Research Trends and Results

Clarifying the future roadside environmental load
reduction effects of the penetration of next-generation
vehiclesKADOYU Katsunori, Head
OGAWA Tomohiro, Senior Researcher
NAGAHAMA Yosuke, Researcher
Road Environment Division, Road Department(Key words) Next-generation vehicles, carbon dioxide, roadside environmental load
1. Introduction
Cargo vehicles produce 34% of all CO2 emissions
from the transport sector1), and it is important tointroduce cargo vehicle environmental loadcountermeasures. This research trial calculated thefuture roadside environmental load reduction effectsof the penetration of next-generation vehicles.

Figure 1. Trial Calculation Procedure
Survey of ordinary traffic volume by the 2010 road census (estimated future volume)
Traffic volume by section, by vehicle type, by inbound/outbound,
By section, by section lengthand by time period
Q-V formula
Traveling speed by section, by inbound/outbound, bytime period

CO2 emission factor

2. Trial calculation conditions
The table presents an outline of the trial calculation
conditions. In addition, traffic volume, traveling speed,
next-generation vehicle penetration rate and CO2
emission factor were set with reference to sourcedocuments2)3)4)5)6)7).

4. Summary
The trial calculation clearly shows that even amongcargo vehicles, it is important to promote measures tospread the use of next generation vehicles as heavyvehicles in particular.
Table. Outline of Trial Calculation Conditions
Items

Settings

Object of calculation Carbon dioxide (CO2)
Calculation period

2010, 2020, 2030, 2040, 2050

Calculation range

Sections where normal traffic volumes are surveyed during the roadtraffic census

Next-generation
Hybrid vehicles, plug-in hybrid vehicles, electric vehicles, fuel cellvehicles considered vehicles, clean diesel vehicles, gasoline vehicles
Zero: (penetration rate same as in 2010)
Level of penetration
Low: (case where penetration rate is estimated as low)of next-generation
Medium: (average penetration rate)
vehiclesHigh: (case where penetration rate is estimated as high)CO2 emission factor by section, byinbound/outbound, by time period

CO2 emissions by section, by inbound/outbound, by vehicle type, and by time period
Totaled by section, inbound/outbound,vehicle type and time period

Total CO2 emissions in the ordinary traffic survey sections of the road traffic census

Figure 2. Trial Calculation of CO2 Emissions(Penetration level: high)200,000
CO2 emissions (1,000t-CO2/year)

3. Trial calculation results
As a result of the trial calculation of CO2 emissions
by the procedure shown in Figure 1, the CO2
emissions in 2050 were calculated as 45% lower thanin 2010. At this time, CO2 emissions by small-sized
vehicles and heavy vehicles are almost equal, but
because the penetration rate of large next-generation
vehicles will be lower than that of small-sized
next-generation vehicles, the trial calculation revealed
that in 2050, heavy vehicles will emit between 60%
and 70% of all CO2 (Fig. 2).

Vehicle-kilometers traveled by section, byinbound/outbound, by time period

Heavyvehicles
大型車

Small-sized

小型車vehicles

150,000

100,000

50,00002010

2020

2030

2040

2050

[Sources]
1) Ministry of Land, Infrastructure, Transport and Tourism web site: Carbon
dioxide emissions by the transport sector, http://www.mlit.go.jp/2) Ministry of Land, Infrastructure, Transport and Tourism, Study Committee
on Future Traffic Demand Estimation on Roads: Estimation of future traffic
demand, 2008
3) Central Environment Council: Report on countermeasures and policies
beginning in 2013, 20124) M. Dohi et. al.: TECHNICAL NOTE of NILIM, No. 671, Grounds for thecalculation of the automobile emission coefficient used to evaluate roadenvironment impacts, etc. (2010 Edition), 20125) K. Matsuhashi, Measures to achieve medium to long term sharp reductionof CO2 emissions in the transport sector, Global Environment, 12, pp. 179 –189, 2007
6) Next-generation Vehicle Penetration Strategy Committee: Next-generation
vehicle penetration strategy, 20097) Metropolitan Tokyo: Automobile Management Plan Preparation Handbook,2011