icon of Environmental InitiativesEnvironmental Initiatives

01. Initiatives to Improve the Roadside Environment

Noise and vibration countermeasures

The Metropolitan Expressway has various measures in place to alleviate roadside noise.
In addition to adopting an "advanced and improved noise barrier" effective in reducing the sound which goes over the top of the barrier by attaching cylinder-shaped sound absorbing material to the top of the noise barrier, we reduce street noise that reverberates against the underside of the elevated bridge by installing "underside noise absorption boards" on the bottom (underside) of the elevated bridge.
Furthermore, we adopted "high performance pavement" designed with more gaps than ordinary pavement for paving roads, to suppress the noise from compressed air produced between the tires and road surface. The many gaps in the multi-function pavement also assist in drainage during the rainy season, contribute to improving driving safety on rainy days by preventing splashing and hydroplaning, reduce headlight reflection on roads, and improve lane mark visibility, etc.
In addition, noise and vibration are strongly affected by road flatness and vehicle weight. Therefore, to deal with the structure itself, we promote solutions such as repairing roads, renovating joints, eliminating joints, etc., as well as cracking down on vehicle weight violations that accelerate aging of the structures.

Advanced and improved noise barrier

Advanced and improved noise barrier

Advanced and improved noise barrier

Advanced and improved noise barrier

Rear noise absorption boards for underside of elevated expressway

Rear noise absorption boards for underside of elevated expressway

High performance pavement

High performance pavement

High performance pavement

High performance pavement

Joint elimination

Eliminating road joints enables smooth driving without shocks. Reduces noise and vibration. After the work, joint replacement becomes unnecessary, so traffic congestion due to repair work is reduced.

Image of before the no-joint construction work
Image of after the no-joint construction work

Sound-proof work subsidy system

The system partially subsidizes the expenses needed for soundproofing work for people who deal with traffic noise above a certain level at their residence, even after possible road structure measures have been implemented.

  • *For those who live in the area before the highway was opened for service.
  • *As a rule, those who have already received a subsidy are not eligible.
  • *Housing that is already outfitted with traffic noise protection is not eligible.
Image of sound proof construction subsidy system

Improvements in air pollution

When traveling at a speed of 60km/h, emissions per 1km of the automobile exhaust gases such as carbon dioxide (CO2), nitrogen oxide (NOx), and suspended particulate matter (SPM) are at a minimum. Driving at a constant speed also improves fuel economy.

Promotion of road network maintenance/bottleneck solutions and improvement in environment

In order to maximize the network functions of the Central Circular Route in response to continued traffic congestion in the inner-city area, we will continue to take measures against bottlenecks such as adding lanes, and continue further network expansion of the Yokohama Circular Route and other routes.

Image of the areas of road network maintenance and bottleneck measures

Equipment for removing discharged components

SPM removal equipment and low concentration denitrification equipment are installed at ventilation stations along the Central Circular Route (Yamate Tunnel), Kanagawa Route 6 Kawasaki Line (Daishi Tunnel), and Yokohama North Route (Yokohama North Tunnel). SPM removal equipment can remove more than 80% of suspended particulate matter (SPM)*. Also, low concentration denitrification equipment can remove more than 90% of nitrogen dioxide (NO2). With these two mechanisms, the impact of exhaust gases from the ventilator is reduced to less than one hundredth of the environmental standard.

  • *Suspended particulate matter (SPM) is very small particulate matter (particle size of 10μm (micrometer) or less) contained in exhaust gas etc.
Image of the explanation of equipment for removing discharged components

Measures against obstacles caused by highway construction

The Metropolitan Expressway is composed of various structures, and construction of these structures may cause inconvenience to residents in the vicinity. The Metropolitan Expressway has a system for covering necessary expenses for "television signal reception interference" and "blocked sunlight".

Measures to prevent television signal reception interference

The system covers the necessary costs to eliminate interference caused by new Metropolitan Expressway construction for persons experiencing radio wave interference above a certain level for their televisions.

  • *Applicants who applied within one year after completion of highway construction are eligible.
  • *If your application has been accepted, no new applications will be accepted unless there is a new reason such as construction or renovation along the highway.
Image of the measures against television wave reception disorder

Measures for blocked sunlight

The system covers the necessary costs for new burdens in living caused by new Metropolitan Expressway construction for persons experiencing shadows above a certain level at their residence.

  • *Applicants who applied within one year after completion of highway construction are eligible.
  • *If your application has been accepted, no new applications will be accepted unless there is a new reason such as construction or renovation along the highway.
Image of anti-sun protection measures