Road Network ofTokyo Metropolitan Government‫طﺮق طﻮﻛﯿﻮ‬About Tokyo Metropolitan
Government● Population: Approx. 13,784,000● Area: Approx. 2,193 km2● Total prefectural road network: 2,371 km(Asphalt: Approx. 91% Concrete: Approx.
4%)[Abu Dhabi][Tokyo]E139° 45′N35° 41′● Typical pavement structure: See the figure
below(design traffic volume of 3,000 vehicles/day,in one or more directions)
Dense-graded asphalt composition (Polymer Improved Type II)

Course-graded asphalt composition(Polymer Improved Type II)
Recycled course-graded asphaltcompositionConcretepavement

その他
OtherApprox. 91%

Recycled grain-adjusted crushed stone(RM-40)

Asphalt pavement
Recycled crusher run (RC-40)*The ratio between asphalt and concrete
estimated from a road surface property
survey result.

Environmental pavement implementation history
1995: Full-scale introduction of low-noise paving on prefectural roads
designated under “Act on Improvement of Areas Along TrunkRoads”
2005: Standardization and full-scale introduction of double-layer lownoise paving
2005: Started a full-scale implementation of water-retaining paving
2008: Started a full-scale implementation of heat-blocking paving
2014: Heat-blocking paving designated as an official heat control
measure for prefectural roads including those to be used for theTokyo 2020 Olympic and Paralympic Games marathon routes,
under the “Tokyo Metropolitan Government Long-term Vision”
2015: Heat-blocking paving installation started as a heat control
measure for prefectural roads including those to be used forTokyo 2020 Olympic and Paralympic Games marathon routes
TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Car Road Paving Policy ofTokyo Metropolitan Government‫ﻧﻈﺎم ﺗﻌﺒﯿﺪ طﺮق اﻟﺴﯿﺮ ﻓﻲ طﻮﻛﯿﻮ‬Diverse needs of various Tokyo residents including road
users and people living near main thoroughfares, etc.
Control-required areas

Applicable pavement types● Areas where road traffic noise control isrequired. Areas where road drainage
measure is required★ Low-noise (waterdraining) pavement

Additional functionality○ Areas where the road traffic noise levelexceeds the environmental threshold○ Areas where noise control is urgently required○ Newly constructed major roads○ Areas where road drainage measure isurgently required★ Double-layer low
noise pavement

MoreQuiet

Pavement with evengreater noise reductionfunctionality

Pavement with road surface
heat reduction functionality

Overall
Road surface
structure
Durability improvement● Areas prone to road flatness
impairment

Pavement with noise
reduction and rainwatersplashing reduction
functionality★ Water-retaining and/or
heat-blocking pavements● Areas where urban heat islandeffect control is required● Areas with heavy traffic where a
prolonged road surface repair isdifficult to accommodate

Quiet★ Long service life
pavement
Pavement with longterm durability *1★ Polymer-improvedasphalt pavement
Pavement with rutting
resistanceStandard pavement (dense-gradedasphalt pavement)
General areas other than the above

Dense-graded asphaltpavement (Commonpavement)*1. High-durability paving that does not require repairs
for a long period of time
TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Double-layer Low Noise Paving
for Noise Control‫ﺗﺪاﺑﯿﺮ اﻟﻀﻮﺿﺎء‬‫ﺗﻌﺒﯿﺪ اﻟﻄﺮق ﺑﻄﺒﻘﺘﯿﻦ ﺧﺎﻓﻀﺘﯿﻦ ﻟﻠﻀﻮﺿﺎء‬Dense-graded asphalt pavement(Common pavement)

Tire

Common low-noise pavement

Tire tread
patternnoise

Vibration
noise fromtire surface

Tire

Vibration
noise fromtire surface

Vibration
noise fromtire surface

Air trapped between tire tread
grooves and road surface

Noise reduction
with pavement
surface voids

Compression
Compression↓↓

Base layer

Expansion(explosion)

Base layer

Noise

Double-layer low noise pavement
Noise reduction
with pavement
surface voids

Tire

Fine-grain, high-void-ratio
pavement to reduce tiresurface vibration noise

Base layer

How a double-layer low noise pavement works
Two types of high void ratio (approx. 20%) porous asphalt compositions with different maximum grain
diameters are layered, with the finer-grain composition placed on top of the coarser-grain composition.
This provides greater noise reduction effect than that of normal low-noise pavement.
Double-layer low noise pavement has been applied to road sections where noise control is urgentlyrequired, including Ring Roads 7 and 8.

Parameter
Double-layer low noise
Performance pavement

Existing low-noise
pavement

Commonpavement

Surfacelayer

Upper layer: Smaller maximum
aggregate diameter of 5 mm
Air void ratio of 18% to 25%
Lower layer: Larger maximum
aggregate diameter of 13 mm
Air void ratio of 16% to 22%

Maximum
aggregate
diameter: 13 mm

Maximum
aggregate
diameter: 13 mm

Air void ratio:
16% to 22%Air void ratio:
3% to 6%

86 dB

89 dB

96 dB

Tire noise* Tire noise measured according to the procedure described in “Paving Performance Evaluation
Method” (issued by Japan Road Association).
* Tire noise measured as part of the Tokyo Metropolitan Government trial paving projectTOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Water-retaining Pavingfor Heat Control‫ﺗﺪاﺑﯿﺮ اﻟﺤﺮارة‬‫ﺗﻌﺒﯿﺪ اﻟﻄﺮق اﻟﺤﺎﻓﻈﺔ ﻟﻠﻤﺎء‬Water-retaining
pavement mechanism
SunlightRain

Evaporation

Water retention

Tokyo-type waterretaining pavement

The upper layer offers noise
reduction effect while thelower layer provides roadsurface heat reduction
effect.

Water retention

Pavement(surfacelayer)

Air void region (25 mm)

Water-retaining region(75 mm)Water-retaining pavement
Water-retaining material, injected into the voids in the pavement, absorbs and retains rainwater andother incoming water. The heat of vaporization of this retained water when it evaporates under sunlight
reduces road surface heat so that less heat is radiated from the pavement into the atmosphere.

Performance requirements
Parameter
Road surface heatreduction
Waterretaining
pavement

Immediately after roadcompletionIndoor irradiation test result:Heat reduced by 4oC or greater

Water retention capacity

Measured after submerged underwater for 24 hours
5.0 kg/m2 or greater

Road surface skidresistancePendulum-type skid resistance tester
60 BPN or greater

Water penetration
through the road surface

On-site permeation test
500 ml/15 s or greater

TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Heat and Urban Heat Island
Effect in Tokyo‫ظﺎھﺮة اﻟﺠﺰر اﻟﺤﺮارﻳﺔ اﻟﺤﻀﺮﻳﺔ واﻟﺤﺮارة ﻓﻲ طﻮﻛﯿﻮ‬Urban heat island effect in Tokyo・Tokyo's temperatures are rising・Temperatures are especially high in central Tokyo
・Necessary to comprehensively advance measures including heat island countermeasures toimprove Tokyo's thermal environment

central area

Tokyo

Source: Handbook to Summer Heat Control” (issued by
Bureau of Environment, Tokyo Metropolitan Government)

Source: Handbook to Summer Heat Control” (issued by
Bureau of Environment, Tokyo Metropolitan Government)

Annual average temperature deviations forTokyo, Japan, and the world

Distribution of average daily lows (℃)(July 1, 2013 - September 30, 2013)

Heat-causing factors andtheir effects

Heat control principles

Heat-causing factors in urban areas can beclassified into the following two types:○ Heat emission from air conditioners andcars○ Heat retention in buildings and the groundIn addition to the above, people are affectedby heat (heatstroke) as a result of:● Heat reception from sunlight and also fromthe above-described heat sources

To alleviate heat in an urban area, it isimportant to make effort:○ not to emit heat by reducing energy
usage.
○ not to retain heat by improving thebuilding surface and the ground byhaving greenery, using water andemploying other assisting technologies.
In addition to the above, to alleviate heat
impact on people, make effort:● not to receive heat by using sunshades,or spraying dry (fine) mist
Does not emit heat
Does not retain heat

Retains heat

Does not retain heat

Emits heat

Does not receive
heat

Receives
heat
Emits heat

Retains heat

Source: “Handbook to Summer Heat Control” (issued by
Bureau of Environment, Tokyo Metropolitan Government)

TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Does not receiveheat

Does not retain heat

Source: “Handbook to Summer Heat Control” (issued by
Bureau of Environment, Tokyo Metropolitan Government)

Heat Control Principlesand Techniques‫طﺮﻳﻘﺔ اﻟﺘﻔﻜﯿﺮ ﻓﻲ ﺗﺪاﺑﯿﺮ اﻟﺤﺮارة وﺗﻘﻨﯿﺘﮫﺎ‬Does not retain heat
Does not emit
heat
Does not retain
heat

Does not retain
heat

Does not receive
heat

Does not receive
heat

Does not retain
heat

Source: “Handbook to Summer Heat Control” (issued by
Bureau of Environment, Tokyo Metropolitan Government)

Does notemit heat
Energy saving, reductionof exhaust heat, etc.

Heat insulation

Does notreceive heat

Does notretain heat

Plant trees alongstreets, etc. tohave groundgreeneryHeat-blocking &water-retaining
road surface
designRooftop andwall greenery
Heat-blocking building
design Note 1
Retroreflective surface tobounce heat backShade over the windows

SunshadeWatersprinkling

Heat-blocking & waterretaining road surface
designSidewallcooling

Dry (fine)mist

Source: “Handbook to Summer Heat Control” (issued by Bureauof Environment, Tokyo Metropolitan Government)

Note 1: Heat-blocking buildings may potentially become a heat emission source in wintertime(by increasing the amount of exhaust heat).
*This document should not be considered as an evidence to validate the heat-blocking andwater retention effects on the urban heat island effect.
TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Solar Heat-Blocking
Pavement‫ﺗﻌﺒﯿﺪ اﻟﻄﺮق اﻟﻤﺎﻧﻊ ﻟﺤﺮارة اﻟﺸﻤﺲ‬Project Area

Tokyo

TOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html

Solar Heat-Blocking
Pavement‫ﺗﻌﺒﯿﺪ اﻟﻄﺮق اﻟﻤﺎﻧﻊ ﻟﺤﺮارة اﻟﺸﻤﺲ‬ndTOKYO METROPOLITAN GOVERNMENT
http://www.metro.tokyo.jp/english/index.html