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The impact of public-private partnerships for roadway projects on traffic safety: An exploratory empirical analysis of crash frequencies

Sonduru Pantangi, Sarvani; Fountas, Grigorios; Tawfiq Sarwar, Md; Bhargava, Abhishek; Mohan, Satish B.; Savolainen, Peter; Ch. Anastasopoulos, Panagiotis

Authors

Sarvani Sonduru Pantangi

Md Tawfiq Sarwar

Abhishek Bhargava

Satish B. Mohan

Peter Savolainen

Panagiotis Ch. Anastasopoulos



Abstract

Since the mid-2000s, Public-Private Partnerships (PPP) have been established in transportation infrastructure projects as an effective alternative to the traditional procurement process, such as design-bid-build where the design and construction are awarded separately and sequentially to private firms. PPP contracts ensure both greater participation of the private sector, as well as shared responsibility in project delivery. However, the interrelationship between various PPP approaches and the status of traffic safety during the project implementation has not been thoroughly explored to date. This paper seeks to provide new insights into the performance of different PPP contracting approaches by investigating them from the perspective of transportation safety. To that end, a statistical analysis is conducted in order to distinguish differences with respect to the characteristics of crashes that occurred during the contractual period of roadway projects. Using data from 645 PPP contracts that were executed across multiple States of the US between 1996 and 2011, count data models of crash frequencies are developed. To take into account the effect of unobserved factors on crash frequencies, correlated random parameter models with heterogeneity in the means are estimated. The results of the statistical analysis overall show that the determinants of crash frequencies and the magnitude of their impacts vary across PPP types. Contracts with higher cost, shorter duration, fewer lane-miles to be covered, more asset work activities, as well as contracts for roadways featuring better pavement and drainage conditions, low to medium AADT, and higher width of shoulder are more likely to observe fewer crashes. Additionally, several variables resulted in correlated random parameters (such as, contract size in lane-miles and truck percentage), with their distributional characteristics being affected by other exogenous factors (such as pavement characteristics), thus unveiling the heterogeneous patterns underpinning the safety performance of different PPP approaches.

Citation

Sonduru Pantangi, S., Fountas, G., Tawfiq Sarwar, M., Bhargava, A., Mohan, S. B., Savolainen, P., & Ch. Anastasopoulos, P. (2022). The impact of public-private partnerships for roadway projects on traffic safety: An exploratory empirical analysis of crash frequencies. Analytic Methods in Accident Research, 33, Article 100192. https://doi.org/10.1016/j.amar.2021.100192

Journal Article Type Article
Acceptance Date Oct 30, 2021
Online Publication Date Nov 8, 2021
Publication Date 2022-03
Deposit Date Nov 11, 2021
Publicly Available Date May 9, 2023
Journal Analytic Methods in Accident Research
Print ISSN 2213-6657
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 33
Article Number 100192
DOI https://doi.org/10.1016/j.amar.2021.100192
Keywords Public-Private Partnerships; Crash Frequency; Negative Binomial; Poisson; Correlated Random Parameters; Unobserved Heterogeneity
Public URL http://researchrepository.napier.ac.uk/Output/2820655

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