Traffic Signal Management Plans
Chapter 3. How to create the Traffic Signal Management Plan
Involve the Appropriate Stakeholders or Staff
The most appropriate staff to have input to the development of a traffic signal management plan (TSMP) will vary depending on the size of the organization and the manner in which its activities are structured. Typically staff with responsibility for the design, operations, or maintenance of the traffic signal system will be involved in developing the TSMP. This may include the following:
The champion of the TSMP should be the senior person responsible for successful operation of the traffic signal system. This person has an interest in the performance of the traffic system as it is impacted by traffic signal timing, an interest in the standard of maintenance, and an interest in good signal design, modification or replacement at an appropriate time.
The champion within the agency may be supported by internal staff and/or by a qualified consultant with experience in strategic planning, operations, maintenance and/or systems engineering in order to develop the document.
Scale and Scope of the Document
Deciding on the appropriate scale of the activity and scope of the document will depend on its intended use and on the current state of your signal program. Research suggests that in the majority of agencies, operations capability tends to be immature (largely relying on individuals using ad hoc procedures to time signals), while design and maintenance tend to be more advanced (with more formalized procedures and checklists). Overall the design, operation, and maintenance activities often occur in silos, with the result that needs, resources, and capabilities often do not align satisfactorily. An agency with many ad hoc processes might initially use the TSMP to develop, or identify the need for, documented processes.
If an agency currently operates on a largely ad hoc basis that is intended to initially concentrate on formalizing the planning, execution, and performance measurement of maintenance activities, the initial plan can be relatively small. However, if an agency is well organized and the purpose of the plan is largely to formalize current practices and to facilitate and provide a training and succession plan that will continue successful operation beyond the tenure of existing staff, then it is likely that all sections will be required. For succession planning in an agency with well documented processes, the TSMP might document connections of regional and agency goals to traffic signal program objectives.
Within a State agency, it may be appropriate to have a statewide TSMP, or a separate one for each district. In a smaller agency in which signal timing is handled by the maintenance organization, then the senior technician may be the most appropriate "owner" of the TSMP.
Based on experience with several test groups, development of the TSMP typically requires one or two half-day meetings to develop a consensus on the issues, goals, and objectives, followed by several months of activity by a staff member(s) and/or consultant. These case studies have also shown that an agency should set its expectations for the TSMP at a realistic level that initially represents an improvement over its current situation, and not try to develop a fully comprehensive TSMP at the outset. The starting point should begin at the existing level of capability, so that plans and processes move gradually from ad hoc to documented, documented to measured, and measured to optimized.
Support is also available from FHWA’s Resource Center. Staff can provide resource materials, such as an annotated outline for a TSMP, can review draft TSMP's and provide content advice, and may also be able to facilitate training workshops for groups that are sufficiently large. Useful materials may also be found on FHWA’s website at: https://www.fhwa.dot.gov/resourcecenter/teams/operations/
Obtain Appropriate Levels of Approval
A TSMP should be approved and/or endorsed by the chief executive of an agency. This ensures the support of decision-makers and budget approvers for the activities covered by the TSMP. It also ensures that those activities will be consistent with the plans and programs of other units of the agency.
There are two different but completely acceptable approaches to developing a TSMP, illustrated in Figure 6. The classic planner approach is top down, which involves progressively developing the GOST statements, starting with goals, which are informed by the agency’s vision and policy, and working down to tactics. Within agencies that do not have well-documented processes, it is likely that a top-down approach will be necessary to formulate objectives, strategies and tactics that are consistent with agency goals. The second approach, often more understandable to traffic signal operators, is bottom up. It involves describing the strategies and day-to-day tactics that are used and then describing in turn the objectives that are being achieved by using those tactics and mapping them to the agency goals that are satisfied by those objectives.
Often, the most difficult part of the process is to elicit objectives that are stated in a way that is meaningful to traffic signal management, yet clearly consistent with the agency’s overall goals and transportation objectives. You must be careful to avoid stating objectives for which the performance measures are not associated with traffic signal management or operation.
For example, an agency's objective related to bicycle safety and mobility may be to "…provide safe and efficient bicycle facilities to and from all major activity generators." However, this could be addressed through many avenues that do not specifically involve traffic signals, such as bike paths, exclusive bike lanes on arterials or parallel roads, shared facilities away from arterials, as well as specific treatments for bicycles at traffic signals. A more focused objective suitable for traffic signal management could be to "…safely and efficiently accommodate all bicycles at all traffic signals." This could lead to specific strategies to be applied at traffic signals (such as detecting bicycles and providing appropriate safety timing when bikes are present) and specific metrics that will determine the extent to which that specific objective is being met through traffic signal management.
Both approaches may be necessary for the assembly of a TSMP. It is easiest for practitioners to start from the bottom by documenting the day-to-day activities (tactics) and work up to the strategies and objectives. It helps to put context around what an agency does. Then go to the top and find the goals and objectives of the agency and work down to the strategies.
The hardest part of this process tends to be developing clear and concise objectives that are actionable and measurable. An agency's planning documents often have statements about vision, goals, objectives, guiding principles and policies that begin at a lofty level and the action plans developed in those documents often sound like statements of objectives to traffic signal operators. An agency should expect that the objectives it creates based on current strategies and activities will likely not match the level of the objectives statements often found in planning documents, as illustrated in Figure 7.
At some point the objectives will be consolidated into those relevant to the traffic signal system and then the strategies need to be reviewed. Working both from the bottom up and the top down helps to identify if there are any holes in the strategies and tactics. You will able to identify if there are goals not being supported by strategies or if there are activities that don’t support the goals and objectives, as illustrated in Figure 7.
The following steps provide an outline of the process that may be used to create and adopt a TSMP. The actual process you use should be tailored to suit the size of your organization, the extent to which other agencies will participate in the development process and eventual implementation of the plan, and the key people who are championing the plan. A very important early step is to set out the proposed process and have as many stakeholders as possible commit to following the process before you embark on it.
The intent of the TSMP is to align the activities that are being done to operate and maintain the traffic signal system with objectives and the overarching goals of your agency. As shown in Figure 7, instead of starting with the goals and objectives and working down to the strategies and tactics, the process begins by documenting the activities currently performed by the traffic signal staff (step 1) in each area of the traffic signal program (maintenance, design, operations and management and administration. These activities represent tactics, and it is often easiest to begin by documenting maintenance activities, followed by design and then operations, management, and administration. The process then work its way up to strategies by requiring planners first to ask themselves why each activity is performed (step 2a), then to create an initial set of objectives that could be supported by those strategies. Rather than developing goals at this point, these will be extracted from existing sources (step 3a and 3b).
The initial strategies will be revised (step 5) and expressed in a way that clearly supports the objectives. This may also involve revising the tactics to add new tactics to fill apparent gaps or removing tactics that (while perhaps being of some use) are not necessarily supporting any defined strategy. Some iteration may be necessary between steps 2, 4 and 5. In step 6, evaluation methods and strategies will be selected, and the full TSMP will then be compiled (step 7).
Figure 8 depicts a flow chart of the process. As can be seen, the operator approach and planner approach run parallel to each other.
Step 1 – Document Activities
Step 1 starts with the operator in mind and begins with the tactics. Write down the activities that staff currently do related to the maintenance, design or operation of the traffic signal system. The list of activities should include any activity performed on some recurring basis. An activity could occur annually, be a daily function, or be something that is only done when a specific event or situation occurs. This list will result in your system strategies and tactics. Use this as the basis for a brainstorming session in order to identify all activities. It is also critical to list activities that are contracted out. This list can also include a reference to existing policy documents and procedures you follow (maintenance checklist, signal timings guidelines, etc.), instead of repeating the detailed tasks within each procedure.
It may be helpful to group the activities into three groups: maintenance, operations, and design. By doing this, the staff involved in each of the categories can provide input on their specialty. There may be overlap between the different groups—this is okay. The duplications will be condensed later. The list will most likely contain a mixture of strategies and tactics—this is okay also. Tactics are "what" you do and strategies are "how" you do it, and at times it is difficult to draw the line between them.
The following questions are meant to help you document your activities, by organizing them around the typical categories associated with traffic signal system management. The questions are not all encompassing and your agency may do things not listed here. You can also review job descriptions for your staff to ensure all activities are captured.
Traffic Signal Maintenance
Multimodal safety and efficiency
Management and Administration
Budgeting and programming
Step 2a – Describe Related Strategies
Based on the items listed in Step 1, think of the reasons why the agency conducts these particular activities. The answer will typically give you the strategy you are implementing through this activity. For example:
What do you do?
Tactic: Modify signal timing temporarily to compensate for equipment failures (e.g., stuck detector)
Why do this?
Strategy: Respond to citizen complaints
Step 2b – Develop Objectives
For each strategy described in Step 2B pose the question: what are we trying to achieve by implementing that strategy? This will identify the objectives that you have for all the activities you undertake. For example:
What do you do?
Tactic: Modify signal timing (stuck detector)
Why do this?
Strategy: Respond to citizen complaint
What are you achieving?
Objective: Maintain operational efficiency of signal system or ensure that traffic signals provide equitable service to all users.
Step 3a – Identify and Link to Agency Goals
Step 3 starts with the planner in mind by reviewing your agency's planning documents as shown in step 3a. Identify the goals listed in a transportation system plan, transportation chapter of a comprehensive plan, area plan, congestion management plan, etc. Goals from the transportation system plan or the goals of the transportation division of an agency work well since they directly relate to the transportation system. Goals from an agency general plan (for example) tend to be broader or high level and relate more to the overall function of the agency. It may be more challenging to pull out transportation related goals. If your agency doesn’t have documented goals from planning documents, then you will need to develop your own goals for the signal system.
Transportation goals extracted from the City of Walnut Creek General Plan 2025 (Walnut Creek, 2006) are listed in Table 5. Each of the transportation goals is reviewed to determine whether or not it is relevant to traffic signal management. Those that are relevant are then carried forward, along with any related objectives that are documented.
Source: City of Walnut Creek
Step 3b – Review Transportation Objectives
Some agencies adopt guiding principles or policies to explain the context within which their objectives are framed. In one agency's General Plan, numerous policies were described, intended to support each goal, and at the same time providing a mixture of objectives and contextual guidance. Each of these can then be assessed to determine whether or not they are relevant to traffic signal management.
The transportation policies established in the example General Plan, and an assessment of their relevance to traffic signal management, are contained in Table 6. These can be used to guide the description of traffic signal management objective in the next step.
Some agencies have adopted objectives for the different departments (including public works, engineering, transportation, etc.). If this is the case, review and compile the Objectives that relate to the traffic signal system. If your agency doesn't have documented objectives from planning documents, then you will need to develop your own objectives for the signal system.
Source: City of Walnut Creek
Step 4 – Consolidate Objectives for Traffic Signal Management
Combine, review, and distill the Objectives developed in Step 2 and the Objectives from Step 3b. Now that you have described objectives that could be supported by your strategies, you should modify them and define them in a manner that is consistent with the transportation objectives identified in Step 3. These should be expressed in terms that would work for both the operator and the planner. Example TSMP objectives that have been derived using this process are contained in Table 7. For example, the TSMP objective of "operate traffic signal system at its maximum efficiency within the context of a balanced, multimodal operation, as described in current operational policies" was established to accommodate several of the agency's transportation objectives, namely:
Step 5 – Rationalize Strategies to Support Traffic Signal Management Plan Objectives
At this point you have a set of traffic signal management objectives that are consistent with your agency's transportation goals and objectives. Most of these objectives will be supported by the strategies you described in Step 2. You should now review and revise the strategies so they clearly support your revised TSMP Objectives developed in Step 4. At this point, you may choose to reword the strategies and tactics for consistency, add to them, or consolidate them. This may involve further editing the objectives to ensure that strategies you consider important are not discarded because they were not linked to an appropriately worded objective.
If you can't clearly describe an objective that would justify employing a specific strategy, you should seriously consider dropping that strategy, because it cannot be justified within the context of your TSMP. This review process also provides the opportunity to confirm that all the stated tactics are, in fact, legitimately supporting your objectives. At this point, you may need to consider dropping a tactic (even a long-standing activity) if you cannot show that it is actually supporting your objectives and is consistent with your listed strategies. Now look at the objectives brought forward from Step 4 and identify any that are not yet support by strategies and tactics. If you have any, create additional strategies what will support those objectives. You may choose to identify those strategies in your action plan for future implementation.
One way to verify that the strategies and tactics are meeting the objectives is to develop a traceability matrix. To do this, start by listing your goals and objectives, organized in a way that shows which objectives support which goals. Then for each objective, list all the strategies that support each objective. It is quite likely that some strategies will support more than one objective, so you should list those several times, under each relevant objective. Each strategy is supported by one or more tactic or activity, and each tactic may support one or more strategies. You should now list each tactic that supports each strategy. As before, this may involve listing some tactics multiple times.
Table 8 shows example goals, objectives, strategies and tactics that have been developed in TSMPs by UDOT, City of Walnut Creek and City of South San Francisco.
Now you need to work upwards from objectives to goals, and also work downwards from goals to objectives. This will help you align the activities with your agency’s goals, and provide a basis for enunciating goals that have not been adequately documented so far, but are needed to clearly show justification and support for all the activities.
This then provides a vehicle for detailed reconsideration of what you do, why you do it, and will potentially lead in three different directions:
Step 6 – Develop Evaluation Methods
In Step 6 you select evaluation methods, measures and metrics that will allow you to assess both operational success (you are impacting traffic operations as desired) and implementation of strategies (you are effectively doing what you agreed to do). At this point, you have all the necessary elements to compile your TSMP (step 7). Within this document, we define performance measurement as the process of assessing the effectiveness of the traffic signal system in providing the desired traffic operational performance, and how well the objectives have been satisfied. This is measuring the outcomes. We define implementation verification as the process of measuring the activities undertaken by the team and determining to what extent the strategies and tactics have been implemented. This is measuring the outputs. For your operational Objectives, determine the performance measurement that is most appropriate to monitor performance. (See Chapter 4 for more information on selecting performance measures, determining data, and tracking performance of your system.)
It is best to start with one or two performance measures and build upon them as your system becomes more mature. Examples of performance measures, related directly to the operational objectives implement by City of Mesa, City of Walnut Creek and UDOT, are including in Table 9. In each of these, a single measure of performance was chosen as a determinant of success in meeting an objective. For example, an objective defined by the City of Mesa a decade ago was to provide stable travel times on specified corridors. They defined stability as limiting annual increases in average travel times to be in proportion to the changes in traffic volumes. The travel times were initially measured using floating car surveys on an annual schedule, repeating the surveys during the same week of the year. In recent years, travel times are now measure automatically and continually using Bluetooth readers, providing both a larger sample size and coverage of all periods of the day and days of the week, to allow better evaluation of the performance against the stated objective.
Step 7 – Traffic Signal Management Plan Assembly
Now it is time to put the TSMP chapters together. Refer to the proposed Outline of Chapters in the next section to see how to compile the document. Feel free to modify this layout, just as long as you keep the intent of mapping the strategies to your agency's goals.
United States Department of Transportation - Federal Highway Administration