A speed limit ahead sign indicates that within the section of road from this sign to the next sign indicating the end of the speed limit or another sign with a different speed limit, the speed of motor vehicles (in km/h) must not exceed the value shown on the sign. Speed limit signs are placed at the beginning of the section of road where speed restrictions are required, and the speed limit should not be lower than 20 km/h.
Purpose of Speed Limits:
Motor vehicles must not exceed the maximum speed limit indicated by the speed limit ahead sign. On road sections without speed limit ahead signs, a safe speed should be maintained.
Driving at night, on road sections prone to accidents, or in weather conditions such as sandstorms, hail, rain, snow, fog, or icy conditions, speeds should be reduced.
Speeding is a common cause of traffic accidents. The purpose of highway speed limits is to regulate vehicle speeds, reduce speed differences between vehicles, and ensure driving safety. It is a method that sacrifices efficiency for safety, but it is also one of the more important safety measures among many traffic management measures.
Determination of Speed Limits:
Observations suggest that using the operating speed as the speed limit is reasonable for general road sections, while the design speed can be used as the speed limit for special road sections. Speed limits must comply with those explicitly stipulated by traffic laws and regulations. For highways with overly complex traffic conditions or accident-prone sections, speed limits lower than the design speed may be selected based on traffic safety analysis. The difference in speed limits between adjacent road sections should not exceed 20 km/h.
Regarding the setting of speed limit ahead signs, the following should be noted:
① For road sections where the characteristics of the highway or the surrounding environment have undergone significant changes, the speed limit ahead signs should be reassessed.
② Speed limits should generally be multiples of 10. Limiting speed is essentially a management action; the decision-making process requires weighing and judging the importance of safety, efficiency, and other factors, as well as the feasibility of implementation. The final determined speed limit reflects the wishes of the government and the public.
Because different speed limit setting agencies consider different weights of factors affecting speed limits, or use different technical verification methods, different speed limit values may sometimes occur. Therefore, there is no “correct” speed limit; only a reasonable speed limit acceptable to the government, management units, and the public. Speed limit signs must be installed after approval by the competent authority.
Common Speed Limit Sections:
1. Appropriate locations after the acceleration lane at the entrance of expressways and Class I highways;
2. Sections where traffic accidents frequently occur due to excessive speed;
3. Sharp curves, sections with limited visibility, sections with poor road conditions (including road damage, water accumulation, slipperiness, etc.), long steep slopes, and dangerous roadside sections;
4. Sections with significant lateral interference from non-motorized vehicles and livestock;
5. Sections significantly affected by special weather conditions;
6. Sections of highways at all levels where the technical indicators are controlled by the design speed, sections with speeds lower than the limits specified in the design specifications, sections with insufficient visibility, and sections passing through villages, towns, schools, markets, and other areas with high pedestrian traffic.
Speed Limit Ahead Sign Positioning:
1. Speed limit ahead signs may be placed multiple times at the entrances and intersections of expressways, Class I highways serving as trunk lines, urban expressways, and other locations where drivers must be reminded.
2. Speed limit ahead signs should preferably be installed separately. Other than minimum speed limit ahead signs and auxiliary signs, no other signs should be attached to the speed limit ahead sign post.
3. Area speed limit signs should face vehicles approaching the area and be placed in a prominent location before entering the speed-restricted area.
4. Area speed limit end signs should face vehicles leaving the area, making them easily visible.
5. The speed limit difference between the main line and highway ramps and urban expressways should not be more than 30 km/h. If the length allows, a tiered speed limit strategy should be used.
Post time: Nov-25-2025
