Factors influencing greenhouse gas emissions from road transport and energy consumption in the Extended Bangkok Metropolitan Region, Thailand

doi:10.1016/j.regsus.2025.100231

Abstract

Abstract:

Road transport plays a crucial role in facilitating mobility and the movement of goods, particularly in the Extended Bangkok Metropolitan Region (EBMR), Thailand. This area is undergoing rapid industrialization and urbanization, resulting in significant energy consumption and greenhouse gas (GHG) emissions. This study examined the relationships among individual socioeconomic factors, travel characteristics, and energy consumption characteristics and their impacts on GHG emissions from road transport. The path analysis technique was applied to identify the key driving factors and their causal relationships. The data were collected through 1600 questionnaire surveys with road drivers in representative areas of the EBMR from December 2022 to May 2023. The results revealed that individual socioeconomic factors significantly influenced GHG emissions from road transport. Among the drivers, factors such as income, age, education, and driving experience indirectly influenced travel characteristics and energy consumption characteristics, impacting GHG emissions. Similarly, individual socioeconomic factors affected the travel characteristics of tourists and personal travelers. Driving experience was a crucial factor for public road transport and freight vehicle drivers, influencing travel characteristics and contributing to GHG emissions. These findings highlight the importance of key policy recommendations, such as promoting the adoption of electric vehicles, optimizing public transport, incentivizing low-emission tourism, and modernizing freight transport with clean technologies, to enhance efficiency, reduce emissions, and support regional sustainability. This study provides policy-makers with insights into the key factors influencing GHG emissions across different driving factors, revealing how individual socioeconomic factors impact travel characteristics and energy consumption characteristics. The findings will inform the development of targeted emission reduction strategies and sustainable transport policies.

Key words: Road transport, Energy consumption, Greenhouse gas (GHG) emissions, Travel characteristics, Path analysis, Extended Bangkok, Metropolitan Region (EBMR)

Sutinee CHOOMANEE, Vilas NITIVATTANANON, Kampanart SILVA, Kunnawee KANITPONG, Jai Govind SINGH. Factors influencing greenhouse gas emissions from road transport and energy consumption in the Extended Bangkok Metropolitan Region, Thailand[J]. Regional Sustainability, 2025, 6(3): 100231.

Figures/Tables 8

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Table 1

Factors influencing greenhouse gas (GHG) emissions from road transport and energy consumption."

Group	Conceptual factor		Definition			Unit of conceptual factor		Measurement scale		Abbreviation
Individual socioeconomic factors	Age		The age of individual respondents was categorized into the following groups: 18-25, 26-35, 36-45, 46-55, and >55 years.			years		18-25 years=1; 26-35 years=2; 36-45 years=3; 46-55 years=4; and >55 years=5		Age
	Education level		The highest level of formal education attained by individuals, categorized into levels of below high school, high school, associated degree, bachelor’s degree, and master’s degree or higher.			-		Below high school=1; high school=2; associated degree=3; bachelor’s degree=4; and master’s degree or higher=5		EDU
	Income		The average monthly income of individuals, categorized into ranges of below 460, 461-615, 616-765, 766-920, and >920 USD/month.			USD/month		Below 460 USD/month=1; 461-615 USD/month=2; 616-765 USD/month=3; 766-920 USD/month=4; and >920 USD/month=5		INC
	Family size		The number of individuals residing in the respondent’s household, categorized into ranges of 1-2, 3-4, 5-6, 7-8, and >8 persons/household.			persons/household		1-2 persons/household=1; 3-4 persons/household=2; 5-6 persons/household=3; 7-8 persons/household=4; and >8 persons/household=5		FS
	Vehicle ownership		The number of vehicles owned by an individual, categorized into six groups: no vehicle, 1, 2-3, 4-5, 6-7, and >7 vehicles/person.			vehicles/person		No vehicle=0; 1 vehicle/person=1; 2-3 vehicles/person=2; 4-5 vehicles/person=3; 6-7 vehicles/person=4; and >7 vehicles/person=5		VO
	Driving experience		The number of years an individual has been driving, categorized into below 1, 1-3, 4-6, 7-9, and >9 a.			a		Below 1 a=1; 1-3 a=2; 4-6 a=3; 7-9 a=4; and >9 a=5		DE
Travel characteristics	Trip frequency		The number of trips per week that an individual makes, categorized into 1-10, 11-20, 21-30, 31-40, and >40 trips/week.			trips/week		1-10 trips/week=1; 11-20 trips/week=2; 21-30 trips/week=3; 31-40 trips/week=4; and >40 trips/week=5		TF
	Travel distance		The average distance traveled per trip by an individual, categorized into below 50, 50-100, 101-150, 151-200, and >200 km/trip.			km/trip		Below 50 km/trip=1; 50-100 km/trip=2; 101-150 km/trip=3; 151-200 km/trip= 4; and >200 km/trip=5		TD
	Travel time		The average duration of a trip, categorized into below 1, 1-2, 3-4, 5-6, and >6 h/trip.			h/trip		Below 1 h/trip=1; 1-2 h/trip=2; 3-4 h/trip=3; 5-6 h/trip=4; and >6 h/trip=5		TT
	Road type		The category of road type preference that used by the individual as local highway, rural road, main highway, concession highway and motorway.			-		Local highway=1; rural road=2; main highway=3; concession highway=4; and motorway=5		RT
	Speed		The average speed at which a vehicle is driven, categorized into below 40, 40-60, 60-80, 80-100, and >100 km/h.			km/h		Below 40 km/h=1; 40-60 km/h=2; 60-80 km/h=3; 80-100 km/h=4; and >100 km/h=5		SP
	Number of passengers		The number of passengers in the vehicle per trip, categorized into 1-5, 6-10, 11-15, 16-20, and >20 persons/trip.			persons/trip		1-5 persons/trip=1; 6-10 persons/trip=2; 11-15 persons/trip=3; 16-20 persons/trip=4; and >20 persons/trip=5		NP
Energy consumption characteristics	Fuel type		The type of fuel or energy used by a vehicle, such as diesel, gasoline, liquefied petroleum gas (LPG), compressed natural gas (CNG), or electricity.			-		Diesel=1; gasohol=2; LPG=3; NGV=4; and electric=5		FT
Energy consumption characteristics		Refueling frequency			The number of times a vehicle is refueled per week, categorized as 1-2, 3-4, 5-6, 7-8, and >8 times/week.	times/week		1-2 times/week=1; 3-4 times/week=2; 5-6 times/week=3; 7-8 times/week=4; and >8 times/week=5		FR
		Amount of fuel/energy refueling		The average amount of fuel/energy refueled per refill, categorized by quantity, as less than 40, 40-60, 60-80, 80-100, and >100 L.			L, kg, or kW•h (depending on the fuel/energy type)		Less than 40 L=1; 40-60 L=2; 60-80 L=3; 80-100 L=4; and >100 L=5		AE
		Fuel economy		The average distance a vehicle can travel per liter of fuel or per kilowatt-hour of energy, categorized as below 8, 8-10, 11-13, 14-16, and >16 km/L.			km/L or kW•h		Below 8 km/L=1; 8-10 km/L=2; 11-13 km/L=3; 14-16 km/L=4; and >16 km/L=5		FE
		Engine size		The engine capacity of the vehicle, categorized as below 1000, 1000-1400, 1401-1800, 1801-2200, and >2200 cm³.			cm³		Below 1000 cm³=1; 1000-1400 cm³=2; 1401-1800 cm³=3; 1801-2200 cm³=4; and >2200 cm³=5		ES
		Vehicle loading		The total weight of the vehicle when fully loaded, including cargo or passengers, categorized as below 1000, 1001−1300, 1301−1500, 1501−1800, and >1800 kg.			kg		Below 1000 kg=1; 1001-1300 kg=2; 1301-1500 kg=3; 1501-1800 kg=4; and >1800 kg=5		VL

Table 1

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