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Alternate Route Handbook

Alternate Route Handbook cover

Publication No. FHWA-HOP-06-092
EDL No. 14261
May 2006

Table of Contents

  1. Introduction
  2. Background
  3. Alternate Route Planning Process
  4. Alternate Route Selection
  5. Alternate Route Plan Development
  6. Traffic Management Planning
  7. Implementation

List of Figures

Figure 1-1. Example of traffic diversion
Figure 2-1. Example of an incident requiring the use of an alternate route
Figure 2-2. Buckling of I-95 due to tanker fire
Figure 2-3. Damaged freeway-to-freeway ramp after Northridge earthquake
Figure 2-4. Damaged freeway mainline section after earthquake
Figure 2-5. Alternate routes after Northridge earthquake
Figure 2-6. Commercial vehicle restriction sign
Figure 2-7. Truck detour route trailblazer
Figure 2-8. Stakeholders involved in selecting candidate alternate routes
Figure 2-9. Stakeholders involved in alternate route plan development
Figure 2-10. Barriers to developing alternate route plans
Figure 2-11. Criteria for selecting candidate alternate routes
Figure 2-12. Resources used to inform motorists to divert to an alternate route
Figure 2-13. Methods of accommodating diverted traffic along an alternate route
Figure 2-14. Methods of guiding drivers along an alternate route
Figure 3-1. Stakeholder meeting
Figure 3-2. Alternate route planning process
Figure 4-1. Using a demand model in alternate route selection
Figure 4-2. GIS map for alternate route planning in Oklahoma
Figure 4-3. Alternate route analysis and recommendations
Figure 4-4. Alternate route plan showing a primary and secondary alternate route
Figure 5-1. Sample alternate route plan
Figure 5-2. Specification of traffic signal jurisdiction on an alternate route plan
Figure 5-3. Alternate route plan showing law enforcement traffic control locations
Figure 5-4. Alternate route plan showing interchange and intersection details
Figure 5-5. Legend showing ownership and roadway pavement type
Figure 5-6. Graphic of trailblazers included in an alternate route plan
Figure 5-7. Detailed alternate route plan in urban area
Figure 5-8. Detailed alternate route plan in rural area
Figure 5-9. Alternate route plan showing freeway and street alternate routes
Figure 5-10. Implementation flowchart
Figure 5-11. Alternate route activation checklist
Figure 5-12. Contact matrix for a regional freeway alternate route plan
Figure 5-13. ITS equipment location map
Figure 5-14. Alternate route traffic signal timing plan
Figure 5-15. CMS message plan
Figure 5-16. HAR message plan
Figure 5-17. Response plan for incident of intermediate duration
Figure 5-18. Response plan for incident of extended duration
Figure 6-1. Color-coded alternate route trailblazer sign
Figure 6-2. Mandatory and voluntary alternate route signage
Figure 6-3. CMS informing drivers of a freeway closure
Figure 6-4. Law enforcement diverting traffic
Figure 6-5. Trailblazers with changeable arrow
Figure 6-6. Fold-out sign
Figure 6-7. Trailblazer signage at signalized intersection along alternate route
Figure 6-8. Color-coded alternate route trailblazer signs
Figure 6-9. Incident management traffic control signs
Figure 6-10. Standard signing plan for flagger-controlled intersection
Figure 6-11. Alternate route narrative
Figure 7-1. Changeable message sign message diverting traffic to an alternate route

List of Tables:

Table 1-1. Congestion impacts of planned and unplanned events
Table 2-1. Criteria for implementing alternate route plans
Table 2-2. Criteria for terminating alternate route plans
Table 3-1. Checklist of minimum and ideal actions under alternate route selection planning phase
Table 3-2. Checklist of minimum and ideal actions under alternate route plan development phase
Table 3-3. Checklist of minimum and ideal actions under traffic management planning phase
Table 3-4. Stakeholder involvement in each phase of the alternate route planning and implementation process
Table 3-5. Overcoming barriers to developing alternate route plans
Table 4-1. Stakeholder involvement in establishing alternate route criteria
Table 4-2. Criteria for alternate route selection
Table 4-3. Stakeholder involvement in assembling and indexing data
Table 4-4. Stakeholder involvement in identifying preliminary alternate routes
Table 4-5. Stakeholder involvement in conducting alternate route site visit
Table 4-6. Stakeholder involvement in evaluating preliminary alternate routes
Table 5-1. Stakeholder involvement in determining alternate route plan content
Table 5-2. Stakeholder involvement in developing alternate route plan implementation guidelines
Table 5-3. Stakeholder involvement for developing guidelines for discontinuing alternate route plan
Table 6-1. Methods of information dissemination
Table 6-2. Stakeholder involvement for determining information dissemination methods for notifying motorists of an alternate route
Table 6-3. Stakeholder involvement in determining information dissemination methods to guide motorists along alternate route
Table 6-4. Stakeholder involvement in determining traffic control measures to implement on alternate route
Table 7-1. Stakeholder involvement in alternate route plan implementation
Table 7-2. Implementation plan checklist


This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. This report does not constitute a standard, specification, or regulation.

The United States Government does not endorse products or manufacturers. Trade and manufacturers' names appear in this report only because they are considered essential to the object of the document.

Technical Report Documentation Page

1. Report No.
2. Government Accession No. 3. Recipient's Catalog No.
4. Title and Subtitle
Alternate Route Handbook
5. Report Date
May 2006
6. Performing Organization Code
7. Author(s)
Dunn Engineering Associates, P.E., Consulting Services
8. Performing Organization Report No.
9. Performing Organization Name and Address
Science Applications International Corp., 1710 SAIC Drive, McLean, VA 22102

Dunn Engineering Associates, P.E., 66 Main Street, West Hampton Beach, NY 11978

Woodward Communications, 1420 N St. NW, ste. 102, Washington, DC 20005
10. Work Unit No. (TRAIS)
11. Contract or Grant No.
12. Sponsoring Agency Name and Address
Federal Highway Administration
400 Seventh Street, SW, HOTO-1
Washington, DC 20590
13. Type of Report and Period Covered
Final Report
14. Sponsoring Agency Code
15. Supplementary Notes
This document is prepared under contract by SAIC with assistance from Dunn Engineering Associates for authoring and Woodward Communications for editing and layout.
16. Abstract
This report describes and defines what alternate route traffic routes are and how traffic and highway agencies can implement them. The need for, planning, and execution of alternate routes with stakeholder agencies is addressed. Highway and traffic agencies, public safety agencies, and State, county and local municipalities are the target audience.
17. Key Word
Alternate Routes, Emergency Routing, Traffic Incidents, Traffic Incident Management, Planned Special Events, Event Management, Road Weather, Emergencies, Emergency Management, Emergency Traffic Management, Traffic Control
18. Distribution Statement
This document may be distributed without restriction.
19. Security Classif. (of this report)
20. Security Classif. (of this page)
21. No. of Pages
22. Price

Form DOT F 1700.7 (8-72)   Reproduction of completed page authorized

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