Generally speaking, only those who stay for more than 4 hours are identified as risk areas. Just passing by, the train stops and driving, these health codes will not change color, but the itinerary will show that you may have been to high-risk areas, but it does not mean that you have been to medium-high-risk areas. As long as the health code is not a high-risk area, there is no problem. Travel cards may accumulate for nearly 14 days in high-risk areas within the regional administrative area, and the area will be automatically recorded and marked in red. In this case, the local epidemic prevention department may let you register, and then you can go. If you need to do nucleic acid testing, call after call, those who are negative and come from low-risk areas in China are usually not isolated.