All roads lead to sustainability: Opportunities to reduce the life-cycle cost and global warming impact of U.S. roadways

Abstract

The preservation and renewal of our transport system come at a significant cost to governmental agencies and contribute significantly towards global greenhouse gas emissions. Across fourteen “average” contexts classified by the U.S. Department of Transportation, this study probabilistically evaluates the life-cycle cost and global warming impact of alternative abatement strategies available to transportation agencies in managing their pavement infrastructure. The research relies on two algorithmic approaches to optimize the management of pavements: a trigger-value technique and a reinforcement learning algorithm. Invariant to traffic volume, our results show that by simply spending more “up front”, transportation agencies not only reduce the global warming impact of their pavements but also save money over their life-cycle. Surprisingly, these savings are particularly noteworthy for lower traffic volume roads typically managed by local municipalities with limited budgets. A higher “up front” investment reduces the global warming impact and life-cycle cost for a typical urban interstate by 19% and 2%, respectively; those life-cycle cost savings grow to nearly 16% for a local urban road while its global warming impact is also mitigated by 16%. We also show that more frequent rehabilitation of lower traffic-volume pavements not only increases agency expenditures but also their global warming impact. Conversely, the global warming impact of larger traffic-volume roadways, which are typically managed by state transportation agencies, can be reduced through increased rehabilitation spending. Our findings provide practitioners with valuable information around the life-cycle cost and savings of available pavement management strategies.