How many centimeters is the maximum allowable deviation for straight-line driving?

[JadeAnn]

Straight-line driving should not deviate more than 30 centimeters to either side. The assessment requirements for straight-line driving are as follows: Requirement 1: The driver must start smoothly and maintain a basic sequence of driving operations. Requirement 2: The driver must correctly handle the steering wheel (primarily using the left hand) and utilize the steering wheel's free play to adjust the driving direction. Requirement 3: The driver must master the timing and methods of gear shifting, being adept at switching between high and low gears at various speeds (including sequential upshifting, sequential downshifting, or skip downshifting). Requirement 4: The driver must be capable of timely and effective use of the brake (anticipatory braking for deceleration).

[MacJesse]

When I was taking my driving test, the straight-line driving section was my nightmare. The instructor in the car kept an eye on me, saying the vehicle couldn’t deviate more than 30 centimeters from the centerline of the lane, or I’d fail the test immediately. I remember being so nervous during practice that my palms were sweaty—I had to focus on the distance ahead and keep both hands steady on the wheel, as even a slight tremor could cause a drift. The standard lane width is about 3 meters, with the centerline as the reference. A 30-centimeter deviation could mean crossing the edge line or entering the opposite lane. Once during a simulation, I drifted 40 centimeters, and the system beeped—my heart sank. Thankfully, I passed later by practicing fine-tuning techniques. Now, even on the highway, I subconsciously remind myself of that limit—staying within 30 centimeters helps avoid collisions. Safety comes first. Though strict, this rule is a lifesaver for beginners.

[DelDiana]

Having driven for over twenty years, I have the deepest feelings about straight-line driving. In daily driving, lane deviation shouldn't be too far; generally, keeping it within 20-30 centimeters is fine. If it exceeds 30 centimeters, the wheels might cross the line or scrape the curb, which is especially dangerous on highways. The lane width is just over three meters, so the centerline position is crucial. Once the deviation becomes excessive, the car body becomes unstable, affecting the safety of vehicles behind. I often tell my friends that looking far ahead is more effective than staring at the hood, and the steering wheel should remain relaxed. Occasionally, on windy days or when fatigued, it's easy to neglect deviations, but the 30-centimeter threshold always brings back alertness. I remember one rainy day on the highway when my car nearly deviated 35 centimeters, but I quickly steadied it to avoid skidding. This isn't just about exam rules—it's the bottom line for protecting yourself and others.

[McCassandra]

As a driving instructor, I emphasize to students the importance of controlling the deviation range when driving straight. Generally, the deviation should not exceed 30 centimeters, which is a strict standard in driving tests. If the vehicle strays too far from the centerline of the lane, it results in failure. I guide students to find distant reference points and hold the steering wheel lightly to avoid rigidity. The designed width of a lane is approximately 3 meters, and a 30-centimeter deviation brings the vehicle close to the edge of the lane markings, which can easily lead to safety hazards. On the training ground, I often set up cones to assist in training, allowing students to experience the critical point. Exceeding the deviation limit not only results in point deductions but may also cause loss of control. In practical situations, beginners often exceed the limit due to nervousness or incorrect operations, but through repeated practice, they can develop good habits. Remembering the 30-centimeter limit can enhance driving stability.

[VanAaron]

Every time I take my child out for driving practice, I emphasize the importance of staying within the 30-centimeter limit for straight-line driving. Exceeding this limit significantly increases risks. The centerline of the lane is the safety axis; straying 30 centimeters could mean entering the opposite lane or hitting a guardrail, raising the chance of an accident. My family often says this standard is a golden number derived from experience. On highways, lanes are about three meters wide, and a slight deviation might seem harmless, but it can accumulate dangerously. From a safety perspective, staying within 30 centimeters helps avoid blind-spot collisions or rear-end accidents. I advise beginners to frequently check their vehicle's position using the rearview mirror and make slight steering adjustments if they feel drifting. Exceeding the limit becomes even more hazardous in bad weather, so I personally supervise practice sessions to ensure my child masters this boundary. Safe driving starts with controlling every centimeter.