Assessing Indirect Effects and Cumulative Impacts under NEPA
Home » Resources & Research » Practitioner’s Handbooks » Assessing Indirect Effects and Cumulative Impacts under NEPA

Assessing Indirect Effects and Cumulative Impacts under NEPA
This handbook is intended to assist practitioners in assessing indirect effects and cumulative impacts in the evaluation of transportation projects under the National Environmental Policy Act (NEPA). Issues covered in this handbook include: Understanding the definitions of direct effects, indirect effects, and cumulative impacts; gathering the information needed for the analysis; deciding the appropriate scope and level of detail; carrying out the analysis; identifying mitigation opportunities; documenting the analysis; and using the transportation planning process to support NEPA-level studies of indirect effects and cumulative impacts.
Handbook Resources
CEQ Guidance
CEQ, “Forty Most Asked Questions Concerning CEQ’s National Environmental Policy Act Regulations” (March 16, 1981)
http://ceq.hss.doe.gov/nepa/regs/40/40p3.htm
CEQ, “Considering Cumulative Effects under the National Environmental Policy Act” (1997)
http://ceq.hss.doe.gov/nepa/ccenepa/ccenepa.htm
FHWA Guidance
FHWA, “Questions and Answers Regarding the Consideration of Indirect and Cumulative Impacts in the NEPA Process” (2003)
http://www.environment.fhwa.dot.gov/strmlng/newsletters/may03nl.asp
NCHRP Reports
NCHRP Report 403, “Guidance for Estimating the Indirect Effects of Proposed Transportation Projects” (1998)
http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=742
NCHRP Report 466, “Desk Reference for Estimating the Indirect Effects of Proposed Transportation Projects” (2002)
http://apps.trb.org/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=741
NCHRP 25-25 Task 43, “Legal Sufficiency Criteria for Adequate Indirect Effects and Cumulative Impacts Analysis as Related to NEPA Documents” (2008)
http://144.171.11.40/cmsfeed/TRBNetProjectDisplay.asp?ProjectID=761
State DOT Guidance Documents
California DOT, “Guidance for Preparers of Cumulative Impact Analysis” (2005)
http://www.dot.ca.gov/ser/cumulative_guidance/approach.htm
California DOT, “Guidance for Preparers of Growth-related, Indirect Impact Analyses” (2006)
http://www.dot.ca.gov/ser/Growth-related_IndirectImpactAnalysis/gri_gu
idance.htm
Florida DOT, “Cumulative Effects Evaluation – Quick Guide” (Dec. 2012)
http://www.dot.state.fl.us/emo/pubs/CEE/CEE-QuickGuide-2012-1218.pdf
Maryland State Highway Administration, “Indirect and Cumulative Effects Analysis Guidelines (2007)
http://www.sha.state.md.us/OPPEN/ICE-Introduction.pdf
Montana DOT, “Assessing the Extent and Determinates of Induced Growth” (2013)
http://www.mdt.mt.gov/research/projects/planning/growth.shtml
Ohio DOT, “Guidance on Indirect Effects and Cumulative Impacts Analyses” (2014)
https://www.dot.state.oh.us/Divisions/Planning/Environment/NEPA_policy
_issues/Documents/ODOT%20ICE%20Guidance%20(FINAL%20version).pdf
Pennsylvania DOT, “Indirect and Cumulative Effects Guidance (2008)
http://www.dot.state.pa.us/public/PubsForms/Publications/PUB%20640.pdf
Texas DOT, “Environmental Handbook Indirect and Cumulative Impacts” (2014)
http://www.txdot.gov/inside-txdot/division/environmental/compliance-to
olkits/impacts.html
Washington State DOT, “Guidance on Preparing Cumulative Impact Analyses” (2008)
http://www.wsdot.wa.gov/Environment/Compliance/techguidance.htm#Cumulative
Wisconsin DOT, “Guidance for Conducting an Indirect Effects Analysis” (2007)
http://www.dot.wisconsin.gov/localgov/land/effects.htm