a collage of eight photos showing a stakeholder meeting, people boarding a bus, a changeable message sign displaying the message race traffic, cars traversing a roadway where barricades delineate travel lanes, a closed-circuit television camera, a crowd of people standing near a train and traversing a pedestrian overpass, two implementation plans, and three traffic management team personnel gathered around a laptop computer

Managing Travel for Planned Special Events

Chapter Six. Traffic Management Plan
Page 6 of 9

Traffic Flow Plan

Overview

The preparation of a traffic flow plan represents a required preliminary step to the design of a traffic control plan. The traffic demand analysis component of a feasibility study indicates the freeway/arterial corridors and local streets that event patrons will utilize to access the venue site area. In developing a traffic flow plan, the event planning team modifies predicted flow routes to maximize transportation system operating efficiency on the day-of-event while meeting public safety agency needs. In turn, a traffic control plan facilitates traffic flow on recommended flow routes through service-enhancing strategies and tactics that handle forecasted event traffic demand on these routes.

The advantage of developing a traffic flow plan is two-fold:

Allows the event planning team to influence and control event patron patterns of ingress and egress. This improves transportation system operations and reduces the impact to neighborhoods surrounding the event venue.
Provides important advance information for event patrons and participants regarding best access routes to the event. These directions provide event patrons, particularly those not familiar with the region, an increased level of comfort when traveling on the day-of-event. Event patrons also recognize that the traffic management team will sign, staff, and prioritize flow on designated routes. Non-attendee transportation system users benefit by gaining advance notice of event-designated traffic and transit routes.

Information Requirements

Table 6-21 lists various sources of data and information that drive the traffic flow plan development process. Key points that should be considered include:

Table 6-21. Traffic Flow Plan Information Sources
Source
Market area analysis Regional directional distribution Traffic demand analysis Local directional distribution Day-of-event traffic demand Site access and parking plan Parking area assignment Road closures required for event staging Street use event Public safety agency requirements Emergency access routes Transit agency requirements Scheduled and event service

A traffic flow plan should accommodate background traffic flow in addition to transit service, which will be promoted as an event patron travel alternative.
Recommended traffic flow routes should not traverse or intersect emergency access routes, if possible.
Event mandated road closures refer, in particular, to street use event parade and race routes. If not already designated, the event planning team should first determine the street use route.
- Table 6-22 provides a general checklist for evaluating the impact of closing one or more adjoining street segments, while Figure 6-29 shows a parade staging area.
- Typical staging areas include off-street parking areas and cross streets adjacent to the parade route.
- Upon reviewing the street closure checklist, the event planning team should consult with community interest stakeholders and public safety agencies in order to identify all concerns and solicit input.

Table 6-22. Road Closure Impact Checklist⁽¹²⁾
Element	Provision
One-way street operation	Does not significantly disrupt traffic operations on adjacent one-way streets.
Impacts on access	Does not have an adverse impact on: Public safety agency station access Hospital access Local resident neighborhood access Public facility access (e.g., schools, parks, etc.) Access to places of worship Access to local businesses Heavy vehicle access Public transit access
Parade staging area	Provide sufficient area for parade staging.
Coincidence with roadway construction	Does not conflict with existing roadway construction activities.
Proximity to major traffic generators	Has no adverse impact on nearby major traffic generator (e.g., shopping center, entertainment venue, etc.).
Presence of alternate routes for local access	Has available alternate routes for local access. Width of traveled-way and number/designation of travel lanes Traffic control (e.g., traffic signals and signs) Street signage Restricted traffic movements Presence of impeding traffic calming devices

photo showing a group of parade participants congregating on a residential road and intersecting road

Figure 6-29. Parade Staging Area

Another key information component concerns the identification of roadway capacity deficiencies or bottleneck locations. This includes freeway weaving areas, freeway ramp junctions, freeway/street lane-drops, and intersection traffic control. Bottleneck locations yield a constant rate of flow (e.g., saturation rate), and appropriate traffic control strategies can temporarily alleviate the bottleneck on the day-of-event by increasing saturation flow rate. Consult the feasibility study roadway capacity analysis results or conduct new analyses to evaluate operations on traffic flow routes not previously considered. In addition, practitioners should consider driving, and creating a video/photo log, of proposed traffic flow routes, emergency access routes, and transit routes. This activity assists in verifying computer analysis results and facilitating off-site event planning team evaluation of recommended routes.

Strategic Route Planning

The traffic flow plan must account for two types of traffic flow routes: corridor and local:

Corridor flow routes include the freeways and major arterial roadways serving the planned special event venue.
Local flow routes traverse the street system adjacent to the event venue and service a particular parking area or pick-up/drop-off point.
A target point represents the point of connection between corridor and local flow routes, characterized by a freeway interchange or major arterial intersection.
- In the driver's mindset, reaching a target point during event ingress signals entrance into the local area surrounding the event site. At this point, the driver anticipates receiving information and directions on event parking and pick-up/drop-off areas.
- During event egress, the driver's objective involves reaching the nearest target point (e.g., freeway interchange) in order to access a familiar corridor flow route leading toward home or some other destination.
Figure 6-30. Corridor Target Points (Graphic courtesy of Dover Motorsports, Inc.)
On the day-of-event, the management of corridor flow routes typically involves surveillance and dissemination of traveler information regarding target point and local flow route operations. The traffic management team implements traffic control initiatives beginning at the target point and continuing along the local flow route.
- Figure 6-30 displays a traffic flow plan that indicates, for reference by event patrons, various target points for access to individual venue parking areas.

Table 6-23 indicates general considerations for developing traffic flow routes. Figure 6-31 shows one corridor flow route spawning, via two target points, three local flow routes destined to the same venue access point. The figure demonstrates how a traffic flow plan works to assure that traffic demand on the existing street system adjacent to an event venue does not exceed capacity on the day-of-event if signed and staffed appropriately.

Table 6-23. Traffic Flow Route Development Considerations
Consideration
Focus on ingress and egress operations separately. Avoid left-turn movements across traffic flow. Divert traffic flow routes from critical locations (e.g., other flow routes) that could create congestion. Develop multiple local flow routes, connected to one corridor flow route, as necessary to achieve optimum traffic distribution on the roadway system. Assign local flow routes to contingency overflow parking areas identified in the site access and parking plan.

a road map shows three traffic flow routes from a freeway to a stadium

Figure 6-31. Multiple Local Traffic Flow Routes (Graphic courtesy of the City of San Diego.)

Figure 6-32 describes a process for assessing corridor and/or local traffic flow routes. Traffic control strategies for increasing corridor route capacity include eliminating weaving areas or other ramp control tactics. Strategies for local routes include striping additional travel lanes to handle flow in the predominant direction, restricting turning movements, and revising traffic signal timing plans. The "Traffic Control Plan" section of this chapter describes these strategies and other mitigation alternatives in greater detail.

a flowchart illustrating a process for assessing corridor and/or local traffic flow routes

Figure 6-32. Traffic Flow Route Assessment Process D

Aside from parking contingencies and the occurrence of severe congestion on the day-of-event, practitioners should maintain and promote the same flow routes identified in the traffic flow plan. These routes are generally pre-signed and communicated to event patrons and participants prior to the event. Measures of effectiveness for evaluating the performance of designated traffic flow routes, in additional to corresponding traffic control strategies, include: (1) time to regain free-flow operations and (2) time to clear parking areas.

Alternate Routes

The deployment of an alternate route plan marks a key traffic management strategy for minimizing the effect of non-recurring congestion, caused by a traffic incident or event-generated traffic demand, on traffic flow. It serves to reduce demand at a traffic incident site or bottleneck through the diversion of traffic from the mainline to parallel freeways, arterials, and streets. As part of traffic incident management efforts, some jurisdictions may maintain alternate route plans for freeway and arterial segments traversing a region.

An alternate route plan represents a contingency plan that stakeholders should consider developing for corridors serving a planned special event venue, where high-speed crashes or cargo spills may block travel lanes for a long duration. In other instances, an alternate route plan becomes a critical component of the overall event traffic management plan when roadway or bridge construction activities limit the capacity of mainline corridor flow routes. Transportation system operators should also promote travel choice alternatives, such as using other travel modes, as an option to driving alternate routes.

The process of developing alternate route plans and procedures for plan deployment requires a group endeavor involving all affected agencies, most of which likely comprise the event planning team and/or traffic management team. Table 6-24 lists the steps required in developing an alternate route plan. Practitioners should consult NCHRP Synthesis 279, Roadway Incident Diversion Practices, for state-of-the-practice information about the development and deployment of alternate route plans.⁽¹³⁾ Table 6-25 highlights numerous considerations in alternate route plan development, all of which are addressed in the cited synthesis report.

Table 6-24. Alternate Route Plan Development Process
Step
Identify mainline bottleneck or problem locations. Evaluate proposed alternate routes. Determine appropriate criteria for plan deployment. Achieve participating agency agreement on roles and responsibilities. Identify equipment and personnel resources required to deploy an alternate route plan. Establish guidelines for plan evaluation and updating.

Table 6-25a. Alternate Route Plan Development Considerations: Alternate Route Selection
Item	Consideration
Stakeholder Roles and Coordination	Advance planning stakeholders and stakeholders involved in alternate route deployment Interagency agreements for advance planning and/or operations
Types of Alternate Routes	Freeway, street, and toll facility Secondary alternate routes
Inventory Potential Alternate Routes	Access, capacity, vehicle restrictions, traffic control, background traffic, pavement conditions, road geometrics, percentage of heavy vehicles, transit accommodation, and available surveillance Considerations in rural, urban, and metropolitan areas
Alternate Route Evaluation	Capacity analysis and modeling Traffic signal timing optimization
Alternate Route Selection Criteria	Road user and community impacts

Table 6-25b. Alternate Route Plan Development Considerations: Alternate Route Plan Development
Item	Consideration
Alternate Route Plan Map	Incident location limits, direction of routed traffic, ramp/street closures, traffic control resources, alternate route distance and capacity, alternate route regulations and restrictions, and emergency service stations
Traffic Control Requirements	Traffic control officers, temporary signs, and barricades
Criteria for Alternate Route Plan Deployment	Incident duration, number of lanes blocked, time of day, etc.
Deployment Operations Plan	Checklist for field supervisor and communications center supervisor

Table 6-25c. Alternate Route Plan Development Considerations: Road User Accommodation
Item	Consideration
Motorist Information Resources	Pre-trip and en-route Message sets Planned media release
Traffic Management on Alternate Route	Permanent trailblazers Technology applications

photo showing a police cruiser parked in the middle of a two-lane arterial, and two traffic control officers directing traffic to turn onto an alternate route

Figure 6-33. Background Traffic Diversion

The effectiveness of deploying an alternate route plan revolves around the accommodation of diverted traffic along the alternate route. It is essential that the diverted traffic encounter an equal or higher level of service on the alternate route compared with that on the mainline. As shown in Figure 6-33, alternate route plan deployment, particularly plans developed specifically for a planned special event, typically requires significant law enforcement resources for alternate route traffic management and operations surveillance. Technology applications for managing traffic on an alternate route, and reducing field personnel requirements, include the installation of dynamic route guidance signs controllable from a transportation operations center. Figure 6-34 shows a dynamic trailblazer sign. During the program planning phase, stakeholders managing recurring planned special events at permanent venues should evaluate the need for installing these devices along commonly used alternate routes serving the event venue.

Emergency Access Routes

Emergency access route planning involves designating street closures within the venue site area to connect the some or all of the following termini: (1) public safety (e.g., fire and emergency medical service) headquarters, (2) local hospital, (3) freeway or major arterial serving a regional hospital, and (4) location of staged ambulances and first-aid stations for on-site medical treatment.

photo showing a dynamic blank-out sign, mounted on a mast arm above a sign stating "alternate route – when arrow on," displaying a pull-through arrow

Figure 6-34. Dynamic Route Guidance Sign (Photo courtesy of the Minnesota DOT.)

For large-scale planned special events, emergency access routes remain closed to all non-emergency vehicles. Traffic control officers staff each intersection along the route and permit side street traffic to cross the route when conditions permit. For smaller-scale special events, the emergency access route denotes a local flow route for emergency vehicles that may be utilized by general traffic under non-emergency conditions. Under an emergency scenario, law enforcement officers may escort emergency vehicles, using a rolling roadblock, via the designated access route. Emergency access routes should not traverse or intersect event patron traffic flow routes to/from the event venue and associated parking areas.

The provision of emergency access lanes along streets slated for closure in order to stage a planned special event allows unimpeded emergency vehicle access throughout the entire local street network impacted by the event. This particularly applies to street use event routes. Typical specifications for an emergency access lane involve delineating a 20 foot wide, paved curb lane within the existing roadbed (e.g., shoulder plus traveled-way).

Background Traffic Accommodation

The composition of background traffic, or non-attendee motorists, traversing streets and highways in the vicinity of a planned special event venue include the following categories:

Regional through traffic
- Includes truckers and intra- or interstate travelers represent regional through traffic.
Local through traffic
- Includes commuters and area residents, some of whom may simply cruise local streets adjacent to the event.
Neighborhood residents and businesses
- Includes residents living in the immediate vicinity of the event venue that may incur impacts attributed to high traffic demand and temporary traffic control strategies.
- Includes nearby businesses requiring accommodation for both employees and patrons.

Table 6-26 presents a range of passive (e.g., traveler information dissemination only) and aggressive (e.g., physical traffic control) tactics for accommodating background traffic during a planned special event.

Table 6-26. Tactics for Accommodating Background Traffic during Planned Special Events
User Group	Tactic	Benefit
Regional through traffic	Freeway-to-freeway diversion beginning a significant distance upstream of an event venue	Maintains mobility. Reduces the level of background traffic on corridor flow routes serving the venue.
Local through traffic	Arterial-to-arterial diversion	Eliminates non-attendee exposure to venue site area. Discourages cruising around site area. Allows public to become familiar with route after repeated implementation.
Neighborhood residents and businesses	Parking restrictions	Permits resident access to on-street parking spaces. Permits employee and customer access to public parking areas.
Neighborhood residents and businesses	Traffic control points	Restricts neighborhood area access to residents and business employees.
Neighborhood residents and businesses	Signing and alternate routes	Directs customers to businesses and other traffic generators.

Freeway-to-Freeway Diversion

Transportation management system operators can implement freeway-to-freeway diversion through control of permanent changeable message signs and highway advisory radio.

Parking Restrictions

Parking restrictions accomplish the task of preventing event-generated traffic from deviating from local event traffic flow routes and traversing neighborhood residential and commercial areas.

Traffic Control Points

Road closures may impact customer access to businesses and other traffic generators. Figure 6-35 shows a sign diverting traffic destined to a major traffic generator located adjacent to a planned special event temporary venue.

photo showing a police cruiser and Type 1 barricades blocking one roundabout approach, and a guide sign, located in a roundabout gore area, stating "alternate route to aquarium parking"

Figure 6-35. Accommodation of Traffic Destined to Major Generators

Large-scale events may generate sufficient traffic demand to saturate the entire local street system adjacent to the event venue, causing undue congestion and blocking neighborhood access and circulation patterns. If this represents a potential concern during advance planning, then locate event parking areas a sufficient distance away from affected neighborhood areas and create traffic control points to prevent event-generated traffic from penetrating these areas. Residents and business employees would receive a pass allowing them access through the traffic control points.

Arterial-to-Arterial Diversion

Arterial-to-arterial diversion applies to planned special events occurring in city downtown or commercial areas, where arterials and local streets adjacent to the event venue serve a significant volume of background traffic. In turn, the addition of event-generated traffic causes congestion and impacts commercial businesses (e.g., restaurants, hotels, retail stores). This tactic involves: (1) restricting commercial street access to businesses employees, customers, emergency vehicles, taxis, and transit buses and (2) deploying an alternate route to direct background through traffic and event-generated traffic around the restricted street.

Planned special event stakeholders in Atlanta, Georgia developed such an alternate route, entitled the "Blue Loop" to divert traffic away from restricted Peachtree Street during special events in downtown Atlanta.⁽¹⁴⁾ Stakeholders prepared the plan during the program planning phase in response to lessons learned from past planned special events that occur in the Atlanta downtown area and generate significant automobile traffic. They hope the term "Blue Loop" becomes an alert that city residents will recognize and understand that the alternate route is in effect. Traffic monitoring represents a key to Blue Loop operation, and the route deployment detail specifies several release points for diverting Blue Loop traffic to adjacent highways.

Street use events involving a parade or road race permit the traffic management team to reopen certain roadway sections after event participants pass, even if the event has not completed. Background traffic accommodation includes disseminating specialized traveler information, summarized in Table 6-27, prior to the event. The information provides non-attendee transportation system users a timeframe, relative to the parade/race pace and field length, that certain route sections will be closed. Otherwise, travelers may mistakenly assume that the entire street use event route will remain closed for the duration of the parade or road race.

Table 6-27. Pre-Trip Traveler Information for Street Use Events
Item
Indicate the entire parade or race route coupled with participant staging and disbanding areas. Estimate, based on the event pace and length of the field, and specify times each roadway segment and intersection will be closed and reopened. State other traffic and parking restrictions in the vicinity of the event course. Organize information for easy reference using maps and reference numbers (for intersections and roadway segments).

Transit Accommodation

A traffic management plan that prioritizes bus flow to and from the venue site area positively influences the utility associated with transit and other travel choices involving express bus, charter bus, or shuttle bus transport. Transit agencies should operate on scheduled bus transit routes up until the last possible point to divert around a road closure required to stage a planned special event. This avoids user confusion and minimizes inconvenience to non-event attendees.

Table 6-28 lists tactics for accommodating scheduled and event-generated bus service.

Table 6-28. Bus Accommodation Tactics
Tactic
Exclusive bus route Exclusive/priority bus lane On-demand communication with TMC or command post

Exclusive Bus Route

Exclusive bus routes that cause a negligible impact to background traffic and adjacent neighborhoods represent the recommended bus accommodation tactic. Advantages of exclusive bus routes include: (1) use of the same route during ingress and egress, (2) increased mobility and travel time reliability, and (3) better venue station accommodations for riders as temporary stations may exist adjacent to bus routes, thus avoiding conflicts with event vehicle and pedestrian traffic.

Depending on roadway network layout, a special event traffic flow plan may feature an exclusive bus route from corridor target points and satellite parking areas direct to designated pick-up/drop-off areas adjacent to the venue. Other bus routes may only divert buses around known bottleneck locations. Figure 6-36 shows an exclusive bus route implemented for a major rural planned special event. An exclusive bus route must accommodate minimum overpass height requirements, vehicle weight requirements, and vehicle turning radii.

photo showing two buses traversing a local road

Figure 6-36. Exclusive Bus Route

Exclusive/Priority Bus Lane

An exclusive bus lane represents a travel lane for bus traffic only. Temporary applications include converting an existing roadway shoulder or travel lane for bus use during a planned special event. Table 6-29 summarizes drawbacks associated with the temporary operation of an exclusive bus lane. A bus priority lane is used by both buses and general traffic between intersections. However, at intersection approaches such as that shown in Figure 6-37, regulations limit general traffic to a turning movement, while buses can continue straight through the intersection and "jump" adjacent through-lane queues.

Table 6-29. Exclusive Bus Lane Limitations
Limitation
Lane may obstruct access to mid-block driveways. Mid-block turning movements may create queues in adjacent through travel lanes. Congestion may occur upstream of the lane start, especially if the lane utilizes an existing travel lane. Shoulder lane use may eliminate area for emergency stops. Manned intersection control may be required to allow buses and cars to turn in front of the other. Maintenance of signs and lane delineators are necessary. Special enforcement requirements are needed.

photo showing a sign, located adjacent to a right-turn lane on multi-lane intersection approach, stating "right lane must turn right – bus exempt"

Figure 6-37. Bus Priority Lane

On-Demand Communication

On-demand communication with a command center represents another bus accommodation tactic that the traffic management team may employ in conjunction with other previously discussed tactics. Bus operations supervisors or other traffic management team personnel, stationed at the TMC or event command post, monitor roadway surveillance sources (e.g., CCTV and field observers) in order to identify areas of congestion before a bus encounters it. When supervisors verify a traffic bottleneck affecting a bus route, they immediately notify bus operators and work to divert buses around the congested area.

Plan Specifications

The traffic flow plan serves stakeholders managing the planned special event in addition to event patrons and participants. The product of strategic route planning involves informing event patrons of best access routes to and from the planned special event. Stakeholders can communicate preferred route directions via: (1) event patron ticket mailings, (2) media public information campaigns, and (3) event, venue, or traffic information websites.

Table 6-30 contains a traffic flow plan development checklist.

Table 6-30. Traffic Flow Plan Checklist
Element	Provision
Event patron corridor flow route	Indicate recommended freeway ramps, by route direction, to/from event venue or specific parking area. Indicate corridor target points representing a connection to local flow routes. State freeway or arterial lane assignments for event traffic (e.g., event traffic two right-lanes). Furnish information on roadway construction projects, as applicable, and indicate alternate routes. Indicate modified ramp control tactics (e.g., closures/additional lanes). Show freeway interchange configurations (and direction of travel) and exit numbers. State tolls, if applicable.
Event patron local flow route	Show connection to corridor flow route. Indicate local streets that connect to freeway entrance/exit ramps. Indicate recommended flow route to/from general and reserved parking areas (minimum) or individual parking areas (recommended). Indicate one-way streets. Show all road segment closures. Specify permitted turning movements. Emphasize controlled turn areas (turns prohibited or only one turn allowed). List modified roadway striping (e.g., reversible lanes or contra-flow). Indicate event participant/VIP access routes.
Traveler information	Promote use of regional park & ride locations and event satellite parking areas. Indicate commercial radio and highway advisory radio frequencies with event travel information. Alert motorists of static and changeable message sign guidance along route. Stress importance of following route and adhering to traffic control officer instructions.
Traffic management team information	Include contingency maps detailing routes to overflow parking areas. Provide written directions for diverting corridor flow routes via local street system. Indicate alternate routes for ingress and egress to same target point.
Other travel modes / user groups	Show transit routes and state corresponding route number(s). Show preferred taxi routes. Indicate bicycle routes. Indicate pedestrian routes.
Other considerations	Provide information on both ingress and egress flow routes. Emphasize law enforcement endorsement of recommended routes and directions. State travel times (by mode of travel) and distances (e.g., from select origins) State when special traffic flow routes go into effect and terminate. Disseminate written ingress/egress driving directions. Indicate potential points of confusion ("do not take") along recommended route (e.g., freeway exits, turning movements). Indicate heavy vehicle restrictions. Indicate expected congested/non-congested areas. Use callouts to highlight critical movements. Label all streets and freeways. Color-code recommended routes to specific parking areas. Emphasize new provisions (e.g., new road closures or route). Prepare maps for different venue events if parking plan varies. Show parking areas. Show venue gates. Draw map to scale. Show private property. Display landmarks.

Appendix I contains example traffic flow maps prepared for various planned special events.⁽¹⁵⁾

Traffic flow plans should emphasize available express, charter, and shuttle bus services from regional park and ride lots and/or satellite parking areas. Driving directions should be accompanied by useful travel tips that coincide with the day-of-event operation of recommended traffic flow routes. Travel tips include accessing en-route traveler information and adhering to traffic control tactics.

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