In the properties window, click on the Betas tab on the left-hand menu.
Cars in Build 39 are fully modular. Every part—including the engine, battery, muffler, brakes, suspension, and individual tires—has its own condition bar. Bumping into zombies or crashing into trees realistically degrades these parts, leading to engine stalls or dangerous tire blowouts mid-flight. project zomboid build 39 upd download
Here is the mandatory mod list for Build 39: In the properties window, click on the Betas