Hey Noel, I ran your script through a couple of AI models (as im new to Zomboid modding scene) it may be total rubbish, but felt like id report here incase it is of any use to you.

GPT: Problem explained:

```
Potential Culprit: Missing or Partially Spawned Suspension/Wheels
If a vehicle spawns with suspension, brakes, or tires missing, or even with a condition of 0, and then goes offscreen:

PZ’s physics engine sometimes has a freak-out when that vehicle re-renders — it’s like the game "forgets" how to rest it properly.

This can result in vehicles spawning in mid-air slightly or clipping terrain, then falling or flipping when physics re-activate.

Especially if FullAssemblyDelete = true, and the mod decides to remove tire + brake + suspension, the car can look parked but act cursed when you come back later.

Suggestions:
Try disabling FullAssemblyDelete and instead just use the individual component chances. It gives more granular control and reduces the chance of truly unstable spawns.

Avoid setting chances too high for critical parts like tires, suspension, or brakes. No tires = wonky physics. No suspension = clown car flips.

Use UVDebugPrint = true to watch console logs when vehicles spawn. It’ll help catch what was removed and where.
```



Would any of these 'fixes' detract from the mods intended purpose?:

```
Would a physics-safety patch “detract” from the mod’s goal?
Not really. In fact, I'd argue it could enhance it.

Here's why:

The intention is visual and gameplay immersion — "oh no, this car’s screwed!" — not "oh no, this car is now airstriking my safehouse."

A patch that, say:

Forces a vehicle to rest on flat tires instead of none

Replaces ultra-critical missing parts like all four wheels with ruined versions

Or despawns vehicles entirely if they'd be unrenderable messes
...would just be ensuring PZ doesn’t nuke itself with its janky vehicle physics.

✅ Balanced Fix Ideas:
If you want to stay lore-friendly:

Post-spawn override:

Check if vehicle has zero suspension/brakes/tires → replace with condition 1 broken parts or deflated tires.

Fallback wheel logic:

If FullAssemblyDelete triggers total removal, instead of deleting the entire assembly, it:

Deletes the tire and brake, but sets suspension to 1 condition, so physics still anchor it.

Invisible "wheel stand" part:

If all else fails, attach a dummy invisible part just to stabilize physics. Not visible, but keeps the car grounded.```

Claude also went the same route.

```
Key Changes Made:
1. Never Remove Critical Physics Components

Tires, brakes, and suspension are never completely removed (setInventoryItem(nil))
Instead, they spawn with condition = 1 (extremely damaged but still present)

2. Enhanced Tire Handling

Severely damaged tires get minimal air (1 unit) instead of being removed
This maintains ground contact for physics calculations

3. Conservative Engine/Brake Degradation

Replaced the potentially problematic logarithmic formula with simple percentage reduction
Ensures conditions never go below 1 (which could cause physics issues)

4. Safe Assembly Damage System

FullAssemblyDelete mode now damages components instead of removing them
Maintains structural integrity while still providing the "unmaintained" experience

5. Better Error Prevention

Added more condition checks to prevent edge cases
More conservative mathematical operations

Benefits:

Maintains mod purpose: Vehicles still spawn in poor condition requiring repairs
Prevents physics glitches: All critical components remain present for stability
Gameplay impact preserved: Players still need to repair/replace damaged parts
Performance safe: No risk of vehicles moving/flipping when offscreen

User Experience:
Players will still encounter:

Nearly flat tires that need air and replacement
Extremely worn brakes that barely work
Damaged suspension affecting handling
All other non-critical part removals (mufflers, windows, etc.)

The vehicles will still feel "unmaintained" and require significant work, but won't cause the physics instability issues you were experiencing.
```