ICCE 2022

How to Cite

HIGHWAYS IN THE COASTAL ENVIRONMENT: NEW USA GUIDANCE. (2023). Coastal Engineering Proceedings, 37, management.36. https://doi.org/10.9753/icce.v37.management.36


There are over 60,000 miles (100,000 km) of coastal highways in the United States (US) that are occasionally exposed to coastal waves and water levels. Wise stewardship calls for the integration of coastal engineering principles and practices in the planning and design of these roads and bridges to make them more resilient. A new, 3rd, edition of the primary guidance document Hydraulic Engineering Circular No. 25 (HEC-25), entitled “Highways in the Coastal Environment” was recently released by the Federal Highway Administration (FHWA). It provides guidance on a range of issues for the design, planning and operation of coastal highways. This manual should help those with little experience in coastal engineering to understand and, as appropriate, to apply scientific methods and engineering approaches that are unique to the coast. For experienced coastal engineers, this manual should serve as a reference document in providing specific highway-oriented assistance and consultation for FHWA and state Department of Transportation projects.


Douglass, Chen, Olsen, Edge and Brown (2006) “Wave Forces on Bridge Decks.” report by the Coastal Transportation Engineering Research and Education Center of the University of South Alabama to FHWA. Washington D.C. 74 pp.

FHWA (2020) Highways in the Coastal Environment, Hydraulic Engineering Circular No. 25, FHWA-HIF-19-059. Fox-Kemper, Hewitt, Xiao, Aðalgeirsdóttir, Drijfhout, Edwards,…, and Yu (2021), “Ocean, Cryosphere and Sea Level Change. In Climate Change 2021: The Physical Science Basis. Contribution of Working Group I to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change [Masson-Delmotte, et al.] Cambridge University Press, pp. 1211–1362, doi:10.1017/9781009157896.011.

Kilgore, Thomas, Douglass, Webb, Hayhoe, Stoner, Jacobs, Thompson, Herrmann, Douglas, and Anderson (2019) “Applying Climate Change Information to Hydrologic and Coastal Design of Transportation Infrastructure – Final Report.” NCHRP 15–61, The National Cooperative Highway Research Program, March 22, 2019, 384 pp.

NHI (2022) National Highway Institute Course #135082, Highways in the Coastal Environment, https://www.nhi.fhwa.dot.gov/downloads/catalog/FHWA-NHI-135082.pdf

Webb, Dix, Douglass, Asam, Cherry, and Buhring (2019) “Nature-Based Solutions for Coastal Highway Resilience: An Implementation Guide.” FHWA-HEP-19-042. Washington, D.C. Federal Highway Administration.

Webb, Douglass, and Cleary (2020) “Contribution of relative sea-level rise to bridge failure in the USA during Hurricane Ivan,” Proceedings of the Institution of Civil Engineers – Forensic Engineering, https://doi.org/10.1680/jfoen.20.00010

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Copyright (c) 2023 Scott Douglass, Joseph Krolak, Bret Webb