GENARAL INFORMATION

Guardrails or barriers, which are a part of traffic safety in road transportation that is widely used in our country, are produced from steel, wood, plastic, concrete materials or as hybrid namely as a combined use of these materials. Concrete barriers are divided into two types by the production method as prefabricated or on-site casting. Concrete barriers produced by both methods can be used on the roads upon obtaining the CE certificate after the collision tests specified in the EN 1317-2 standard.

Concrete barriers were first used in the 1950s in the United States and in the 1970s in the Europe.

Road transportation in our country is used more than railway, sea and air transportation.

 

22 people are killed while 842 people are injured and 60 people are disabled due to traffic accidents that occur every day in Turkey. 20% of the total traffic accidents are caused by the vehicles crossing into the opposite lane after the crash and this situation increases the mortality rates significantly. There is a legal obligation to use standardized concrete barriers in the medians of high standard roads in a number of countries, especially in Ireland and the UK, due to their advantages and the fact that they prevent the vehicles from crossing into the opposite lane.

There are differences between the performances of steel or steel rope barriers and concrete barriers, which are used all over the world as an alternative to each other. In particular, prefabricated concrete barriers absorb the collision energy stretching like a train car after the crash and keep the vehicle on the road. Concrete barriers prevent secondary accidents by preventing the vehicle from crossing into the opposite direction during an accident. Moreover, sharp and pointed edges do not cause serious deformation in concrete barriers during collision and therefore post-accident injuries are minimized. In addition to their high security, concrete barriers are long-lasting and do not require frequent maintenance/repair.

In order to reduce the number of accidents and prevent the material and moral losses, it is also of great importance to place safety barriers on the roads, where required, as well as making vehicles safer by means of research and development studies and  enforcing the laws in a more effective manner.

In our country, the use of concrete barriers is increasing day by day with the recognition of their high security and economic advantages.

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Situation Assessment of the Noise Barriers in Turkey

As is the case for our country, as a result of the rapid changes in the developing countries; the noise emerging from unplanned and inter-bedded development of the housing and industry areas, uncontrollable population and increases in traffic density in parallel to this, has become an environmental issue with psychological and physiological impacts on human health.  

First step in managing noise is to correctly identify the exposure level. For this purposes, strategic noise maps are drawn to make an assessment considering all sources and physical environmental factors within a certain area.  

Noise maps are followed by identifying the hot spots in terms of environmental noise and then noise action plans that include technical measures for developing noise reduction scenarios are prepared.   

Technical measures adopted for prevention/reduction of noise can be grouped under three main headings;   

Noise Measures at the Source;

To eliminate unnecessary sources to reduce noise at the source and reduce the noise levels of the noise sources, 

At Micro Scale; inspection of the noise sources at the industrial and entertainment facilities is the domain of the manufacturers and design engineers, 

At Macro Scale; inspection of noise sources such as airport, railway and highway is within the area of responsibility of the experts in the field such as engineer, architecture and city planners.  

Noise measures between the Receiver-Source;

Highway/railway barriers are used to prevent the noise between the receiver-source. The noise between the receiver-source is basically affected by the distance between the source and the receiver and elements within the area between the source and the receiver.  From this point of view, it is important that the issue is analyzed at the macro scale and city planners make their designs considering noise inspection.

Noise measures at the receiver;

Activities carried out to prevent noise at the receiver generally include building facade insulation. For the noise that cannot be inspected at the source and between the source and the receiver and reach the buildings, measures that can be adopted at the micro scale can be discussed. For example designs reducing the noise can be preferred at the building envelope or window systems. Architects may play an active role for the measures such as designing the structures in a more noise-proof manner, developing the design considering the direction of the noise.

Actions to be taken before noise reduction implementations 

Before the measures to be taken to prevent the noise problem emerging on the highways and railway network, noise maps regarding the noise levels and sources should be prepared. The most affected settlement areas and the number of schools, hospitals, residences at the settlement areas should be identified on these maps and their locations are determined.  

Noise Action Plans, which identify the actions to be taken to reduce the noise levels or to fully prevent the noise based on the noise maps, are prepared. Hot spots, sensitive areas in other words, are identified in the Noise Action Plan using the population factor and excess value. Afterwards how much noise reduction is required at the regions with these hot spots (location and kilometer on the road network) is identified.    

Determinations: 

Determinations regarding production 
In our country, there is no domestic manufacturer, whose products have the certificates that meet all EN standard frameworks. However, there are firms that manufacture at the European Union and distribute in Turkey. Acoustic tests within the scope of the aforementioned standards are carried out by the Turkish Standards Institute and partially by the National Metrology Institute.  

Determinations regarding the legislation 
Studies should be carried out on the requests regarding the legislation requests for the promotion of the certified products, which are domestic and have international validity, by being engaged in the necessary talks with the Ministry of Environment and Urbanization, General Directorate of Environmental Management. 

Identifying the potential in our country and implementations to be carried out 
The source inventories, which are necessary for the preparation of the noise maps of 59 provinces in Turkey, have been prepared and  strategic noise map for 39 out of these have been completed by TUBITAK MAM.  Noise maps of other 20 provinces will be completed until the end of 2019. Also, noise action plan studies for 6 provinces have started and source-based (highway, railway, industry, entertainment facilities) noise reduction scenarios have been developed within 3 provinces and feasible technical measures have been acoustically projected. Similar studies continue for other 3 provinces.  

TUBITAK MAM started to carry out studies on developing barrier systems with the domestic materials, which comply with the international standards, together with the IMSAD members. Although concrete steps have not been taken yet, the foundations for collaboration with the firms that wish to carry out studies regarding this subject are being evaluated. Within this context, use of concrete, which is a long-lasting, durable, maintenance and repair free, solid and sustainable material, in the construction of noise barriers is being evaluated with care. The concrete stands out with the property of being poured according to different designs and workability and usability in a composite manner with different materials that are suitable in terms of engineering properties. The most competent project team to carry out the acoustic design and field works for the development of barrier systems in the country continue their works under the roof of TUBITAK MAM Environment and Cleaner Production Institute. The laboratory infrastructure is available at TUBITAK MAM ECP institute, which has accreditation certificates for product development regarding the identification of the acoustic conformity of the products of the manufacturer firms, also acoustic projecting of the products usable in the system and conducting the field performance tests.

MOTORCYCLIST PROTECTION SYSTEMS

The studies in a number of countries in the Europe, the UK and Ireland being in the first place, prove that existing steel barrier systems do not ensure the security of the motorcyclists, on the contrary they lead to a life-threatening situation for the motorcyclists. Existing steel barrier systems cannot prevent the motorcyclist from sliding under the barrier during collision; they can cause them to lose their lives or their limbs cutting the motorcyclist like a guillotine because of their sharp and sharp edges. In addition, crashing into the posts of steel barrier systems and these posts being stuck onto the motorcyclist causes the motorcyclists to lose their lives.

According to research, a motorcyclist, who crashes into the barrier, is seven times more likely to die than a vehicle driver. In addition, it is found out during the researches that motorcyclists are 29 times more likely to be involved in a fatal barrier accident than the vehicle drivers based on the ratio of travel distance.

Concrete barriers are the barriers that are especially used in the divided roads with high speed limit in the world. Use of concrete barrier as per the EN 1317 standard is legally mandatory at the divided roads in a number of countries, Ireland and the UK being in the first place. Concrete barriers have a continuous flat surface and block the motorcyclist from slipping under the barrier during collision. They absorb the collision energy and spread it into a wide area and return the motorcyclist back to his/her lane. It is identified during the investigations of 951 motorcycle accidents in the USA that the possibility of being severely injured is 1.4 times higher for steel barriers compared to concrete barriers even the motorcyclist wears a helmet. Similarly, in a study carried out by the USA road authorities, it is found out that use of concrete barriers instead of steel barriers reduces death risk by 36% for the motorcyclists. 

Concrete barriers, which absorb the collision energy and do not cause sharp and pointed edges during collision, prevent motorcyclists from sliding under the barrier and maximize the safety of the motorcyclists.