Literature Review Memorandum Page i - Michigan · Literature Review Memorandum Page i ......

Literature Review Memorandum Page iMDOT Best Practices in Emergency Rerouting December 2011

TABLEOFCONTENTS

PURPOSEFORLITERATUREREVIEW....................................................................................................................................1AlternateRoutePlanDevelopment.....................................................................................................................................2OutlineforReviewofPrograms............................................................................................................................................3

BESTPRACTICES...............................................................................................................................................................................4Idaho....................................................................................................................................................................................................4

Description:.................................................................................................................................................................................4Purpose:........................................................................................................................................................................................4TypesofSignageUsed:...........................................................................................................................................................4DevelopReroutingPlans:......................................................................................................................................................5PerformanceMeasures:.........................................................................................................................................................5EvaluationMethodsforPerformanceMeasures:......................................................................................................5

Wisconsin..........................................................................................................................................................................................8Description:.................................................................................................................................................................................8Purpose:........................................................................................................................................................................................8TypesofSignageUsed:...........................................................................................................................................................8DevelopReroutingPlans:......................................................................................................................................................8PerformanceMeasures:.........................................................................................................................................................8EvaluationMethodsforPerformanceMeasures:......................................................................................................9

NewJersey.....................................................................................................................................................................................14Description:..............................................................................................................................................................................14Purpose:.....................................................................................................................................................................................14TypesofSignageUsed:........................................................................................................................................................14DevelopReroutingPlans:...................................................................................................................................................15PerformanceMeasures:......................................................................................................................................................15EvaluationMethodsforPerformanceMeasures:...................................................................................................16

Washington...................................................................................................................................................................................17Description:..............................................................................................................................................................................17Purpose:.....................................................................................................................................................................................17TypesofSignageUsed:........................................................................................................................................................17DevelopReroutingPlans:...................................................................................................................................................18PerformanceMeasures:......................................................................................................................................................18EvaluationMethodsforPerformanceMeasures:...................................................................................................18

Colorado.........................................................................................................................................................................................19Description:..............................................................................................................................................................................19Purpose:.....................................................................................................................................................................................20TypesofSignageUsed:........................................................................................................................................................20DevelopReroutingPlans:...................................................................................................................................................21PerformanceMeasures:......................................................................................................................................................21EvaluationMethodsforPerformanceMeasures:...................................................................................................21

Literature Review Memorandum Page iiMDOT Best Practices in Emergency Rerouting December 2011

Arizona............................................................................................................................................................................................22Description:..............................................................................................................................................................................22Purpose:.....................................................................................................................................................................................22TypesofSignageUsed:........................................................................................................................................................22DevelopReroutingPlans....................................................................................................................................................22PerformanceMeasures:......................................................................................................................................................23EvaluationMethodsforPerformanceMeasures:...................................................................................................23

California........................................................................................................................................................................................24Description:..............................................................................................................................................................................24Purpose:.....................................................................................................................................................................................24TypesofSignageUsed:........................................................................................................................................................25DevelopReroutingPlans:...................................................................................................................................................26PerformanceMeasures:......................................................................................................................................................28EvaluationMethodsforPerformanceMeasures:...................................................................................................28

GeneralGuidanceofAlternateRoutePlan...................................................................................................................30REFERENCES................................................................................................................................................................................32

FIGURESFigure 1. Manual Flow of Information.......................................................................................................................................2Figure 2. Example ITD District 2 Alternate Route Involving Neighboring State....................................................6Figure 3. Idaho Trailblazer Signage at Signalized Intersections......................................................................................6Figure 4. Detailed Alternate Route Plan for Urban Area....................................................................................................7Figure 5. Wisconsin Trailblazers..................................................................................................................................................9Figure 6. Example 1 WisDOT Alternate Route...................................................................................................................10Figure 7. Example 2 WisDOT Alternate Route...................................................................................................................11Figure 8. New Jersey DOT Specification of Traffic Signal Jurisdiction on an Alternate Route.....................15Figure 9. ARTI Traffic Management Communication Diagram..................................................................................29

TABLES

Table 1. Alternate Route Planning Process (Appendix A).......................................................................................27

Literature Review Memorandum Page 1MDOT Best Practices in Emergency Rerouting December 2011

PURPOSEFORLITERATUREREVIEWThe purpose of this project is to provide the Michigan Department of Transportation (MDOT) with a bestpractices document and guidance for identifying, defining, signing, and implementing alternative routesthat accommodate traffic during an incident or weather event. The guidance for implementation willinclude the recommendation of signage (permanent or portable) along the highway, selection of alternateroutes, and performance measures that allow MDOT to evaluate the impact of the route. Interagencyagreements are one recommendation for supporting effective alternate route implementations, and thisguidance will include templates and sample language for those agreements as well as the identification ofthe agencies that should be included.

This literature review serves as the first step for this research effort and provides best practices fromthroughout the country on the development, use, and success of alternate route planning andimplementation.

The identification of candidate states to survey is being conducted in parallel with this literature review. Itis anticipated that candidate states identified for the survey will overlap with the states included withinthis literature review; however some states that have implemented robust programs have not madedocumentation of those programs readily available within the public domain. The lack of publiclyavailable documentation made it difficult to integrate those programs within this literature reviewdocument, but the research team anticipates relationships with these states will foster valuable input fromthe survey effort. Assembling the results from both the survey and the literature review will generate asolid list of five states to move forward into more in-depth interviews. The process described above, alongwith other steps in the research effort, is depicted in Figure 1.


Figure 1. Manual Flow of Information

AlternateRoutePlanDevelopmentAs stated in the publication 2010 Best Practices in Traffic Incident Management, several states –including CA (Anaheim), FL (Northeast), ME/NH, NJ/PA (Delaware Valley Region), WI, and others —have active alternate route plans in place. There are several regional areas also have active alternate routeplans.

The following components are typically included in an alternate route plan:

Detailed alternate route maps;

Process for how to implement the alternate route;

Maps of supporting ITS equipment; and

Traveler information plan for directing traffic around the incident/weather closure.


Not all of the plans examined for this literature review included each and every one of the componentslisted above; however, many of the plans do incorporate additional tools that help to influence thedecisions and use of specific alternate routes.

OutlineforReviewofProgramsAreas of interest for this literature review were states and larger regional areas that regularly encounterweather or incidents that result in the need to use alternate plans that manage the traffic flow in responseto the event. These locations generally fell within the Northern Plains states as well as the Midwest,although specific regions of a few states, such as Northern California and Northern Arizona, alsodemonstrated characteristics that are similar to Michigan’s geographic and operational environment. Theformat for alternate route planning can vary from the development of a stand-alone plan to guidelines fortraffic incident management response plans. Each state also has specific protocols for the use of signage(permanent and temporary) freeways and arterials.

The use of alternate plans is not always clearly documented and readily available; therefore, more in-depth interviews following this task will provide further detail regarding specifics within each program.The literature review conducted for this project focused on six general areas.

A description of the program and references to alternate routing within that state

The purpose of the program or plans for alternate routing

Types of signage used (permanent or temporary) and density or location of installations

Methods used to develop alternate routes (based on type of road, freight, jurisdictionalrelationships, and emergency responder/DOT/police relationships)

Identification of performance measures (specifically regarding or referencing how well alternateroutes are working)

Evaluation methods for performance measures that were established for alternate routing

Seven states were included in the literature review; they are listed below. Each of the states that werereviewed has implemented multiple alternate routing plans. Many states or regions that were researchedhave not published their approach or use of plans or the benefits that have resulted from implementation.Despite the challenge presented by this lack of published information, the results of this literature reviewstill provide the foundation that will allow the project to move forward with in-depth interviews.

Idaho Washington California

Wisconsin Colorado

New Jersey Arizona


BESTPRACTICES

Idaho

Description:Idaho State Police—in coordination with the Idaho Transportation Department (ITD), emergencyresponders, local agencies, and public agencies—have agreed on the purpose of the Idaho TransportationIncident Management Plan (January 2008). Per the ITD publications website, the plan was created to“provide an efficient coordinated response to, and management of, any major traffic delay or hazard.” Thetypes of incidents covered include crashes, stalled or stopped vehicles, and obstructions that require laneclosures and traffic control. Idaho is concerned with slow incident response and the recovery of trafficflow following incidents. This plan involves the development of alternate routes for each of the six ITDDistricts in the state. It focuses on primarily using state facilities (highways, interstates, state routes), butalso includes routing traffic onto County and local roads when there is no reasonable alternate using astate facility. An example of an alternate route established for District 2 is shown in Figure 2. Thisexample is additionally unique, in that is involves the use of roadways within Idaho’s neighboring state,Washington.

The Idaho Transportation Incident Management Plan provides a checklist and notification procedures,contact information, training specifications, and overall general information on the procedures to respondto an incident. It classifies incidents using three types of responses: Response A (up to 30 minutes);Response B (30 minutes to 2 hours); or Response C (more than 2 hours).

As part of this effort, a Transportation Incident Management Plan Quick Reference Guide was developedto help incident responders communicate appropriate information in the most efficient way possible. Thisquick reference guide allows the partnering agencies to clear a scene quickly without sacrificing thequality of incident clearance processes. This guide includes notification procedures for establishingalternate routes with the appropriate ITD districts as well as proper placement of detour signs on the mainfacility where the road closure occurred. ITD has discussed the possibility of converting the alternateroutes into a live, active database that can be queried on a moment’s notice as an incident or weatherevent is experienced. This process has not begun.

Purpose:The plan was developed to guide types of incident response coordination and cooperation that couldstreamline the response and clearance process in Idaho. The Quick Reference Guide was developed as asmall notebook for incident responders to have in their glove box as reference for how to clear incidentscenes quickly.

TypesofSignageUsed:As part of this plan, there was no specific signage that was recommended to be deployed to supportalternate routing, although the recommended use of other agency infrastructure (County Highway Districtor local agency) was mentioned where applicable.


In the Alternate Route Handbook developed by FHWA, ITD is highlighted as using trailblazer signage atsignalized intersections along alternate routes (Figure 6-7). This is provided as Figure 3. Figure 4 showsa detailed alternate route plan developed in 2001 for the urban Boise metropolitan area and illustrates howspecific eastbound and westbound devices are planned to be utilized.

DevelopReroutingPlans:The Idaho plan specifies different levels of severity, including the following:

Levels C and D require implementation of a diversion route.

Level C is an incident taking 30-120 minutes from detection to fully restored traffic flow.

Level D is an incident taking over 2 hours from detection to fully restored traffic flow (includingfull freeway closure in one or both directions).

Although the action to “Review alternate route options and/or set up detour (if needed)” is listed last inthe Procedure for Managing the Incident Scene Checklist, there was significant effort involved indeveloping alternate routes, particularly where the alternate had to occur on a County or local roadway.Representatives from agencies responsible for those local routes were present at the stakeholder meetingsto define the alternate route strategy for a particular state facility to ensure there was consensus on the useof that local route. Formal agreements between ITD and the local agencies affected by specific alternateroutes were recommended to confirm and document the ability to potentially use each specific route.

PerformanceMeasures:No performance measures were identified as part of this plan.

EvaluationMethodsforPerformanceMeasures:No evaluation methods were identified.


Figure 2. Example ITD District 2 Alternate Route Involving Neighboring State

Figure 3. Idaho Trailblazer Signage at Signalized Intersections


Figure 4. Detailed Alternate Route Plan for Urban Area


Wisconsin

Description:The Wisconsin Department of Transportation (WisDOT) TIME Program (Traffic Incident ManagementEnhancement) is a multi-agency, multi-discipline program dedicated to coordinating traffic incidentmanagement using both relationships and technology. Developing emergency alternate route guides was apart of the 2006/2007 TIME Action Plan. A memorandum developed in 2008 documents the StatewideEmergency Alternate Route guidelines program.

Purpose:The goal of the Statewide Emergency Alternate Route program is to establish statewide consistency inemergency alternate route guide development and implementation. To accomplish this goal, it wasnecessary to develop a statewide template that guides this standardization effort. The guide and templatewas developed and formatted in a consistent manner such that all emergency alternate route guides in thestate have a similar look and organization.

Per the Emergency Traffic Control and Scene Management Guidelines (dated October 2008), as soon aspossible after arriving at the scene, the activation of an emergency alternate route should be considered. Itdocuments that all impacted agencies should be notified when an emergency alternate route has beenactivated.

TypesofSignageUsed:In many areas of the state, emergency alternate route guides have been developed and/or alternate routesigning has been installed. Portable changeable message signs also can be deployed to assist in notifyingmotorists of and/or guiding motorists along the emergency alternate route. Figure 5 provides a photo oftrailblazers with changeable arrows used in Wisconsin (FHWA Alternate Route Handbook, Figure 6-5).

DevelopReroutingPlans:Alternate routes were recommended to be considered only for incidents that cause delays that will exceed30 minutes. This is the minimum threshold established for a road or multiple lane closure resulting froman incident or weather event. Lengthier events more clearly warrant the use of alternate routes.

The development of these guidelines included local agency coordination with county sheriff’sdepartments, police departments, county highway departments, local fire departments, relevantemergency medical responders, and towing and recovery specialists. Other participants includejurisdictions in neighboring states, emergency management personnel, and municipal public works andlaw enforcement.

Example alternate routes from Wisconsin are provided in Figure 6 and Figure 7.

PerformanceMeasures:To date, emergency alternate routes have been implemented in several corridors in Wisconsin. Thebenefits of using alternate routes have included:


Reducing queue lengths and the potential for secondary crashes

Keeping people and freight moving

Allocating staff and equipment effectively

Improving response time

In the Monthly Performance Measures Report established for WisDOT (dated October 2007, accessedfrom the National Transportation Operations Coalition (NTOC) website), there are a number of measuresreported, including response time, incident clearance times, hours of delay, VMS usage, and othermeasures. There were no measures specifically reported for the use of alternate routes; however, hours ofdelay and incident response and clearance times may influence the effects of the use of alternate routesdepending on the duration of the road/lane closures.

The Statewide Emergency Alternate Route program is creating a mechanism to successfully integratemany of the temporary traffic control concepts contained in Chapter 6I of the Manual on Uniform TrafficControl Devices, as well as WisDOT’s Emergency Traffic Control and Scene Management Guidelines.These concepts include providing traveler information through proper traffic control and adequateincident scene signing. A critical component of a successful ongoing traffic incident managementprogram is regular discussion and continual training for local officials and emergency responders.Guidelines for WisDOT state that emergency alternate routes and use of corresponding guides should beregularly discussed during Regional TIME Committee meetings.


Figure 5. Wisconsin Trailblazers


Figure 6. Example 1 WisDOT Alternate Route


Figure 7. Example 2 WisDOT Alternate Route

General Guidelines from WisDOT:Some key emergency alternate route best practices are provided below.

Actively engaging the appropriate stakeholders is critical to obtaining buy-in and buildingpositive momentum for the project. If it is necessary to utilize facilities not owned by WisDOT,then a memorandum of understanding should be considered.

Permanent signing of the alternate route should be considered so drivers have visual cues toreassure them they are traveling in the correct direction and to guide them back to the freeway.The signing also reduces the need for temporary sign placement and the need for field personnelto guide traffic. Alternate route signing typically consists of a standard interstate shield with theword “alternate” attached above.

Emergency alternate routes should be as short as possible; a 5-mile alternate route is better than adetour of 10 miles or more. Additional signing must be installed on longer routes to reassuremotorists.

When determining whether to implement an emergency alternate route, the following should beconsidered: extent of closure (i.e., number of lanes blocked), duration of closure (greater than 30minutes), potential length of queue, and time of day.


Each emergency incident has its own unique characteristics and circumstances that influence theresponse procedures. Each responding agency has numerous responsibilities; the extent of whichis not known until the scene is assessed. Securing answers to a variety of incident issues oftentakes time, making it challenging to judge the duration of an incident or to make a decision toimplement an alternate route. Education and outreach to the emergency response communityregarding the basic principles of traffic management is essential. This can be effectivelyaccomplished through incident management training sessions.

The emergency alternate route guide should provide practical information than can be readilyused by someone with minimal prior experience with implementing alternate routes. Examples ofthis information include:

– Overview map of the corridor– Detailed map of each freeway segment that indicates location of all interchanges,

roadways, traffic signals, etc.– Locations to place road closure posts, portable changeable message signs (PCMS),

portable static signs, law enforcement for traffic direction, etc.– Recommended messages for PCMS– List of ITS tools available for traffic information, including 511, permanent dynamic

message signs, highway advisory radio, etc.

It is beneficial to have incident management equipment readily available. For example, someagencies have vehicles or trailers that are dedicated to incident response. They are stocked withitems like Type 3 barricades, cones, barrels, and alternate route signing. These trailers areavailable 24 hours per day, seven days per week for incident response.

The emergency alternate route guide will ONLY be modified for major construction projects(e.g., the Marquette Interchange, the North-South Corridor, etc.) that span multiple years andwhen the project has funding or if other projects would significantly impact the emergencyalternate route (i.e., jurisdictional transfers, bridge replacement projects, etc.). For thesesituations, a meeting will be held in conjunction with the WisDOT Regional Traffic IncidentManagement Enhancement (TIME) Committee to discuss potential changes.

Meetings should be held to update the guide, as needed. These meetings provide a valuable forumfor a variety of stakeholders to meet and discuss incident management topics. Meeting face-to-face also helps establish relationships that lead to closer inter-agency cooperation.

Incident debriefing meetings should be held after major incidents to review details of the incident.What worked and why? Were equipment and manpower adequate? Was communicationadequate? Was the guide closely followed? Debrief meetings provide a valuable real-life learningexperience.


In addition to the hardcopy version of the guide, prepare an electronic version of the guide. Theelectronic guide can be distributed on CD ROM and enables dispatchers and users in the field toview the guide from a laptop or mobile data terminal.

Consistency in selecting alternate routes is an important aspect of the program. The followingcriteria provide a common starting point for evaluating potential alternate routes.

– Use state highways whenever possible– Consider long truck routes when available– Avoid alternate routes with weight restrictions– Avoid height restrictions imposed by bridge clearances, power lines, etc.– Avoid routes that require traffic to make 90-degree turns– Avoid at-grade railroad crossings, especially those with a high number of trains– Avoid four-way stops– Select routes that carry traffic in the same general direction as the Interstate– Minimize length of alternate routes– Consider routes with coordinated signal timing plans, or avoid routes with multiple

uncoordinated signals– Avoid traversing residential areas and school zones– Carefully consider all route options and closure requirements at interchanges, especially

system interchanges


NewJersey

Description:As documented in the Traffic Mitigation Guidelines for Work Zone Safety and Mobility developed in2007 by New Jersey DOT (NJDOT), alternate routes are an important consideration when evaluatingtraffic mitigation strategies. Alternate routes can be used when it is important to close the work area toperform certain construction tasks or when diverting traffic will substantially reduce traffic volumes.These strategies are most appropriate if there is available capacity on routes parallel to the road underconstruction and the routes can accommodate the mix of vehicles to be diverted.

It is outlined in the Traffic Mitigation Guidelines that a Draft Traffic Mitigation Plan shall be establishedfor all moderate to high impact projects. The Plan will involve a number of components, including the useof alternate routing, as needed.

The New Jersey 511 system (www.511nj.org) also provides detour routes for major construction projectsas well as a real-time map of state routes in the metropolitan area that can help with setting up detoursduring incident/weather/non-recurrent closures.

Purpose:Appropriate traffic mitigation strategies by project type and project characteristic are provided in theTraffic Mitigation Guidelines. Many of these strategies include the use of alternate routing.

TypesofSignageUsed:Information provided to motorists within and in the vicinity of the construction area can alert motorists todelays caused by construction activity and provide advance notice of changing operating conditions. Thefollowing strategies and tools help to divert traffic to alternate routes during delay periods and improvetraffic flow for motorists who remain in the project area:

Variable Message Signs

Preconstruction signage

Closed Circuit TV (CCTV)

Highway Advisory Radio (HAR)

Advance Information Panel Size

Detour routes might need to be upgraded and/or signal timing adjusted to increase capacity or improvetraffic flow, making them more attractive to motorists.

If traffic will be detoured away from the construction, signage will be needed to inform motorists as towhere the detour route begins, where it rejoins the road under construction, and where they are to make

http://www.511nj.org/


turns along the detour route. Signage also can be useful on non-turn sections of the detour route toreassure motorists they are still on the detour and have not missed any turns.

Ramp metering also can divert motorists to alternate routes, so adequacy of capacity on nearby roadsshould be examined.

Using low frequency broadcast channels, highway advisory radios (HAR) offers motorists an in-vehicleopportunity to obtain detailed information about future projects in the vicinity as well as informationabout alternate routes and other strategies they could consider using during construction.

Figure 8 provides an example specification of traffic signal use on an alternate route.

Figure 8. New Jersey DOT Specification of Traffic Signal Jurisdiction on an Alternate Route

DevelopReroutingPlans:Coordination with local agencies is essential. It also is important to identify alternate routes that aresuitable for truck traffic.

PerformanceMeasures:As with construction strategies, many traffic control strategies can be evaluated by comparison withconditions prior to implementing the strategy and with conditions on similar facilities without thestrategies in place. Reversible lanes, ramp metering, and truck restrictions, for example, can be evaluatedbased on volume of traffic, delay, and accident conditions prior to and after implementation. Other


strategies, such as temporarily reduced speeds, barriers and channelizing devices, and construction areascreening also can be measured through assessment of delay; Speed can be used to assess theeffectiveness of these strategies. Strategies that affect routes off the corridor, such as ramp metering,alternate routes, and temporary parking restrictions, potentially affect not only the construction route butalso parallel routes, in essence relocating traffic congestion. Therefore, similar evaluation measures ofdelay, volume, and speed on these routes should be measured as well.

Typical measures evaluated for these strategies include:

Traffic volumes and peak traffic counts (construction and parallel routes)

Vehicle throughput

Vehicle occupancy counts

Bicycle and pedestrian traffic in construction area

Travel delay and travel time

Crash rates

These measures should be assessed regularly during construction and should be assessed for both peak-and off-peak times. Measurements should be made before, during, and after construction to examineshort- and long- term impacts. For traffic mitigation plans for high impact projects, evaluation also shouldtrack at least some of these measures on non-affected corridors of a similar type of roadway for controlpurposes to rule out the effects of exogenous factors, such as gasoline prices, on the observed results.

Monitoring of delay time on alternate routes might indicate that revised signal timing or additional policeenforcement will be needed to use the alternate routes most effectively.

EvaluationMethodsforPerformanceMeasures:Data collection tools for traffic control and operations are similar to those used to measure the overallcorridor performance. These include standard machine counting or video procedures for traffic counts;direct observation and occupancy questions on surveys to assess vehicle occupancy; and timed runs in a“floating” or “test car” to assess travel time or average travel speed.

For channelizing devices, reduced speed limits, and flashing arrow signs, direct observation of motoristbehavior might be most useful to determine the degree to which travel change is occurring. Videorecording also could be useful to determine to what degree traffic is slowing or diverting as requested.Observation over longer periods of time can be used to reveal patterns of change, such as times of heavytraffic vs. light traffic conditions or daytime vs. nighttime behavior.

The mechanisms for evaluating travel impacts of lane and ramp closures and two-way traffic on dividedhighways are similar to those for tracking general corridor performance, as noted earlier in this section.Standard machine counting or video procedures can be used to conduct traffic counts. Vehicleoccupancies can be measured by direct observation or video, and through surveys, as noted above. VMT


can be assessed through survey questions about trip length. The same cautions about sample size alsoapply here. Delay and speeds can be measured through “floating” or “test car” procedures.

Washington

Description:In July 2002, the Washington State Patrol (WSP), Washington State Department of Transportation(WSDOT), and Washington State Association of Fire Chiefs (WSAFC) proposed a plan to coordinatetheir efforts and resources for responding to, mitigating, investigating, and clearing incidents on highwaysand ferry routes. The three agencies implemented this coordination under the Joint Operations PolicyStatement (JOPS).

The JOPS developed in 2008 documents the joint policy positions between the WSP and WSDOTregarding issues of mutual interest in the operations of Washington State Highways and Washington StateFerries (http://www.watimcoalition.org/pdf/JOPS.pdf). Within the JOPS document, traffic incidentmanagement procedures and responsibilities are outlined as well as winter operations and work zonesafety responsibilities.

In Thurston County, Washington, the Thurston Regional Planning Council facilitated development of acoordinated system for detouring traffic around major blocking incidents on Interstate 5 and US Highway101. The plan, called the Incident Management Handbook for the I-5 Thurston County Corridor, includesroutes in rural and urbanized areas. It involves working with a number of city, county, and state roads aswell as police, communications, and fire departments to establish a coordinated action plan.

Purpose:The objective of the Thurston County plan is to better manage traffic on both the freeway and localarterials when a major incident occurs on the freeway. Detoured traffic is routed onto local streets aroundincidents that block all lanes of the freeway in one direction with an expected duration of more than 2hours. This plan helps manage the inevitable overflow of traffic onto city and county roads with an eyetoward minimizing traveler frustration and improving safety.

According to the Incident Response Program website, Incident Response Teams (IRTs) were created tohelp minimize the impact of congestion. The IRTs are roving assistance patrols located in congested areasduring peak traffic periods. They coordinate with the Washington State Patrol (WSP) and otherresponders to quickly clear roads and help drivers, whether stranded or in a collision. They help to restorethe traffic flow safely and as quickly as possible. IRT personnel are available for emergencies 24 hours aday, 7 days a week. IRT personnel are dispatched by WSP. They assist WSP troopers with short- and/orlong-term traffic control to reduce the likelihood of secondary collisions.

TypesofSignageUsed:No specific signage was reported for use along alternate routes.

http://www.watimcoalition.org/pdf/JOPS.pdf).


DevelopReroutingPlans:As part of the Thurston County plan, a workgroup of staff from all the affected agencies developed mapsof detour routes, a signage plan, a traffic control plan, and a communication plan. WSP, the lead fieldagency, calls for the detour, setting in motion a coordinated response from local and state publicworks/roads, police, emergency communications, and public information officers. It also creates amechanism for cost recovery for local jurisdictions. Future plans include making the plan available real-time, online, in emergency response vehicles through a secured network called Rapid Responder, whichprovides facilities information for first responders. WSP also developed a training video for allparticipating agencies. Developing this plan required multiple agencies to understand and appreciate eachother’s goals and how each agency could contribute to meeting the goals of all—for improving mobility,safety, traveler information, and overall system management.

PerformanceMeasures:The WSDOT estimates for every minute an incident blocks the freeway, up to nine minutes of additionaldelay can occur, often with accidents happening in the backup. No specific performance measures wereidentified for the Thurston County plan or the Incident Response Program.



Colorado

Description:The Colorado Department of Transportation (CDOT) has led the development of a number of trafficincident management plans and programs throughout the state. As of the development of the Guidelinesfor Traffic Incident Management in Work Zones (2008) there were 12 active traffic incident responseprograms for Colorado Interstates and State Highways. The programs areas are listed below.

North I-15 – Weld/Larimer Counties

US-36 – I-25 to Boulder

I-25 – Express Lanes

T-REX Traffic Incident Management Plan – I-25 Broadway to Lincoln Avenue, I-225 Parkway toI-25

South I-25 – Douglas County

DIA – I-225/I-70 Interchange

6th Avenue – Kalamath to I-70

I-70 Mountain Corridor – Morrison to Utah

I-25 El Paso County

Pueblo County

I-25 Trinidad

Park County Highway Incident Management Program

These programs were developed through a multi-agency planning process that involved CDOT, localtransportation agencies, local fire/rescue, law enforcement, emergency medical services, towing services,and other stakeholders in the corridor. The process included reviewing and incorporating existingprotocols and agreements. The programs outline procedures for informing system users and the media,and provide guidance for program implementation and management.

CDOT also publishes Lane Closure Strategy documents on its website for Regions 1-6 specifying theanticipated lane closures throughout the year and the guidelines for application of the strategy tosituations across each of the six regions. These strategies outline the recommended closure that couldsupport traffic during the week without significantly impairing traffic. Although these strategies do notencompass incident/weather/non-recurrent closures, they can be referred to during those events to providea picture of what type of an impact a closure on that facility would have on traffic.


CDOT has COTrip which provides detour information on its website (www.cotrip.org) via the roadcondition map for road works that would create near or full closures. Information is every 10 minutes at aminimum and provides information about how potential alternate routes (if those potential routes are statefacilities) are looking in near real-time.

Purpose:Each of the programs includes an Incident Response Manual that provides a quick, in-the-field referenceto response personnel. This ensures effective, consistent responses to incidents. The manuals contain thefollowing:

Incident levels and associated actions

Lists of response agencies

Roles and responsibilities of response agencies

Contact information and procedures

Scene management guidelines

Predetermined alternate routes

Resource information

According to a CDOT Resident Engineer, “The variable message boards will relay road and travelinformation to motorists in order to help them make informed travel decisions.” The Resident Engineerwent on to state “By giving this information to motorists in advance, we can help reduce congestion anddirect motorists to alternate routes during incidents including inclement weather, construction, andaccidents.”

TypesofSignageUsed:The T-REX Traffic Incident Management Program (2001) provided the following guidelines on how toestablish an alternate route and implement the routes:

After determining that alternate routes should be implemented, the following actions should be taken toestablish an alternate route:

1. CDOT TOC must be notified of any closures or implementation of alternate routes.

2. All agencies affected by the alternate route must be notified. The CDOT TOC will be responsiblefor notifying the appropriate agencies.

3. Upon notification, agencies that have signal systems or detour trailblazers on the alternate routeshould put the appropriate signal timing changes and trailblazers into effect to accommodate thatparticular alternate route. If the agency is not capable of immediately changing the signal timingplans, traffic control personnel should be posted at critical intersections provided along the route.

http://www.cotrip.org/


A map of the signal system jurisdictions and key intersections is provided in the back of the T-REX TIM Response Manual.

DevelopReroutingPlans:One of the actions recommended when impacts to the traveled roadway is considered Intermediate is toconsider implementing alternate routes. Intermediate impacts are defined as lane blockages that areestimated to be greater than 30 minutes, but less than 2 hours and are not a full closure of the roadway.Impacts that are greater than the Intermediate level require implementation of alternate routes andnotification of the impacted jurisdiction (Guidelines for Traffic Incident Management in Work Zones2008). Each of the traffic incident management programs used in Colorado includes predeterminedalternate routes for use during incidents that close the highway.

The T-REX Traffic Incident Management Program (2001) provided the following guidelines on when toestablish an alternate route:

The use of alternate routes should only be considered when there is full closure of the interstate ineither direction or when the Incident Commander deems it necessary for the safety of thetraveling public and responders.

In addition to the above, consideration must be given to the extent of roadway or structuraldamage, and the extent of bodily injury or fatalities.

The final determination to use alternate routes will be made by the Incident Commander based onobservation of the scene.

Remember to contact the CDOT TOC when lanes are reopened to traffic.

PerformanceMeasures:None identified as part of this plan.



Arizona

Description:The Statewide Alternate Route Plan (AZ-485, December 1999), which includes statewide alternate routeplans and Traffic Management Center (TMC) Traffic Incident Management (TIM) operations guidelines,was developed with input from legislative, transportation, law enforcement, fire and rescue, and EMSagencies; the towing industry; and others. The plan includes related traffic control agreements with thetowing industry.

It also provided statewide detour plans for major links of Arizona roadways in print format. That projectresulted in a three-inch-thick binder of closure/detour descriptions. GIS software was used to develop theoriginal detours.

The Arizona Department of Transportation (ADOT) recognized the need for a statewide set of currentalternate routes to supplement the existing detours developed by ADOT District offices.

The Alternate Routing Information System (ARIS) (AZ-513, June 2002) project provided ADOT with anew software tool in a uniform format for determining the best detour options when a roadway closure orrestriction occurs. ARIS, is supported by a map interface, supplemental roadway network data, an ad hoccapability of generating new closure and detour combinations, and presentation of the library of projectSPR-485 approved detour plans.

Purpose:ARIS is intended for Phoenix TOC operators who have difficulty interpreting the wide variety of districtdetour plan formats while coordinating statewide incident management activities for ADOT’s districts.These operators provide coverage statewide during the evening and on weekends.

The 1999 resource that included statewide detour plans was clearly limited in its functionality as well asby its bulk. The ARIS project was then developed to streamline the information in the 1999 plan.

TypesofSignageUsed:VMS locations were planned to be used as a method of communicating incidents/closures and reroutingstrategies.

DevelopReroutingPlans:

The 1999 Alternate Route Plan chose the alternate routes based on criteria including:

A determination of truck restrictions for roads off of the interstate – size, weight, height

A determination of average speeds along the alternate routes to gauge effectiveness as a route

A collection of the following information: bridge points, regulation speed segments, functionalclassification segments, height and width restrictions, VMS locations, and automated access tothe Highway Closures and Restrictions





California

Description:Individual alternate routes have been developed in the Alternate Routes for Traffic Incident (ARTI) Guide(January 2009) in response to specific incident locations on the freeway system. Each alternate routeconsists of the designated route as well as elements used to support its implementation. Many of the fullbuild-out elements do not currently exist along the alternate routes, but they will become part of theoverall system deployment at some time in the future. There are several planned and programmed ITSprojects along these alternate routes that will install some of these future elements.

In conjunction with the implementation of regional alternate routes (i.e., freeway to freeway) by theCalifornia Department of Transportation (Caltrans) during major traffic incidents, the strategy ofdiverting traffic to predetermined local alternate routes around the incident location would facilitatetraffic movement and increase mobility and travel time reliability.

Alternate routes have been developed for the following freeway segments in San Mateo County:

US 101 – From San Francisco County line to Santa Clara County line

I-280 – From San Francisco County line to State Route 92 (SR 92)

I-380 – From US 101 to I-280

SR-92 – From San Mateo Bridge to I-280

The local agency Police Dispatch coordinates with its police officers and public works staff to respond toand manage the diverted traffic on local streets.

Although Caltrans as a statewide agency does not have any formal alternate routing plans developed forstate facilities, Caltrans does periodically initiate traveler information websites during specific projectsthat require longer-term closures that share alternate routes. One such project is along Highway 50, wherethere was a temporary closure in March 2011. Caltrans launched www.Way2Tahoe.com to help travelersduring the planned closure.

Purpose:The primary purpose of the ARTI Guide is to address the effects of non-recurring traffic congestioncaused by major freeway incidents within San Mateo County. The focus of the document includes:

1) Identifying, in advance, emergency alternate routes for use along selective freeway segments;

2) Establishing traffic management response guidelines; and

3) Facilitating inter-agency traffic management communication and coordination processes.

The objective is to provide an approach to partnering with emergency responders to manage trafficdiverted around the incident location and to optimize traffic flow.

http://www.Way2Tahoe.com/


The Guide consists of alternate routes (pre-selected alternate route path diagrams) as well as agencyresponse plans (communications and actions matrix).

TypesofSignageUsed:Alternate route elements identified in the plan include:

Ramp meters – These ramp meters adjust on-ramp flow rates upstream and downstream of theincident in response to freeway traffic. During an incident, flow rate for on-ramps upstream of thefreeway incident would become more restrictive as congestion grows, while flow rate for on-ramps downstream of the incident would become less restrictive (or turned off), helping divertedtraffic clear local streets more quickly. On-ramp metering based on local sensors is in the processof being implemented by Caltrans. Future features may include coordination with other trafficsignals and central systems.

Freeway Changeable Message Signs (CMS) – CMS provide incident and route guidanceinformation to freeway traffic upstream of the incident. These are controlled by Caltrans and arean integral part of disseminating traffic and incident information to drivers on the freeway. A mapshowing relevant CMS for the County is included in Section II (Agency Coordination andResources) for reference only. Message content is often determined “on-the-fly” by Caltransoperators based on current needs. The signs also have the ability to store specific messages forrecurring events.

Traffic signals and flush traffic signal timing plans – Traffic signals assign right-of-way fortraffic along local streets. Flush plans are an operational solution to provide increased throughputcapacity for local streets by adjusting the signal timing to provide extended green times along theparallel arterial street and the local street connectors to and from the freeway to move greateramounts of traffic. There are no flush plans currently developed or in use along the alternateroutes. Future flush plans would need to include provisions for traffic flow between agencies andinter-agency traffic signal timing coordination. Upgrading traffic signal controllers (such as at thelocations listed in Appendix A) can provide additional communication and coordinationcapabilities for implementing flush plans between jurisdictions.

CCTV cameras – Fixed and pan-tilt-zoom (PTZ) CCTV cameras are used to monitor traffic flowand conditions at key locations along the alternate route to monitor the diversion flow and theeffectiveness of traffic management efforts. Fixed cameras typically are installed at intersections(covering the major approaches), while the placement of PTZ cameras is more flexible. VideoDetection Systems (such as at the locations listed in Appendix A of the plan) also use fixedcameras, and there may be an opportunity to extract video from these cameras without having toinstall a new, separate camera.

Electronic trailblazer signs – These signs would provide route guidance for the divertedfreeway traffic along the alternate route as well as direct local street traffic away from enteringthe impacted freeway section. Installation of these devices may be used to replace the personneldeployment locations. Since alternate routes usually go through multiple jurisdictions, the future


operations of these signs would need to include provisions for inter-agency traffic activation andcoordination.

Through installation of ITS equipment along the alternate routes, the stakeholders will have tools andstrategies that will enable them to do the following:

Change route guidance signs to guide incident traffic along a specific alternate route to avoid asituation where drivers seek unknown routes;

Increase the green time along an alternate route during an incident to reduce the travel time.

Monitor traffic on local streets;

Share data and video between agencies to create a regional partnership to manage traffic; and

Coordinate operations between Caltrans and local agencies during major incidents.

Per the System Engineering Management Plan developed for the San Mateo County Smart CorridorsProgram in 2009 (accessed from the FHWA website), Caltrans is required to commit to active operationand control of the Smart Corridor tools by the Caltrans District 4 TMC operators with support from localagencies. Active operation during major freeway incidents includes implementing alternate route signageand monitoring CCTV camera images to optimize the flow of traffic along alternate routes. If necessary,active operation also requires adjusting alternate route device parameters in response to changingconditions. In addition, the system requires communication and coordination between agencies,adjustment of signal timing, notifications to travelers, and implementation of other operational strategiesalong the affected portion of the corridor during a major freeway incident.

DevelopReroutingPlans:Facilitated by the City/County Association of Governments (C/CAG) of San Mateo County and the SanMateo County Transportation Authority (TA), the ARTI Guide was developed through a cooperativeeffort between stakeholders, including the California Highway Patrol (CHP), Caltrans, local city publicworks departments, local police departments, local fire departments, the San Mateo County Office ofEmergency Services (OES), and the Metropolitan Transportation Commission (MTC). Figure 9 providesthe Traffic Management Communication Diagram from the ARTI Guide for the partnerships andcommunications that occur when managing diverted traffic from a freeway incident onto local streets.

Existing Joint Operational Policy Statements between Caltrans and the CHP currently address the sharedresponsibilities for operations and management of the state highway system. Policy Statements that areapplicable to the ARTI Guide include: Incident Management, Traffic Management and Control on StateHighways, and Unplanned Highway Closures and Restrictions. It is intended that the Incident CommandSystem (ICS) and the Standard Emergency Management System (SEMS) processes be implementedduring major freeway traffic incidents. The ARTI Guide would be utilized as a resource to assistemergency responders in managing traffic that is diverted around the incident location and optimizingtraffic flow.


Using the established alternate route selection criteria, City and the County public works departments andthe Traffic Incident Management Committee (TIMC) identified potential arterial streets that weredetermined to be the best candidates as alternate routes for mobilizing a higher demand of traffic duringmajor incidents and seek to contain and/or minimize the impacts of the diverted traffic onto the localstreet network. The alternate routes were developed with considerations for access, previous experience,and local knowledge. The alternate routes were separated into two types: regional and local. Regionalroutes are primarily for long-distance regional travelers, such as commuters going to/from San Franciscoand San Jose. These routes typically include major interchanges (i.e., between two freeway facilities).Caltrans and the CHP, as state agencies, would be in charge of implementing these alternate routes.

Local alternate routes focus on the local traveler and were developed for each freeway segment betweentwo interchanges (on-ramp and off-ramp). When a major freeway incident occurs between two freewayinterchanges, an alternate route would divert traffic off the freeway at the nearest upstream exit and onto aparallel arterial. Traffic then would be directed around the incident location using local streets toward thenext downstream freeway on-ramp. The routes also were selected to manage and minimize impacts ofdiverted traffic on the local street network. In many instances, multiple alternate route options wereidentified for one incident location.

In some situations, due to the severity of the incident or the amount of potential queue build-up on themainline, it may be advisable to implement the alternate route further upstream and connect severalalternate routes together. The concept of “stitching,” or connecting multiple route plans together, will bean option for responding to dynamically increased queuing on the freeway.

The following table, in Appendix A of the Guide, represents the alternate route planning process that wasused to develop the Guide:

Table 1. Alternate Route Planning Process (Appendix A)AlternativeRouteSelectionSelect, evaluate,and determineoptimal alternateroutes. Establishcriteria forselecting routes.Identify routes.

- Able to accommodate all vehicle types (width, height,turning restrictions)

- Sufficient capacity to accommodate diverted traffic- Ease of access to/from, easy to navigate, safe- Close proximity to freeway (primary route); lowest traveltime

- Pavement conditions- Current traffic conditions/LOS (diverted traffic should nothave “worst” traffic)

- Number of signalized intersections, stop signs, unprotectedleft turns

- Ability to control signal timing- Avoid residential streets, if possible- Consider impacts on hospital, schools, etc- Availability of ITS

- Map withpreferredalternative routes

- Stakeholdersconsensus


Table 1. Alternate Route Planning Process (Appendix A)DevelopAlternativeRoute PlanDetermine thelevel ofinformation toinclude in thealternate routeplan.

- Type of information to include in plan- Traffic related information for alternative route streets- Traffic operations information and timing plan- Outline of implementation activities, including equipmentand personnel deployment

- Provide decision criteria for law enforcement officials /incident commanders

- When alternative routes will be implemented, when toterminate

- Information to include on map (e.g., written directions;location of traffic signals, traffic control devices, signs(CMS/EMS); ITS equipment; geometric, location ofpolice/fire dept, etc.)

- Traveler information plan (CMS, HAR); layout of signs- Guidelines for deciding when to implement (e.g., duration ofincident, number of lanes blocked, time of day)

- Implementation flow chart, decision criteria- Evaluate performance of an alternative route during itsoperation

- Inclusion of contacts list

- Plan with detailedmaps andguidelines forimplementingalternative route

TrafficManagementPlanningDetermineinformationdisseminationmethods tonotify and guidemotorist alongalternativeroutes.

- Determine traffic control measures- Utilization of traffic control officers, signage (temporary andpermanent) on primary route and alternative route.

- Roles of stakeholders involved in disseminating info- Traveler information sources such as CMS, HAR, 511,media for traffic info

- Install permanent infrastructure (e.g., route markers, sign

- Plan definingtrafficmanagementstrategies forimplementingalternative routes

InteragencyAgreement /MOUDocument thatacknowledgesStakeholders’commitment tothe alternativeroute plan.

- Agreement between all Stakeholders- Include response protocols between agencies- Commitment of agencies to cooperatively work together onpolicies and strategies

- Identify agencies roles and responsibilities

- Final Agreement /MOU signed byall stakeholders


EvaluationMethodsforPerformanceMeasures:During a major freeway incident on US 101, Caltrans operators at the D4 TMC implement signal timingplans and activate trailblazer signs along the appropriate ARTI route(s) and notify the local agencies thatthe management of the alternate route(s) is in effect. In addition, traffic signal timing modifications wereimplemented in 2009 to manage traffic that exits the freeway during incidents.


Figure 9. ARTI Traffic Management Communication Diagram


GeneralGuidanceofAlternateRoutePlanPer the 2009 Traffic Incident Management (TIM) Self-Assessment (SA) Guide developed by the UnitedStates Department of Transportation (USDOT), measures to improve traffic flow in areas affected by theincident and on alternate routes include:

Real-time management of traffic control devices (including ramp meters, lane control signs, andtraffic signals) in the areas where traffic flow is affected by the incident; and

Designating, developing, and operating alternate routes.

The 2010 Best Practices in Traffic Incident Management document developed by the USDOT providesguidance on various components of alternate route planning, including the following:

Alternate Route Signal Timing – In the absence of a regional traffic signal control system, the use ofalternative or modified traffic signal timing plans during incident events can effectively improve trafficflow by providing additional green time along designated alternate routes. Most traffic signal controllersallow multiple programs to be set. Response personnel can override the normal program manually, or insome cases, the timing may be set remotely from a TMC. Alternate route signal timing plans can bedeveloped in conjunction with alternate route plans. Incident management personnel in Redding, CA,Baltimore, MD, and Camden, NJ, reported using alternative traffic signal timing plans and consistentlyrated their effectiveness in reducing excess delay as “moderate” to “high.”

When large numbers of diverted vehicles attempt to merge onto an alternate freeway or back on the samefreeway downstream of an incident, regular ramp meter timing may create long queues, which may spillback onto local streets. Most ramp-metering controllers allow either queue override or queue adjustmentto flush the queue and allow vehicles to enter the freeway. Queue override temporarily suspends rampmetering, while queue adjustment temporarily increases the metering rate to allow more vehicles to enter.

Alternate Route Planning – When a major incident occurs that severely limits roadway capacity,motorists will naturally find ways to divert around the incident. Some regions have chosen to formallyestablish alternate routes to direct traffic to the routes that are best suited to handle this increased trafficdemand. If a region chooses to implement alternate routes, it is critical that all agencies affected by theimplementation and operation of alternate routes be involved in every step of the planning and operationof those diversion plans. Diversion practices are also discussed in detail in the National CooperativeHighway Research Program Synthesis 279, ‘‘Roadway Incident Division Practices’’ (NCHRP 2000).

Alternate Route Operations and Real-Time Control – When an incident occurs that results in trafficdiverting to other routes, whether as a result of using a planned diversion route or because motorists choseto continue their trip on a less congested route, measures should be taken to manage the increased trafficon alternate routes. The existing traffic control plan should be adjusted to accommodate the divertedtraffic. This may include the following:

Use variable message signs and highway advisory radio (HAR) to disseminate information on theincident or to direct traffic to the most appropriate alternate route.


Adjust ramp metering rates to account for changes in traffic flows.

Adjust signal timing to account for changing traffic conditions.

Since freeways and arterial streets typically are operated by different agencies, personnel from theagencies responsible for operating these traffic control devices will need to implement the changes. Closecooperation and collaboration in these situations usually is facilitated by early planning efforts andongoing interaction.

Operational Procedures – The operational procedures of implementing alternate routes must bedeveloped to meet the needs of individual regions. The typical chronology of establishing alternate routesincludes the following steps:

Determination that an alternate route should be implemented

Identification of the most applicable preplanned alternate route

Notification of noninvolved agencies that will be affected by the alternate routes

Modification of traffic signal timings on alternate routes

Activation of traffic control devices and traveler information sources

Monitoring of the alternate routes

Communication with noninvolved agencies affected by alternate routes that the routes’ use isabout to be terminated

Termination of the use of the alternate routes

Uncertainties Associated with Alternate Route Planning and Operation – There are severaluncertainties associated with events that affect incident management and alternate route planning andoperations, including:

The actual duration of the incident cannot be accurately predicted.

There is no effective way in practice to achieve a theoretical optimum diversion from an openfreeway. When drivers are allowed to make their own choice based on the advisory messagesdisseminated to them through traveler information systems (uncontrolled and elective), diversiontransportation professionals have very little control over how many drivers actually divert.

The routing of vehicles that are diverted cannot be accurately predicted. Specifically, not alldiverted vehicles will return to the freeway, as some drivers will choose to complete their trip onthe arterial network once they have been diverted from the freeway. Many of the drivers who arewilling to divert will pursue routes other than the designated diversion route to complete theirtrip.


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