What does the adhesion size in Subject 4 mean?

[MacAiden]

Subject 4 adhesion size is the product of vehicle weight and road surface adhesion coefficient. The following is an introduction to the driver's license: 1. Introduction to the driver's license: The full name of the driver's license is the motor vehicle driver's license, also known as the "driving license". It is the certificate required by law for motor vehicle drivers. 2. The examination process for the driver's license: (1) Subject 1: Traffic regulations and related knowledge, with a full score of 100 points, and a passing score of 90 points or above. (2) Subject 2: Field driving, only divided into pass and fail. (3) Subject 3: Road driving test, all tests are conducted under electronic monitoring + traffic police examination, making the road test more fair. (4) Subject 4: Theoretical test on safe and civilized driving knowledge.

[Philip]

When I first started learning to drive and was taking the subject four test, the instructor explained that the level of adhesion refers to how firmly the tires can grip the road. Simply put, it's the strength of friction between the tires and the road surface during braking or turning. High adhesion means the car is stable; low adhesion increases the risk of skidding. Especially when driving in rain or snow, the road becomes slippery, adhesion decreases, braking distance lengthens, and the risk of losing control and causing an accident rises. During my training, I also practiced simulation questions on gradually slowing down on slippery roads and maintaining a safe distance. Regular maintenance should also pay attention to tire conditions, such as severe tread wear or insufficient tire pressure, which can reduce adhesion. In short, the subject four test covers this to remind us that safety comes first and not to take risks with sudden turns or brakes under complex conditions. Understanding the level of adhesion has made my driving mindset much steadier, helping me make fewer mistakes on the road in the future.

[KimberlyLee]

As someone who has been teaching driving for a long time, the concept of adhesion is a core safety principle in the Subject 4 exam. It directly affects a vehicle's stability during braking and steering. When adhesion is weak, such as on wet or icy roads, tires lose grip, making the car prone to skidding or even rolling over. I recall a student sharing that braking distances on highways are noticeably longer in rainy conditions—this is a clear sign of reduced adhesion. Exam questions often involve scenarios like adjusting speed or using ABS, all of which depend on adhesion strength. Practically, I recommend regularly checking tire pressure and tread wear, and switching to all-season tires for better overall grip. Anticipating road conditions and maintaining a safe distance while driving can effectively manage changes in adhesion. Integrating these principles into daily habits ensures safer and more reliable driving on the road.

[LaCharlie]

As a seasoned driver with decades of experience, I've learned that traction is essentially how well the tires can grip the road. When traction is low, the wheels can slip as if they're coated in oil. One winter, I nearly lost control on icy roads when braking, and only managed to stabilize by gently easing off the accelerator. In the driving theory test (Subject 4), this concept refers to the friction between tires and the road during braking, which becomes especially crucial in muddy or snowy conditions. For regular maintenance, I opt for quality tires and ensure proper tire pressure. Driving slowly and cautiously is always safer, particularly when traction is limited.