer may cause one vehicle to yaw (rotate slightly) or experience a lateral push.

2. Momentum Conservation in a Side-Swipe
In an idealized elastic or partially inelastic collision:

where:

• The x-direction represents movement along the road (forward motion).
• The y-direction represents lateral movement (sideward forces from the impact).

Since a side-swipe usually involves a glancing blow, the momentum in the x-direction (forward motion) is mostly unchanged. However, in the y-direction, the impact can cause minor lateral acceleration, resulting in a slight change of lane, swerving, or body panel deformation.

3. Factors Affecting the Outcome

• Mass Difference: If one car is much heavier (e.g., a Cybertruck vs. a sedan), the smaller car will experience greater acceleration sideways due to Newton's Second Law: F=maF = maF=ma.
• Speed Difference: A higher relative speed difference can result in more force being transferred.
• Friction & Road Conditions: If the road is wet or slippery, the affected vehicle may lose traction and skid.
• Angle of Impact: A shallow impact angle results in a small force, while a sharper angle can induce more yaw (rotation).

Conclusion

In a low-speed side-swipe, momentum in the forward direction is mostly conserved, but some lateral momentum is exchanged, causing a small sideways push. The lighter vehicle experiences more displacement due to the force transfer. However, since friction with the road is high, most side-swipe incidents don’t result in major loss of control, unlike head-on or T-bone collisions.

When ChatGPT is prompted with:

how does Tesla's FSD system react when side-swiped by another vehicle while traeling at highway speeds?

It returns some things I did not know:

Tesla's Full Self-Driving (FSD) system and Autopilot are designed to respond to collisions, including side-swipes, using a combination of sensors, cameras, and onboard AI. At highway speeds, if a side-swipe collision occurs, Tesla’s system reacts based on real-time sensor fusion data from cameras, ultrasonic sensors, and radar (if equipped). Here’s how it typically handles such an event:

1. Immediate Detection

• Tesla’s blind spot monitoring, side cameras, and ultrasonic sensors detect the approaching vehicle before impact.
• If the impact is detected (via sudden lateral acceleration, pressure sensors, or camera analysis), the system logs the event and may alert the driver instantly.

2. Stability Control & Evasive Action

• The car’s Electronic Stability Control (ESC) and Traction Control System (TCS) kick in to help maintain lane position and prevent loss of control.
• If the impact pushes the car sideways, FSD will attempt corrective steering to keep the car in its lane.
• If the impact is strong enough to cause a significant deviation, Automatic Emergency Steering (AES) may activate to minimize further collisions.

3. Adaptive Speed & Lane Adjustment

• If FSD detects that staying in the same lane is unsafe, it may attempt to slow down gradually to regain stability.
• If a safe lane change is possible (and legal), it may guide the car away from the impact zone.
• If no safe maneuver is possible, it will prioritize keeping the vehicle straight and stable.

4. Alerting the Driver & Emergency Response

• If the system determines manual intervention is needed, it will sound an audible alarm and display warnings on the instrument cluster.
• If the collision is severe, the system may automatically contact emergency services via Tesla’s eCall system.

5. Recording the Incident (TeslaCam & Sentry Mode)

• Tesla’s cameras are always recording while FSD is engaged, so the side-swipe event is logged in TeslaCam (dashcam footage).
• This footage can be reviewed by the driver or used for insurance and accident investigation.

6. Post-Collision Adjustments

• If damage is detected in critical systems (e.g., sensors, brakes, steering), the car may limit FSD functions and suggest manual driving or a safe pull-over.
• Tesla’s over-the-air diagnostics may detect sensor misalignment and advise a service check.

Final Thoughts

At highway speeds, Tesla’s FSD is designed to mitigate the impact of a side-swipe rather than fully prevent it. The main goal is to keep the vehicle stable, reduce secondary collisions, and assist the driver in regaining control. If you’re in FSD mode when this happens, it won't take extreme evasive action (like swerving into another lane) unless it can verify a clear escape route.

What, if any, reaction from FSD will/will not occur for a pending rear end collision from an oncoming vehicle behind a CT ?

 

[rrizzi7210]

Funny that you should ask. I was hit Saturday night at a stop light by a Chevy Silverado that had already stopped too, but rather closely to my rear bumper. The driver claimed he wasn't paying attention when his large dog in the back seat distracted him, and his foot slipped off the brake while he was facing his dog, I suppose.

Anyway, impact was a very low speed which shows some scuff marks and mild indentation. This is the second time in two months I've been hit like this. The first time was so minor, I didn't bother to do any repairs, but this time, the bumper is slightly deformed.

No warnings or notifications on the screen either. CT was in HOLD when it happened and did not move. He backed up a foot, cops came, and he admitted fault, so my insurance said my $500 deductible will likely be recovered since he also had good insurance.

I messed up the video capture too, because I hit the save button AFTER I was in park, which apparently does not save the video. To make matters worse, I drove for another hour and when I got home, the recording was already overwritten.

Next time, I plan to hit the Save button while in Drive, wait 15 mins, and then swap the USB drive with a spare so it has enough time to make sure the videos are committed to storage, just in case there is a delay for the commit. I should have two separate copies at this point.

 

[Model3Guy]

Thanks for your response. I don't believe there was anything the CT could.have done in your situation. I was wondering how it would react to a fast approaching vehicle with an impending rear end collision.
Anyone ?

 

[pricedm]

Funny that you should ask. I was hit Saturday night at a stop light by a Chevy Silverado that had already stopped too, but rather closely to my rear bumper. The driver claimed he wasn't paying attention when his large dog in the back seat distracted him, and his foot slipped off the brake while he was facing his dog, I suppose.

Anyway, impact was a very low speed which shows some scuff marks and mild indentation. This is the second time in two months I've been hit like this. The first time was so minor, I didn't bother to do any repairs, but this time, the bumper is slightly deformed.

No warnings or notifications on the screen either. CT was in HOLD when it happened and did not move. He backed up a foot, cops came, and he admitted fault, so my insurance said my $500 deductible will likely be recovered since he also had good insurance.

I messed up the video capture too, because I hit the save button AFTER I was in park, which apparently does not save the video. To make matters worse, I drove for another hour and when I got home, the recording was already overwritten.

Next time, I plan to hit the Save button while in Drive, wait 15 mins, and then swap the USB drive with a spare so it has enough time to make sure the videos are committed to storage, just in case there is a delay for the commit. I should have two separate copies at this point.

Sucks you have to deal with aftermath of two collisions. Best of luck to you in the resolution.

Sentry mode/Dashcam: You can activate voice commands from steering wheel, then say "Save Dashcam." I also enabled mode: save dashcam on honk. Both of these are saved to a different subfolder in TeslaCam.

 

[DJAlan2000]

Thanks for your response. I don't believe there was anything the CT could.have done in your situation. I was wondering how it would react to a fast approaching vehicle with an impending rear end collision.
Anyone ?

I actually had that happen... Was in the 'fast' lane going about 70 and all of a sudden FSD sped up and changed lanes... Just as I was about to 'take control' because I thought something went wrong, the guy that FSD had seen (I had not!) when shooting on by at about 90 or more...

Oh, and FSD did NOT use the turn signal when it changed lanes, it just sped up to get past the guy that was next to me and went over, pretty much all in one smooth transition... and then ZOOOOOmmmm goes the other car... This was in my Model Y... Which is running 12.6.4 now, but I think it was on 12.5.x.x though as it happened just before the holidays...

I'm just glad it DID happen, or rather that it may have prevented being rear ended at high speed...

 

[roadrunner32]

Funny that you should ask. I was hit Saturday night at a stop light by a Chevy Silverado that had already stopped too, but rather closely to my rear bumper. The driver claimed he wasn't paying attention when his large dog in the back seat distracted him, and his foot slipped off the brake while he was facing his dog, I suppose.

Anyway, impact was a very low speed which shows some scuff marks and mild indentation. This is the second time in two months I've been hit like this. The first time was so minor, I didn't bother to do any repairs, but this time, the bumper is slightly deformed.

No warnings or notifications on the screen either. CT was in HOLD when it happened and did not move. He backed up a foot, cops came, and he admitted fault, so my insurance said my $500 deductible will likely be recovered since he also had good insurance.

I messed up the video capture too, because I hit the save button AFTER I was in park, which apparently does not save the video. To make matters worse, I drove for another hour and when I got home, the recording was already overwritten.

Next time, I plan to hit the Save button while in Drive, wait 15 mins, and then swap the USB drive with a spare so it has enough time to make sure the videos are committed to storage, just in case there is a delay for the commit. I should have two separate copies at this point.

I thought I'd lost the video too, until I put the Zip drive in the computer. you have to look at the sentry folder. For me there were several files for each event and one particular one that is interesting is called repeater. AND do you know about the Honk? If you honk it saves it, honking the horn is much more handy than fumbling for the save on the screen. But, you may be correct in that it does not save while in Park. Good luck.

Man You are lucky, I honked at this guy and he did not look at me what so ever for 5 miles. I followed him for that 5 miles before I lost him in traffic.

you know we are driving the safest by far cars that have ever been made and yet this stuff still happens

 

[roadrunner32]

I actually had that happen... Was in the 'fast' lane going about 70 and all of a sudden FSD sped up and changed lanes... Just as I was about to 'take control' because I thought something went wrong, the guy that FSD had seen (I had not!) when shooting on by at about 90 or more...

Oh, and FSD did NOT use the turn signal when it changed lanes, it just sped up to get past the guy that was next to me and went over, pretty much all in one smooth transition... and then ZOOOOOmmmm goes the other car... This was in my Model Y... Which is running 12.6.4 now, but I think it was on 12.5.x.x though as it happened just before the holidays...

I'm just glad it DID happen, or rather that it may have prevented being rear ended at high speed...

I'm sure it sounds crazy to the Ludites and the haters, the sooner we get these crazy people off the roads the better it is for all man kind. I'm refraining from calling our cars EVs and not even calling them Teslas either. They are smart cars. And the opposite smart is?

 

[DJAlan2000]

I'm sure it sounds crazy to the Ludites and the haters, the sooner we get these crazy people off the roads the better it is for all man kind. I'm refraining from calling our cars EVs and not even calling them Teslas either. They are smart cars. And the opposite smart is?

Gotta say, I LOVE IT!! Smart Cars/Trucks!! Tesla's truly are smart cars! Smarter than all the rest in fact (but I won't brag THAT to a non-smart-car owner) and hopefully people will start to realize that they are and maybe, just maybe, they will try driving one.

I say:
Don't get mad at the ICE owners, they can't help it, their brains have been damaged by all those gas fumes. Let them drive whatever they want, there's plenty of oil and plenty of people that will ALWAYS refuse to 'upgrade', just like those that drove carriages and rode horses did when the first cars came out. Eventually though, most everyone came around.

 

[ABILISK]

But smart cars are already a thing… and to call a Tesla that is insulting lol. How about tech cars?

 

[ABILISK]

Eventually though, most everyone came around.

People swore by their Nokias they had to charge once a week too. They wouldn’t dream of having to deal with an Apple or Android phone that would have to be charged daily. Today, everyone has a smart phone.

Tesla adoption will be the same way. Give it til 2035. Every car on the road will be an EV, and 95% of those will be Teslas.

 

[DJAlan2000]

People swore by their Nokias they had to charge once a week too. They wouldn’t dream of having to deal with an Apple or Android phone that would have to be charged daily. Today, everyone has a smart phone.

Tesla adoption will be the same way. Give it til 2035. Every car on the road will be an EV, and 95% of those will be Teslas.

Not sure I agree with you... I doubt Tesla's will be 95% of the market... They will be lucky to (still) have 50% or more of the EV market by 2030... VERY lucky...

BUT, I think they need to come out with one that is 'meaner' looking, seems lots of folks think that Tesla's are 'weak' looking... Never thought about it until someone pointed that out to me, but yeah, other than the CT they kind of are...

 

[roadrunner32]

I actually had that happen... Was in the 'fast' lane going about 70 and all of a sudden FSD sped up and changed lanes... Just as I was about to 'take control' because I thought something went wrong, the guy that FSD had seen (I had not!) when shooting on by at about 90 or more...

Oh, and FSD did NOT use the turn signal when it changed lanes, it just sped up to get past the guy that was next to me and went over, pretty much all in one smooth transition... and then ZOOOOOmmmm goes the other car... This was in my Model Y... Which is running 12.6.4 now, but I think it was on 12.5.x.x though as it happened just before the holidays...

I'm just glad it DID happen, or rather that it may have prevented being rear ended at high speed...

Amazing! I would like to see it documented that FSD can do this?

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