Is the dual trailer a compliant vehicle?

Trailer is a major model in the logistics transportation industry, such as semi-trailer, full trailer, mid-axle trailer, etc. At present, the most widely used in China is semi-trailer, which is composed of tractor and a semi-trailer. With the continuous improvement of vehicle technology, more and more new models are widely used, such as double-trailer.

At first mention of this title, it seems to have a slightly unintelligible meaning. A double-trailer, whose technical name is a double-trailer train, pulls two standard semitrailers in succession behind a standard tractor, or pulls a standard semitrailer and a mid-axle carriage. Among them, the tail of a semi trailer in front of the corresponding transformation, used for pulling the back of the semi carriage or middle axle carriage.

After seeing the picture, many people said: how does this model look familiar? Isn't that the same car that was secretly modified?

Good, early on the relevant laws and regulations on vehicles are not too perfect, privately modified models of the situation is more common, this similar to the double-trailer models did appear, but the laws and regulations can never admit its legality, let the traffic police catch, fine points but not to discuss.

It is understood that this kind of double trailer is used in many countries, in Sweden, Finland, the Netherlands, Spain and other countries, the standard connection mode for tractor +13.6 meters standard trailer + trailer connection platform +13.6 meters standard trailer, the total weight is not more than 72t, a total of 11 axles, full load under the condition of the average axle load in 6.5t. The average axle load is about 1.5 tons less than that of an average semi-trailer with a total weight of 40 tons.

On the contrary, users' pursuit of transportation loading and timeliness has been improved in recent years, resulting in the frequent occurrence of super large and long vehicles in the transportation market, which does not conform to the requirements of laws and regulations and is difficult to achieve standardized management, which is not conducive to traffic safety. However, the double-trailer has not been used since GB1589 stipulates that the maximum total mass of a vehicle is 49 tons, the maximum total length of a vehicle is 16.5 meters, and the total length of a car and train is 22 meters.

Compared with ordinary trailer models, what are the advantages of dual trailer?

1. Compared with the ordinary pull and hang combination, the transport volume of double trailer can be increased by 50%, and the average transport unit cost of all kinds of comprehensive cargo combination can be reduced by about 34%, which greatly improves the transport efficiency;

2. By using the transport mode of dual-trailer, road transport can reduce the unit fuel consumption of transport goods by 10%, and also reduce the transport cost, and the road space can be released to a certain extent;

3. In addition to commercial benefits, double-trailer also brings significant environmental and social benefits, which can help reduce carbon dioxide emissions, reduce road surface wear and alleviate driver shortage.

Although double-trailer has obvious advantages in transportation, it also has many shortcomings or shortcomings:

1. Excessive total mass brings additional danger. Needless to say, the body is too long, the weight is too large, the driving difficulty is increased, and the lethality is not to be underestimated. It is also because of this that the vehicles involved in the dual trailer transport abroad must be installed with hydraulic retarder, whole vehicle suspension, disc brake, and must be equipped with perfect mechanical and electronic auxiliary systems, such as blind spot monitoring, adaptive cruise, electronic stability system, etc.

2. Transport roads are restricted. After all, the vast majority of highway entrances or roundabouts and curves cannot meet the transport needs of double-trailer vehicles, and vehicles may face the problem of difficult steering. In addition, many service areas or gas stations are unable to provide ultra-long parking Spaces, so double-trailer vehicles may have to be unhung and parked separately if they want to park, which affects the transportation efficiency.

3, the driving difficulty is too high, compared with the ordinary semi-trailer, the driving difficulty of double trailer is greater, so the requirements for double trailer drivers in foreign countries are also very strict, must have 5 years of truck driving age, three consecutive years without accidents, driving must be trained. In addition, when driving a double-trailer, overtaking is prohibited at all times and driving in heavy rain and snow is prohibited. The length of the vehicle must be marked on the rear of the vehicle, and reflective strips and signs must be installed.

However, according to insiders, the dual-trailer plan to realize demonstration application in some parts of China during the "14th Five-Year Plan" is mainly based on four considerations:

1. Road transport has a large volume and heavy tasks of energy conservation and emission reduction. At present, the freight volume of road transportation accounts for more than 70% of the comprehensive transportation system. Coupled with the continuous development of the express industry, the demand for large-volume transportation models is growing day by day. In addition, the pressure of energy conservation and emission reduction is huge, and it is still a long way to go to achieve the goal of "dual carbon".

2. Non-standard models are eliminated, and replacement models need to be supplemented. At present, the relevant departments are strengthening the governance of non-standard models, and the transport industry urgently needs to supplement and replace models, so as to alleviate the actual demand of the industry for large-capacity transport.

3. The technology and experience of international double-trailer use are rich enough to provide a good reference experience and learning basis for domestic research;

4. At present, our country has become a party to the United Nations "Convention on the International Transport of Goods TIR Certificate Customs", promoting the facilitation of our international road transport at the same time, but also promoting the domestic models and international models, the perfection of our road transport vehicle type is imminent.

It can be seen that it will take some time for the dual trailer to be applied in China. Perhaps it will become a legal model on the road in the near future. According to the relevant experience in foreign countries, the dual trailer installation disc brake and air suspension may become standard. DARO Heavy Industry Group is one of the enterprises with an early start in mass production of "one-piece" axles in China. Founded in 2001, it focuses on the research and development and production of various trailer axles and accessories. In 2018, the disc axles of DARO independently developed and produced and successfully entered the market, using lightweight materials and integrated alloy brake discs. With locally strengthened square shaft beam and trailer special bearings and other accessories, improve the bearing capacity, successfully reduce the trailer axle weight, full fuel saving and efficiency.