Institute of Transportation Studies at UC Berkeley

Highway pavement rehabilitation (HPR) is a service provided by departments of transportation (DOTs) worldwide. The process of delivering HPR projects involves not only a transportation department but also many other project participants and stakeholders; furthermore, it is subject to numerous technical- as well as socio-political considerations. Interestingly—though not surprisingly—the processes DOTs use to deliver this service vary widely, not only between countries or between states in the US, but also regionally within a given state such as California. While some variation is to be expected, it is not necessarily of value to some or all concerned. Management practices such as Lean and Six Sigma can be key to driving out unwanted variation and thereby lead to performance improvements locally and overall. Addressing “Goal 5 Operational Excellence” in Caltrans’ (2015a) Strategic Management Plan, this research set out to view HPR projects through the lenses of Lean and Six Sigma, in combination referred to as Lean Six Sigma. These management philosophies—herein broadly referred to by the broad term “Lean Thinking”—overlap in concepts and methods, but they all aim to promote continuous improvement and value delivery. Caltrans started to launch Lean Six Sigma initiatives in 2015 (e.g., Dunning 2016, Tusup 2017) and its employees have to date already achieved significant process improvements in their day-today operations. However, it appears that Caltrans has not yet pursued such initiatives in the delivery of its projects. The literature overview provided in this report describes applications of Lean and Six Sigma in transportation departments in the US and abroad, and the cases referenced demonstrate the applicability of Lean and Six Sigma to project delivery. Lean applied to HPR project delivery and, more generally, applied to project-based production, in the literature gets referred to using the term “Lean Construction” (Koskela et al. 2002, Ballard et al. 2002). The exploratory research with findings presented in this report, set out to investigate if and how a state DOT might standardize the delivery of HPR projects. The researchers investigated this by collecting data on three projects that Caltrans completed recently. Using this data and building on the Caltrans (2016) work breakdown structure, they were able to map the processes used to deliver two of them. The researchers then obtained further data and gauged the performance of these projects’ delivery processes. Comparison of the resulting process maps, and their combination into a single process map that may function as a draft “standard,” serve as the basis for formulating recommendations to Caltrans. The researchers recommend that Caltrans personnel with a Lean mindset review the maps provided and fine-tune them for further use in collaborative efforts within their organization (e.g., engaging multiple functional units within districts and engaging multiple districts) as well as with supply chain partners (e.g., contractors) while using Lean Thinking to identify and pursue opportunities for continuous improvement of its project delivery practices.