Study finds CNG conversion policy in Bangladesh did result in more travel; congestion costs still half the health benefits
Several years ago, the government of Bangladesh took took various policies to convert the petroleum vehicles on road to run on compressed natural gas (CNG), which allows both air quality improvements and energy security benefits. In a 21013 study, researchers found large air quality and associated health benefits accruing to the residents of Dhaka (the capital of Bangladesh) as a result of the rapid conversion of the motor vehicle fleet to CNG. (Earlier post.) Now, however, there is a widespread belief among policymakers that the CNG conversion may have increased car ownership and car travel due to their lower running costs, resulting in more congestion; a reversal of the strategy is possible.
In a follow-on to the 2013 study, Zia Wadud at the University of Leeds has published a new paper in the journal Transportation Research Part A: Policy and Practice, which presents the results of a questionnaire survey and an econometric intervention analysis to understand the impact of CNG conversion on car ownership and car travel in Dhaka.
He found that:
CNG cars travel 35% more, 55% of this due to price effect, the rest due to self-selection.
Total vehicle travel increased by 4.4%, congestion costs increased by 9.6%.
Congestion costs are still one-half of the health benefits of the CNG conversion policy.
Zia Wadud (2014) “(Unintended) Transport impacts of an energy-environment policy: The case of CNG conversion of vehicles in Dhaka,” Transportation Research Part A: Policy and Practice, Volume 66, Pages 100-110 doi: 10.1016/j.tra.2014.04.017