How is it safe to change lanes on a highway?

Principles of safe lane change: do not change lanes at once, do not change lanes when the front, back or sides of the vehicle are out of sight.
In a city where traffic flows upside down, changing lanes should be avoided and cautious. In addition to highways, this skill seems to be much simpler because the road is wide, the viewing angle is clear and there is no traffic jam, but even a small negligence is also expensive.

Characteristic when driving on the freeway is the cars passing each other at high speed, about 100 km / h. Therefore, this factor is both an advantage but also a danger. When changing lanes too quickly, the driver can cut off the cars behind or ram into the vehicle ahead as the video below, the consequences are unpredictable.

According to experienced drivers, to change lanes on a safe highway, drivers need to follow these steps:

Step 1: Consider the necessity

If there is no real need to change lanes, drivers should drive in a fixed lane on the freeway appropriate to the speed of the vehicle to minimize risk. If it is compulsory to change lanes to stop, pass the car, exit the freeway, continue with the following steps.

Step 2: Observe

Observe all directions around the vehicle, from the left, right, front, and rear through the vehicle's rear view mirrors, even turning around. Note that you only need to turn quickly when there is no vehicle approaching, because it only takes a few seconds to hit the rear of the car on the highway.

Step 3: Turn on the signal

After observing the directions a few times, find that the space is safe enough to change lanes, turn on the signal light, even if necessary to honk, to alert other vehicles that you need to change lanes.

Step 4: Observe again

After turning on the signal, the driver should look again to make sure there are no vehicles around, especially falling into the car's blind spot.

Step 5: Change lanes

Realizing the absolute safety, let the car change lanes decisively, keep the speed, do not slow down suddenly or brake after changing to the new lane.

Step 6: Steady lane

Once in the new lane, keep the speed suitable for other vehicles, turn off the lights, move and observe as you normally would. If the road has multiple lanes, repeat the steps from the beginning to the next lane change.