●Research Trends and Results

Verification of the superiority ofmotorcycles as a road traffic mode
kind to the global environment
SONE Shinri, HeadDOHI Manabu, Senior Researcher
Environment Department, Road Environment Division(Key words) Global warming, carbon dioxide emissions, motorcycles

2. Comparative survey of carbon dioxide emissions from
4-wheel vehicles, motorcycles and electric scooters

In order to confirm that motorcycles and electricscooters are road transport modes kinder to the global
environment than 4-wheel vehicles, a comparative
survey of carbon dioxide emitted by these vehicles
during actual driving was performed. The survey wascarried out in Tokyo in the daytime for a total of 12hours—3 hours per day on three weekdays from
September 27 to 29, 2011—on an ordinary road whichis always congested (9.2km from Yoyogi Park toHibiya Park). The vehicles used for the survey were a4-wheel vehicle, motorcycles (250cc, 125cc, 50cc)
and an electric scooter (equivalent to 50cc). The
vehicles selected had average vehicle specifications
for vehicles in each class. The carbon dioxideemissions were converted from the quantities of fuelconsumed and electric power consumed. The quantityof fuel consumed was obtained by measuring theactual quantity of oil supplied while the quantity ofelectric power was determined by measuring thequantity charged after driving.

3. Outline of the survey results
Figure 1 shows the relationship between travelingspeed and carbon dioxide emissions based on theresult, while Table 1 shows the average travelingspeed and carbon dioxide emissions by vehicle type.
The survey revealed the following trends.
1. Carbon dioxide emissions decline in the order:
4-wheel vehicle (air-conditioning on), 4-wheelvehicle (air-conditioning off), motorcycles, andelectric scooters.
2. Average traveling speed in the congested section
was higher for the motorcycles (250cc, and 125cc)
than the 4-wheel vehicles.
3. The carbon dioxide emitted by all vehicles
decreased as the average traveling speed increased.
In the future, the synergistic effects of the two
superior aspects of motorcycles (lower carbon dioxide
emissions, greater traveling speed during congestion)
will be analyzed.
350

CO2 Emissions (gco2/km)

1. Introduction
The carbon dioxide emissions by the transportation
section account for a constant share internationally,
and it is necessary to continue to restrict them. On theother hand, it is predicted that in the countries of Asia,
continued economic growth will be accompanied by aswitch to 4-wheel vehicles from motorcycles, which
now have an overwhelming share. This survey willserve as a reminder of the fact that the motorcycle is aroad transport mode superior in its ability to lower
global environmental loads and result in proposals forinternational policies. This survey is now in progressas bilateral joint research with the RDCRB, Indonesia.

300

4‐wheel vehicle with air‐conditioning ON (max. load)

250

4‐wheel vehicle with air‐conditioning OFF
Motorcycle 250cc

200Motorcycle 125cc

150
Motorcycle 50cc

100Electric scooter (equivalent to50cc)

50(N=15～18)

01015
2025
Average traveling speed (km/h)

Figure 1. Relationship of Traveling Speed to Carbon
Dioxide Emissions
Table 1. Average Traveling Speed and Carbon Dioxide
Emissions by Vehicle Type
Items surveyed
Vehicles surveyed
4-wheel vehicle
4-wheel vehicle
Motorcycle
Motorcycle
MotorcycleElectric scooter

Photo 1 View of the Performance of the Survey

30

air-conditioning
ON (max. load)
air-conditioning
OFF
250cc
125cc
50cc
equivalent to 50cc

Averagetraveling speed(km/h)

Average
CO2 Emissions(gCO2/km)

14.7

287.2

15.3

184.0

17.9
18.4
15.5
15.5

62.7
66.3
50.4
11.0

Acknowledgments : Authors are grateful to Yamaha Motor
Co. Ltd. for temporarily providing the electric scooters.