T/CACEM 25-2023 in English

本文件规定了高速公路限速标志的设置要求，包括固定限速标志、可变限速标志、建议速度标志、限速标志解除，以及与限速标志配套使用的速度控制设施的设置等。
本文件适用于新建和改扩建高速公路限速标志的设置，以及在役高速公路限速标志的设置或调整。

Scope

Basic requirements

5 Speed limit sign setting methods
5.1 Where the highway sections have similar basic conditions, it is advisable to adopt the same speed limit sign setting method. For special speed limits due to frequent traffic accidents, specific weather impacts or roadside hazards, it should be set based on safety evaluation results. When appropriate, variable speed limit signs or recommended speed signs are advisable.

5.2 The setting methods of highway speed limit signs include single-speed limits, differentiated speed limits for vehicle types, lane-specific speed limits, and a combination of lane differentiation and vehicle type differentiation. Depending on the different conditions of speed limit sections and variations in traffic operation status, these can be selected as needed with large vehicles right-side markers.

5.3 When using differentiated speed limits or combined lane and differentiated vehicle type settings for highway speed limit signs, auxiliary signs should be used to complement them. The use of auxiliary signs should comply with the provisions of GB 5768.2-2017 "Traffic Signs and Road Markings - Part 2: Traffic Signs" and JTG D82-2017 "Specifications for Traffic Signs and Pavement Markings".

5.4 The panel of highway speed limit signs should comply with the following regulations.

5.5 The supporting form of highway speed limit signs can be selected in the following ways.

6 Fixed speed limit sign setting
6.1 Fixed speed limit signs should be placed at the starting point of a highway section where fixed speed limits apply, and they may be repeated based on the situation.
6.2 Where the main line, deceleration lanes, or sections with restricted operational speeds are set in interchanges of highways, the difference in their speed limits should not exceed 30 km/h. Otherwise, transitional speed limit zones and stepwise speed limit signs should be installed.
6.3 For fixed speed limit signs related to tunnel speed limits, they are advisable to be placed at an appropriate location about 100-200 meters before the tunnel entrance. They may also be combined with height limit signs as needed. For continuous tunnel sections, the entire tunnel section can be treated as a single speed limit zone.
6.4 For fixed speed limit signs related to special bridge speed limits, they are advisable to be placed at an appropriate location about 0-200 meters before the bridge head.
6.5 For highways requiring speed monitoring for law enforcement, it is advisable to set up fixed speed limit signs within 500 meters of the speed detection equipment. They may also be used in combination with预告标志(advance warning signs)as needed.
6.6 Fixed speed limit signs for highway toll lanes should be attached where necessary on safety islands.

7 Variable speed limit sign setting
7.1 It is advisable to set variable speed limit signs based on weather visibility, lighting conditions, road surface wetness, traffic efficiency, vehicle operation safety, emergency event handling, and operational management requirements.
7.2 The character form and color of the variable speed limit sign should comply with the relevant provisions of GB 5768.2-2017 "Traffic Signs and Road Markings - Part 2: Traffic Signs". The panel is recommended to be a variable speed limit sign using LED as the light source, its shape, size, main technical indicators, etc., should meet the provisions of JT 432-2018 "Technical Conditions for Highway LED Variable Speed Limit Sign".

7.3 When certain sections of a highway meet any one of the following conditions, it is advisable to set up variable speed limit signs.
7.4 It is recommended to separate setting of variable and fixed speed limit signs on the same section. They should not be simultaneously displayed.

7.5 If there are inconsistencies between fixed and variable speed limit signs, the variable speed limit sign's value shall prevail.

8 Recommended speed sign setting
8.1 Where geometric line conditions restrict highway operations, speeds are less than the basic speed limits of adjacent sections, and the length is relatively short with no safety issues for other vehicles, recommended speed signs may be set as per JTG D82-2017 "Specifications for Traffic Signs and Pavement Markings".

8.2 In cases where adverse weather conditions such as rain, snow, or fog frequently occur and significantly impact traffic safety when they do happen, recommended speed signs may also be set.

8.3 For some special sections within general speed limit areas of highways, lower than the maximum speed limit value recommended speed signs can be set based on actual conditions.
8.4 Recommended speed signs for highway toll lanes can also be installed as needed.
8.5 Highway sections with recommended speed signs should not display fixed speed limit signs at the same or nearby locations.

9 Removal of speed limit signs
9.1 There are two ways to remove restricted speeds on highways: setting a sign indicating the removal of restrictions, or installing new signs displaying different restriction values.
9.2 Speed limit removal signs should be placed at the end of highway sections where speed limits apply and should preferably stand alone, with a new speed limit sign set up after them.
9.3 When a new speed limit sign with a different value indicates the end of a previous section, there is no need to install a separate speed limit removal sign.

10 Related speed control facility settings