美國時間10 月7 日，特斯拉發表官方博客「Model 3 achieves the lowest probability of injury of any vehicle ever tested by NHTSA」，宣布Model 3 成為美國國家公路安全管理局有史以來測試過的最安全的車輛（車禍時致傷機率最低的車型）， Model S 與Model X 則緊隨其後。

早在17 天前，也就是9 月20 日，馬斯克就在推特上說，特斯拉會在NHTSA 正式公佈測試數據後發布「汽車安全物理學」文章，「Yes, when it comes to physics , make sure Newton is on your side。」（是的，當涉及到物理時，必須確保牛頓在自己這一邊。）

特斯拉的此次發布，不僅證明電動汽車可以做得很安全，更從物理原理、也就是馬斯克念念在茲的第一性原理出發，推導出電動汽車原本就能在結構上做得比燃油車更安全、更易於操縱、有更好的駕乘體驗。

在已經被NHTSA（美國高速公路安全管理局）認證為車禍致傷機率最小/第二小的 Model S和 ModelX 車身架構基礎之上，我們繼續將 Model 3 設計成有史以來最安全的汽車。如今，Model 3 不僅在 NHTSA 安全測試中的每一個大項和小項都取得了 5 顆星的成績，還成為了 NHTSA 安全測試史上致傷機率最小的車型。

Model 3 後驅長續航版的碰撞測試是 NHTSA 新車碰撞測試（NCAP）中的一環，測試內包括了大量的正面、側面，以及翻滾碰撞測試，並從中計算出車禍造成傷亡的概率。

根據 NHTSA 的數據，Model 3 的乘客在碰撞中受傷的概率，要明顯低於市面上其他車型。此前 NHTSA 對 Model S/X 的碰撞測試結果，則僅次於Model 3，排在了第二跟第三位。這也使得特斯拉成為 NHTSA 歷史上測試過最安全的汽車品牌。我們相信 Model 3 的其他版本，包括雙電機性能版，在未來接受碰撞測試時也會表現出同樣優秀的結果。

除了接近 50：50 的前後配重比，Model 3 還擁有極低的極慣性矩，這意味著車內重量最大的零件就位於車輛重心的附近。所以即使 Model 3 沒有所謂的“引擎”，卻依然擁有中置引擎汽車類似的動態表現，因為它有“中置電池組”，而 Model 3 後驅版的電機正好位於後輪軸之上。這樣的車身設計不僅保證了車輛的靈活性和操控感，還將轉向動能最小化，從而增強了車身的穩定性。

9月20日，馬斯克就曾完整解讀過「極慣性扭」這一概念。在馬斯克看來，要做好汽車的安全設計，關鍵在於用好物理原理，「確保牛頓在自己這一邊」。而 Model 3 安全設計的關鍵結束點就在於其極慣性扭做的比其他任何量產車都要好。這對車輛安全、操控性和駕乘感受起到了非常重要的作用，因而是汽車一個非常重要的指標。

馬斯克說，不能只看到前後配重比 50：50 這個指標，因為，就算 50：50了，如果質量很大的汽車部件依然遠離重心，車輛的操控性依然會不好。從這個角度出發，啞鈴的質量分佈是不好的，而旋轉陀螺的質量分佈是好的。

馬斯克還提供了對「極慣性扭」的術語解釋：在汽車世界中，這個術語指的是任何汽車的轉向阻力。要弄清楚單個汽車的極矩，您需要分別知道汽車所有部件的重量，以及每個部件與汽車重心的距離。然後將每個部件的重量乘以其距汽車重心的距離的平方。因此，當重量較重的汽車部件遠離汽車重心時，會出現較大的極性慣性矩。更簡單的解釋：保持較重的汽車部件靠近汽車重心，以降低汽車的極矩問題。

跟Model S/X一樣，Model 3也從純電的動力架構中得益良多，包括剛性極高的乘客艙，經過強化的電池組，還有極低的車身重心。這些基礎項目能夠有效避免外界因素對車身以及電池組的干擾，降低翻車的風險，以及有系統地把衝擊力從車艙內分散出去——還為車前緩衝區吸能效果的進一步優化提供了基礎。

當正面碰撞發生時，Model 3的緩衝區能夠有效控制乘客艙的減速，其先進的乘員約束系統與安全帶預張緊器、限力器會協同保證車內乘客的安全。經過特殊設計的安全氣囊可以在傾斜或偏置碰撞中有效保護乘客的頭部，主動通風孔則會自動調整氣囊內的氣壓以充分優化保護效果。以上所有功能，都是Model 3 5 星安全表現的體現。

這個結構包括了高強度的鋁製緩衝梁，以及佈置在車輛下前方的活動連接桿。此外還有額外的斜梁，在整個結構沒有被碰撞直接影響到的情況下，將衝擊力轉移到防撞樑上。前懸掛頂部連接著強度極高的馬氏體不銹鋼樑，在嚴重的碰撞中能夠進一步吸收衝擊力。整個結構表面的後部被設計成“U”形。在碰撞中能夠彎曲。即使在雙電機全驅車型上，這套結構依然能高效工作。

Model 3 還保持著 NHTSA 測試車型裡側面撞擊影響最低的記錄。與正面碰撞不同，側面碰撞留給緩衝區的操作空間並不大，所以我們在盡可能窄的空間裡面放入了我們設計的柱狀結構和側梁，以盡可能吸收更多的衝擊力。這些部件與高剛性車身、強化電池外殼一起保護車輛免收側面碰撞的影響。由於車身設計對車內空間干擾不大，我們的側氣囊體積可以做得更大，從而更好地保護車內乘客。

在美國道路上，翻車事故是人員傷亡的主要來源。特斯拉車型的設計基礎是通過盡可能下置的電池組以及融入前後軸的電機，營造極低的車身重心，從而大大減小翻車的可能性。當發生可能引起翻車的碰撞時，我們的內部測試表明，Model 3的車頂能夠承受車身四倍的重壓，而NHTSA的標準只要求到3倍。

許多車企都希望自己生產的車型在碰撞測試中取得優秀的表現，每一家車企都宣稱自己的產品是安全的。但當事故真實發生時，這些測試都表明，如果你開的是一輛特斯拉，那你受傷的機率是最小的。

Based on the advanced architecture of Model S and Model X, which were previously found by the National Highway Traffic Safety Administration (NHTSA) to have the lowest and second lowest probabilities of injury of all cars ever tested, we engineered Model 3 to be the safest car ever built. Now, not only has Model 3 achieved a perfect 5-star safety rating in every category and sub-category, but NHTSA’s tests also show that it has the lowest probability of injury of all cars the safety agency has ever tested.

NHTSA tested Model 3 Long Range Rear-Wheel Drive as part of its New Car Assessment Program, a series of crash tests used to calculate the likelihood of serious bodily injury for front, side and rollover crashes. The agency’s data shows that vehicle occupants are less likely to get seriously hurt in these types of crashes when in a Model 3 than in any other car. NHTSA’s previous tests of Model S and Model X still hold the record for the second and third lowest probabilities of injury, making Tesla vehicles the best ever rated by NHTSA. We expect similar results for other Model 3 variants, including our dual-motor vehicles, when they are rated.

In addition to its near 50/50 weight distribution, Model 3 was also designed with an extremely low polar moment of inertia, which means that its heaviest components are located closer to the car’s center of gravity. Even though Model 3 has no engine, its performance is similar to what’s described as a “mid-engine car” due to its centered battery pack (the heaviest component of the car) and the fact that Model 3’s rear motor is placed slightly in front of the rear axle rather than behind it. Not only does this architecture add to the overall agility and handling of the car, it also improves the capability of stability control by minimizing rotational kinetic energy.

Like Model S and Model X, Model 3 benefits from its all-electric architecture and powertrain design, which consists of a strong, rigid passenger compartment, fortified battery pack, and overall low center of gravity. These safety fundamentals help to prevent intrusion into the cabin and battery modules, reduce rollover risk, and distribute crash forces systematically away from the cabin – all while providing the foundation for our superior front crumple zone that is optimized to absorb energy and crush more efficiently. Here, you can see how the orange internal combustion engine block is thrust towards the cabin during a frontal impact test:

In frontal crashes, Model 3’s efficient front crumple zone carefully controls the deceleration of occupants, while its advanced restraint system complements this with pre-tensioners and load-limiters that keep occupants safely in place. Specially designed passenger airbags are shaped to protect an occupant’s head in angled or offset crashes, and active vents dynamically adjust the internal pressure of the frontal airbags to optimize protection based on the unique characteristics of the crash. Front and knee airbags and a collapsible steering column work to further reduce injury, all contributing to Model 3’s 5-star rating in frontal impact.

In pole impact crashes, in which a narrow obstruction impacts the car between the main crash rails, energy-absorbing lateral and diagonal beam structures work to mitigate the impact. This includes a high-strength aluminum bumper beam, a sway bar placed low and forward in the front of the car, cross-members at the front of the steel subframe that are connected to the main crash rails, and additional diagonal beams in the subframe that distribute energy back to the crash rails when they aren’t directly impacted. An ultra-high strength martensitic steel beam is also attached to the top of the front suspension to further absorb crash energy from severe impacts, and the rear part of the subframe is shaped like a “U” and buckles down when impacted. These structures continue to be effective even when a front motor is added for Model 3 Dual-Motor All-Wheel Drive, due to the fact that the subframe is designed to pull the nose of the motor down and out of the way.

Model 3 also has the lowest intrusion from side pole impact of any vehicle tested by NHTSA. Unlike frontal crashes, there is little room for crumple zone in a side impact, so we patented our own pillar structures and side sills to absorb as much energy as possible in a very short distance. These structures work alongside the vehicle’s rigid body and fortified battery architecture to further reduce and prevent compartment intrusion. With less intrusion into the cabin, our side airbags have more space to inflate and cushion the occupants inside.

Rollover accidents are a significant contributor to injuries and deaths on U.S. roads. Tesla’s vehicle architecture is fundamentally designed to have a very low center of gravity, which is accomplished by placing the heavy battery pack and electric motors as close to the ground as possible. In the event that a rollover does occur, our internal tests show that the Model 3 body structure can withstand roof-crush loads equivalent to more than four times its own weight and with very little structural deformation. NHTSA’s standards only require that cars withstand loads of three times their own weight.

Many companies try to build cars that perform well in crash tests, and every car company claims their vehicles are safe. But when a crash happens in real life, these test results show that if you are driving a Tesla, you have the best chance of avoiding serious injury.