April 5, 2019

Analysis of Roadway Safety Under Alternative Project Delivery Systems


In the United States, most highway projects have been with using the traditional design-bid-build delivery system. Moving on to regular
conditions assessment, maintenance of a road is then performed on the basis of the availability of funds and the priorities established for
road maintenance. When maintenance funds are scarce, serviceability of roads is impacted, which affects road safety. The alternative
project delivery systems, such as design-build-operate-maintain, design-build-finance-operate-maintain, and other public-private
partnership (PPP) models, provide for more consideration of the life cycle of highways. Particularly under performance-based long-term
contracts, which are the norm for PPP systems, road maintenance and performance become controlling parameters in compensating
contractors for their work. With serviceable, well maintained roads, it is expected that road safety records will improve.
Through content analysis of PPP procurement documents and agreements, this research investigated PPP projects for their contractual
safety terms, such as the design of safety payments, measurements, and safety specifications. Through statistical analysis, the research
surveyed PPP projects’ roadway safety records and compared them with the safety records of states, localities/cities, and public non-PPP
highways. The findings showed that safety rates for PPPs are better than those of traditionally delivered highways, but not on all
dimensions. This was represented by better (lower) injury and accident/crash rates on PPP projects than those rates for state, locality,
and public non-PPP projects. However, the fatality rates on PPP projects experienced instability or fluctuation, as they did not remain
lower in all years and/or on all projects in comparison to public non-PPP projects (PPP fatality rates were better in comparison those of
states and localities). Additionally, this study found that PPP projects did not provide more consideration for safety beyond that normally
available from traditional delivery. Safety was an objective in most (76 percent) of the projects; however, without proactive mechanisms
to implement that objective. Around half of the projects mentioned safety as part of the proposal evaluation, but only two projects
assigned points or weights in the evaluation. None of the projects provided ways tolink the contractors’ compensation to achievement of
better accident/fatality/injury rates of the projects.

Prof. Ahmed Abdel Aziz, Prof. Giovanni C Migliaccio
Luming Shang (Research Assistant)