Traffic Signal Operations and Maintenance

Staffing Guidelines

Prepared by:

  

Dunn Engineering Associates, P.C.

in cooperation with  

Kittelson and Associates, Inc.

Prepared for:

Federal Highway Administration

Washington, D.C.

March  2009

FHWA‐HOP‐09‐006
NOTICE

This document is disseminated under the sponsorship of the U.S. Department of Transportation in the

interest of information exchange. The U.S. Government assumes no liability for the use of the information

contained in this document. This report does not constitute a standard, specification, or regulation. The U.S.

Government does not endorse products or manufacturers. Trademarks or manufacturersʹ names appear in

this report only because they are considered essential to the objective of the document.

QUALITY ASSURANCE STATEMENT

The Federal Highway Administration (FHWA) provides high‐quality information to serve Government,

industry, and the public in a manner that promotes public understanding. Standards and policies are used

to ensure and maximize the quality, objectivity, utility, and integrity of its information. FHWA periodically

reviews quality issues and adjusts its programs and processes to ensure continuous quality improvement.
1. Report No. 

FHWA-HOP-09-006 

2. Government Accession No. 3. Recipient’s Catalog No.

5. Report Date: March 2009 4. Title and Subtitle

Traffic Signal Operations and Maintenance Staffing Guidelines 

6. Performing Organization Code 

7. Author(s)

Robert Gordon (Dunn Engineering), Cade Braud (Kittelson and 

Associates) 

8. Performing Organization Report No.

 Project 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

Dunn Engineering Associates 

66 Main St. 

Westhampton Beach, NY 11978 

and 

Kittelson and Associates

225 East Robinson Street, Suite 450 

Orlando, Florida 32801 

11. Contract or Grant No.

Contract No. DTFH61-06-D-00005

13. Type of Report and Period Covered

Final Report 

Jan 2008 – March 2009 

12. Sponsoring Agency Name and Address

U.S. Department of Transportation 

Federal Highway Administration 

Office of Operations 

1200 New Jersey Ave, SE 

Washington, DC 20590

14. Sponsoring Agency Code

HOP 

15. Supplementary Notes

Eddie Curtis, Contracting Officer’s Task Manager, FHWA. The project team acknowledges, Paul Olson, 

FHWA Resource Center the Puget Sound Regional Operations Committee and the numerous 

practitioners that provided key information to develop this report. 

16. Abstract

This report provides a guideline to estimate the staffing and resource needs required to effectively 

operate and maintain traffic signal systems. The results of a survey performed under this project, as 

well as a review of the literature and other surveys indicated that agencies achieving a high level of 

signal system performance do so under a wide variety of conditions such as agency size, geography, 

system complexity and traffic conditions that do not adhere to the typical level of documented resource 

requirements. Accordingly, a set of performance-based criteria were developed to define requirements. 

The performance-based criteria are focused on establishing realistic and concise operations objectives 

and performance measures. 

17. Key Words

Signalized Intersections, Traffic Signal Timing, Staffing, Traffic 

Signal Operations, Maintenance, Management, Objectives, 

Performance Measures 

18. Distribution Statement

No Restrictions. 

19. Security Classification. 

Unclassified 

20. Security Classification. (of this 

page) Unclassified

21. No. of Pages

84 

22. Price

 N/A 

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

            Page 

Executive Summary .................................................................................... 1 

About This Document .................................................................................... 2 

1. Guidance for Operations and Maintenance Objectives and Performance 

Measures .................................................................................... 3 

1.1 Introduction .................................................................................... 3 

1.2 Definition of Objective Oriented Operation (OOO).......................... 5 

1.3 Conclusions and Recommendations .................................................. 17 

 1.3.1 Management Approach.......................................................... 18 

 1.3.2 Functionality .......................................................................... 18 

 1.3.3 Staff Qualifications, Training and Experience ...................... 19 

2. State of the Practice .................................................................................... 23 

 2.1 Literature Survey ............................................................................... 23 

 2.2 Field Survey .................................................................................... 30 

 2.2.1 Overview................................................................................ 30 

 2.2.2 Definition of Traffic Signal System Management, Operation 

 and Maintenance .................................................................... 31 

 2.2.3 Survey Distribution and Respondents.................................... 32 

 2.2.4 Classification of Signal System Characteristics .................... 33 

 2.2.5 Staff Levels and Qualifications.............................................. 37 

 2.2.6 Maintenance Practices ........................................................... 39 

 2.2.7 General Observations............................................................. 40 

 2.3 Operations and Maintenance Staffing and Resources ....................... 41 

 2.3.1 Introduction............................................................................ 41 

 2.3.2 Resource Requirements for Traffic Engineering ................... 42 

 2.3.3 Cost of Signal Retiming......................................................... 43 

 2.3.4 Resource Requirements for Maintenance Personnel ............. 43 

 2.4 Evaluation of Agencies Relative to CITS Criteria............................. 45 

 2.4.1 Evaluation of Agencies Surveyed.......................................... 45 

 2.4.2 Overview of Current Practices............................................... 48 

 2.4.3 Relationship of Agency Practices to Objective Oriented 

 Operation (OOO) ................................................................... 49 

Appendix A – Questionnaire ..................................................................................... A-1 

Appendix B – Survey Responses............................................................................... B-1 

Appendix C – Frequency of Signal Retiming............................................................ C-1 

Appendix D – North Central Texas Council of Governments Ranking Model......... D-1 
1

EXECUTIVE SUMMARY 

This report provides a guideline to estimate the staffing and resource needs required to 

effectively operate and maintain traffic signal systems. In 2007, the NTOC Traffic Signal 

Report Card (TSRC) assigned a grade of D nationally to how agency programs support the 

efficient operation and maintenance of traffic signals (5). The D grade indicates that relative to 

what is considered “good practice”, overwhelmingly an ad-hoc approach is taken, resulting in 

some positive outcomes, but generally agency programs are not as effective as they could be. 

In surveys of practitioners and national experts completed by the FHWA, it was recognized that 

no clear definition of traffic signal operations has been developed and no consensus appears to 

exist as to what activities are required to support traffic signal operations. The lack of a concise 

definition of traffic signal operations provides some insight into why practices, staffing levels, 

objectives and performance measures are divergent in this area. Operating agencies clearly 

understand the requirements for adequate traffic signal maintenance. The results of several 

surveys indicate that many agencies tend to be primarily focused on maintenance activities, with 

most of their attention focused on keeping traffic signals operating (turning green, yellow and 

red) and little attention on making the operation efficient on a 24/7 basis. This has some safety 

implications and contributes to millions of hours of unnecessary traffic delays and congestion. 

A working definition of traffic signal operations is the active prioritization of objectives and 

collection of information to efficiently manage traffic signal infrastructure and control devices to 

maximize safety and throughput while minimizing delays. The working definition of traffic 

signal maintenance is the preventative and responsive activities to preserve traffic signal 

infrastructure and control devices necessary for the safe and efficient utilization of arterial, 

collector and local roadways. The discussion of resource requirements in this report will refer to 

the definitions of traffic signal operations and maintenance as stated above. 

Initially, it was envisioned that this report would verify and update the resource requirements

(staffing levels and criteria or levels of staff experience and training) provided in a number of 

publications including the ITE Traffic Engineering Handbook and FHWA Traffic Control 

Handbook. The results of a survey performed under this project, as well as a review of the 

literature and other surveys indicated that agencies achieving a high level of signal system 

performance do so under a wide variety of conditions such as agency size, geography, system 

complexity and traffic conditions that do not adhere to the typical level of documented resource 

requirements. Accordingly, a set of performance-based criteria were developed to define 

requirements. The performance-based criteria are focused on establishing realistic and concise 

operations objectives and performance measures. The operations objectives and performance 

measures dictate the staffing and resource level required for their achievement. 

Research indicated that while maintenance was, in general, timely, and that agencies used 

effective tools such as Synchro to develop signal timing plans, significant deficiencies resulted 

from a failure to systematically determine the need for signal retiming and to retime at 

appropriate intervals. This result is closely related to not clearly establishing and documenting 

specific operations objectives and programs to measure performance. 
2

Key management and operations criteria and recommendations to attain effective traffic signal 

operations and maintenance include: 

• Management controls. Staff qualifications and periodic updating of management plans. 

Management plans should include a mission statement, strategic plan, objectives and 

measures, periodic collection and review of performance data and remedy of deficiencies 

in signal timing and other system characteristics. Recommendations concerning 

communication paths with the public and other stakeholders are also described. 

• Signal timing design. Signal timing performance should be reviewed at periods 

established by management plans but should not exceed 30 to 36 month periods. Signals 

should be retimed using an accepted methodology. A methodology for determining the 

number of daily timing plans required as well as weekend and special function timing 

plans should be utilized. 

• Operations. Functional changes in requirements such as pedestrian needs, transit and 

preemption requirements, etc. should be periodically reviewed and addressed. Criteria are 

provided for the persistent monitoring of traffic systems. 

• Maintenance. Since maintenance response time for failure repair after the agency has 

been notified of failure is generally good and the ability to automatically detect failures at 

isolated intersections is poor, a criterion to improve this capability was established. 

Recommendations for the up-time for detectors are provided. 

The report provides recommended personnel staffing, training and experience levels. 

ABOUT THIS DOCUMENT 

The audience for this document is agency managers, practitioners and personnel seeking to gain 

an understanding of the resource requirements to effectively and efficiently operate and maintain 

traffic signals. The document is organized into two major sections Guidance and State of the 

Practice. The Guidance section is advisory and is intended to provide a methodology for 

identifying operations and maintenance objectives and performance measures as well as for 

estimating staffing and resource needs required to achieve the specific operations objectives. 

The guidance is supported by an in depth survey, conducted for this project, of a limited subset 

of agencies that participated in the 2007 NTOC Traffic Signal Report Card Self Assessment 

Survey. A review of literature, discussions with noted experts, and a synthesis of surveys 

conducted by the FHWA Resource Center Operations Technical Service Team during Traffic 

Signal Operations Reviews, which characterize the state of the practice. 

The State of the Practice section documents literature reviewed, the survey conducted to gather 

information for this project and a synthesis of information collected from other surveys. The 

appendix provides the methodology executed to develop the conclusions that are presented as 

guidance. 
3

1. GUIDANCE FOR OPERATIONS AND 

MAINTENANCE OBJECTIVES AND PERFORMANCE 

MEASURES

1.1 INTRODUCTION 

The objective of this section is to provide a guideline to assist managers and practitioners to 

prioritize the operations and maintenance objectives and performance measures to evaluate 

staffing and resource needs required to effectively operate and maintain traffic signal systems. 

Ineffective operation and maintenance of traffic signals may have safety implications and 

contributes annually to millions of hours of unnecessary traffic delays, congestion, fuel 

consumption and air pollution. The issues associated with understaffing and under funding 

traffic signal system operation and maintenance, activities are indigenous to urban, suburban and 

rural areas. 

Major contributors to the inconsistency found in traffic signal operations and maintenance 

budgets include: 

• A lack of clear guidelines describing traffic signal operations and maintenance 

activities and the resources required to support these activities; 

• The lack of documented objectives and performance standards; 

• Funding mechanisms that are geared more towards project development than 

operations and maintenance. 

Some effort has been made to provide a benchmark for, and to promote good traffic signal 

operations and maintenance practices through the National Traffic Signal Report Card and 

associated self-assessment survey. These efforts have been supplemented through traffic signal 

operations audits and traffic signal operations reviews conducted by the FHWA. In 2005, the 

National Traffic Operations Coalition (NTOC) assigned a national grade of D- to traffic signal 

operations and maintenance practices. In 2007, the National Traffic Signal Report Card (5) 

grade improved slightly to a grade of D. The agencies that improved their scores employed 

“more effective management techniques and are taking a more thoughtful approach to resource 

allocation.” (6) 

While the Traffic Signal Report Card evaluates conformance to what is considered “good 

practice” it does not define traffic signal operations or maintenance. Clearly defining traffic 

signal operations and maintenance are essential to beginning the discussion about staffing and 

resource needs to support these functions. The following working definitions are offered for 

traffic signal operations and maintenance as a result of surveys conducted by the FHWA 

Resource Center and a glossary of terms developed by the Transportation Research Board 

Regional Transportation Systems Management and Operations Committee. 
4

Traffic signal operations is the active prioritization of objectives and active collection of 

information to efficiently manage traffic signal infrastructure and control devices to maximize 

safety and throughput while minimizing delays. 

Traffic signal maintenance includes the preventative and responsive activities to preserve traffic 

signal infrastructure and control devices necessary for the safe and efficient utilization of 

arterial, collector and local roadways. 

Under a given set of geometric conditions, and without budgetary, technological and knowledge 

constraints the expectation of a minimum delay or ideal traffic signal system might be 

achievable. The goal of achieving an ideal traffic signal system, while unachievable given 

current constraints, should nonetheless represent the desired level of traffic system operation. To 

bring reality to the situation the ideal traffic signal system must be constrained to obtain goals 

that are Specific, Measurable, Achievable, Realistic and Timely (SMART). This requires clearly 

asserting objectives that are realistic given the resources available. 

Past approaches to development of resource and staffing criteria for operation and maintenance 

of traffic signals have often provided guidelines in terms of the number traffic signals that can be 

maintained and operated per number of personnel performing these tasks. These approaches do 

not adequately consider the how agencies view their role, operations objectives and desired level 

or needs for traffic signal management operations and maintenance. Responsible agencies differ, 

in many characteristics. Some of these key variables include: 

• Number of signals and changes in number of signals 

• Variations in knowledge, skills and abilities of maintenance and engineering personnel. 

• Differences in functions that the systems and agencies must perform. 

• Organizational structure of the responsible agency (sharing of resources with other 

functions) and budgeting structures. 

• Geographic configuration of traffic flow network i.e. grid, arterial and the overall number 

and size of other facilities in the transportation network (freeways, interstate, transit, 

freight, land use etc.) 

• Density of traffic signal network relative to population density. 

• Congestion levels. 

• Type of signal system (e.g. distributed or centrally controlled); distribution of signals on 

the network and need for interconnection. 

• Procurement of maintenance (own forces vs. contract). 

• Procurement of signal timing plans (own personnel vs. consultants). 

• Institutional issues such as union issues (e.g. union vs. nonunion employees, particularly 

as they relate to contractors.) 
5

With this large number of variables, and because agencies provide essentially the same types of 

services in many different ways, it is essential that agencies develop a set of operations and 

maintenance objectives that are consistent with the agencies traffic management philosophy. 

The objectives should be SMART and defined in terms of performance, reliability and function 

(PRF) based criteria (as compared with resource based criteria.) 

The following five key elements have been identified to serve as a basis for developing objective 

based criteria: 

• Management 

• Design 

• Operations 

• Maintenance 

• Training 

• Section 1.2 defines these elements and describes the Objective Oriented Operation 

(OOO) requirements for these elements. The Management element describes a set of 

candidate objectives, a subset of which may be adopted by the agency. Section 1.3 

provides detailed conclusions and recommendations developed during the study. 

1.2 DEFINITION OF OBJECTIVE ORIENTED OPERATION (OOO) 

A. Management

Traffic signal operation is one of the transportation industry’s most visible services provided to 

the traveling public. Therefore, it is appropriate that top management and elected leaders be 

attentive to and supportive of good traffic signal operations. Outlining and documenting a 

management approach for traffic signal operations is very important. Committing the appropriate 

resources (staff, funding and attention), coordinating activities, communicating with the traveler 

and cooperating and integrating with others are all important management activities (5). 

Management practices for OOO should include the following: 

1. Supervision of traffic operations by a PE and/or PTOE. 

2. Availability of a mission statement and annual review. The mission statement contains a 

set of agency objectives. A listing of representative objectives from which the agency 

objectives may be developed is shown in Table 1.1. A set of representative measures is 

also included in the table. The measures selected by the agency should incorporate the 

following features: 
6

• The measures should span the traffic system and agency functions required 

without significant redundancy. Be sufficiently general to encompass the 

different requirements of all agencies. 

• Be measurable or answerable using existing information, information which can 

be readily obtained or information that may take some effort to collect but which 

is vital to the determination of the capability of the traffic system relative to the 

OOO. 

• Minimize the need for subjective judgment to accomplish evaluation.

3. Collect and analyze data for traffic system measures selected for the mission statement. 

Management plans should incorporate a documented methodology for this analysis 

including a recommended time interval for reviews. The time interval should reflect 

traffic conditions, the type of network and the data collection capability of the traffic 

system. The interval should not, however, exceed 30 to 36 months. Continuous automatic 

data collection and subsequent data mining may assist in developing the database for the 

analysis. These measures primarily serve to identify trends in performance to provide a 

comparative basis for year-to-year evaluations. Based on these measurements and other 

requirements, a plan for required physical upgrades of the signal system or changes in the 

approach to signal timing and phasing should be developed. While many measures may 

be considered, a limited set that can be readily measured are the most useful. For systems 

whose mission is to provide basic signal control, a representative set might include: 

• Delay. 

• Travel time. 

• Crash analysis (13,14) 

• Intersection level of service. 

• Approaches worse than Level of Service F (control delay exceeding 80 seconds 

per vehicle). 

4. Development and analysis of traffic system reliability data on an annual basis. 

5. Availability and annual review of a Concept of Operations. Changes in functional 

requirements such as the need for preemption, transit priority, diversion timing plans 

and evacuation signal timing plans should be included in the review. 

6. Compliance with the Regional ITS Architecture requirements pertaining to traffic 

systems. 

7. Availability and annual review of a strategic management plan. The plan should have 

both long-range and short-range components. It should provide for the review and 

updating of the traffic system plant, engineering, operating and maintenance personnel 

requirements and purchased services. It should review the design, operations, 
7

maintenance and training items described below. The review should be approved by the 

director of the operating agency. The management plan should be shared with employees. 

8. Capability should be available for easy communication with the motorist. Examples 

include a well-publicized telephone call-in capability and an email response capability on 

the agency’s web site. 

9. Regional traffic signal operations should be established to ensure that timing plans are 

coordinated with those of neighboring agencies. The management approach should also 

consider coordination with neighboring agencies to respond to incidents and to both 

planned and unplanned events.
8

TABLE 1.1 

EXAMPLES OF OBJECTIVES AND MEASURES FOR TRAFFIC SIGNAL SYSTEMS

OBJECTIVE EXAMPLES MECHANISM TO ACHIEVE OBJECTIVE POSSIBLE MEASURE POSSIB

MOBILITY, FUEL CONSUMPTION AND EMISSIONS 1. Reduce delay and fuel consumption for normal traffic patterns. Signal retiming should improve delay and fuel consumption by a specific minimum amount each time retiming is performed. 

a. Improved signal timing. b. Improved level of traffic system 

control (e.g traffic responsive, traffic adaptive) 

c. Real time adjustment of timing 

by operator. 

d. d. Improved maintenance 

response time. 

a. Vehicle hours delay. b. Gallons fuel reduced. c. Monitoring and tracking of 

citizen complaints, (provide regional 311 or equivalent phone number for reporting) 

a. Travel Tb. Traffic sd. Simulat

independprogramsdata for in

e. Real tim

monitorin

a. Signal timing – items a, b, c in 1 above. Same as 1. Simulation

2. Reduce delay and fuel consumption for incident conditions and special events. New signal timing plans to support these functions should improve delay and fuel consumption by a minimum of 2% when these plans are in effect. 

b. Support of incident management using CCTV and other information. 

Same as 1. Simulation 

incident cle

3. Reduce emissions. Same as 1. Kg of CO, NOX, SO2, CO2. Derive from 
9

OBJECTIVE EXAMPLES MECHANISM TO ACHIEVE OBJECTIVE POSSIBLE MEASURE POSSIB

SAFETY 4. Reduce crashes resulting from left turns, red-light running and signal outages. Improvement measures should result in a 1% reduction in accidents. 

Improved maintenance response time. Implementation of countermeasures to reduce crashes due to left-turns and redlight running (13,14). 

Crashes reduced. Analysis in

using resprecords. 

5. Reduce secondary crashes resulting from incidents. Improvement measures should result in a 2% reduction in secondary accidents. 

Support of incident management using CCTV and other information. 

Secondary crashes reduced Analysis in

using reduclearance 

COMMUNICATION WITH PUBLIC AND PUBLIC PERCEPTION OF SERVICE 

• Achieve other objectives. • Regular reporting to 

public 

6. Improved public perception of Rating scale. Survey. signal and management center operations by 1% per year. 

Monitoring and tracking of citizens complaints (provide regional 311 or equivalent phone number for reporting) Develop and provide outreach material describing how traffic signals function and the benefits of active operations. Develop website to disseminate information and reports, provide an online feedback and complaint database. 

Number of calls, complaints Monitor nu

respond to complaints 
10

OBJECTIVE EXAMPLES MECHANISM TO ACHIEVE OBJECTIVE POSSIBLE MEASURE POSSIB

7. Provide traffic information to public and private traffic information services. Improved information quality and delivery by 1% per year 

Make traffic, construction, special event, incident, weather data and CCTV signals available to traffic services, media, web sites. 

Rating scale. Survey. 

ANCILLARY FUNCTIONS 8. Serve as a diversion route for corridor operations. Goal established by stakeholders. 

b and c in 1 above plus availability of diversion timing plans. 

Same as 1 and 3. Corridor si

9. Provide preemption for emergency vehicles and railroads. Goal established by stakeholders. 

Preemption equipment.. Use of equipment must be carefully restricted so as not to cause unreasonable delay to general traffic 

Number of critical mission emergency vehicles provided preemption. 

Some preeprovide loggranted. 

10. Provide transit priority. Goal established by stakeholders. 

Priority equipment used for late vehicles. 

Traveler hours reduced. Variation in delay reduced 

Transit recsimulation variation c

11. Support emergency evacuations. Goal established by stakeholders. 

Evacuation signal timing, phasing, and lane use plans. 

Availability of plans. 

MANAGEMENT 12. Data for planning and evaluation. 

Mining of detector data Employment of data by agency or 

MPO. 
11

OBJECTIVE EXAMPLES MECHANISM TO ACHIEVE OBJECTIVE POSSIBLE MEASURE POSSIB

13. Improve internal efficiency of department operations. 

Plans and procedures, training, concept of operations and operations procedures documents. 

Development of review processes to consider traffic signal operations and maintenance from planning to design and construction. 

Time to plans. 
12

B. Signal Timing Design

Traffic signal coordination is one of the most important aspects of good traffic signal operation on 

arterials. Signal coordination ensures that motorists are able to travel through multiple intersections at 

a prescribed speed without stopping or with an absolute minimum of stops (5). 

Regardless of whether an individual signalized intersection is coordinated with other nearby signals 

or operates totally independently, there are issues that are critical to how well that intersection 

operates and serves the public. Reviewing and updating the intersection-specific timing and 

operational aspects of individual signalized intersections on a regular basis is extremely important, 

especially where changes in traffic volumes and/or adjacent land uses have occurred since the last 

review. The issues include reviewing and updating the phasing sequence, detectors, displays, timing 

parameters and other related operational aspects of individual signalized intersections within a 

jurisdiction (5). 

Signal timing design practices should include the following: 

1. Review of intersection performance data every three years to determine whether 

geometric improvements can remedy approaches exceeding 90% saturation for 200 

hours per year on weekdays and 100 hours per year at other times. 

2. Review of intersection performance data for phasing and type of signal control 

(actuation, etc.) 

3. Review of signal timing performance using a documented methodology should be 

performed at periods established by management plans but should not exceed 30 to 36 

month periods to identify the need for retiming (see Appendix C).1

 Where 

automatically collected data is available, it should be reviewed at 6 month intervals to 

determine the need for more rapid retiming. A methodology to establish the priority 

of retiming requirements should be used (for example see Appendix D). 

4. Retiming of signals should be performed as part of this review cycle. Data should be 

collected as necessary to support the retiming process. Timing plan updates should be 

performed using an accepted methodology such as SYNCHRO, TRANSYT 7F, etc.

Retiming should be completed and checked in the field within 3 months of identifying 

the need for retiming. 

5. Retiming should be supervised by a PE/PTOE. 

6. A methodology for determining the number of daily timing plans required as well as 

weekend and special function timing plans should be utilized. Factors such as 

saturated approaches, spillback from intersections and turning bays should be given 

                                                     

1

 These criteria may be modified where agencies utilize adaptive systems or ACS Lite type systems. 
13

special attention. Strategies that facilitate flow during light traffic periods should 

likewise be given attention. 

C. Operations 

Agencies should support operational practices that have been shown in the past to be effective. 

Operations should include the following: 

1. Supervision of traffic operations by a PE and/or PTOE. Supervision should include 

periodic review and assessment of continuing operations and counseling employees on 

improving operations. Other supervisory monitoring activities include periodic review of 

automatically collected data and physical observation of traffic operations. 

2. The data collected in Signal Timing Design Items B.3 and B.4 should be reviewed to 

develop a plan for required physical upgrades of the signal system. System upgrades 

should be accomplished in accordance with the Strategic Management Plan (Item A.7.) 

3. A plan for remedying reliability deficiencies identified in item A.4 should be developed. 

Correction of major deficiencies not requiring major capital expenditures should be 

performed within three months. 

4. Changes in functional requirements such as the need for pedestrian treatment, preemption, 

transit priority, diversion timing plans and evacuation timing plans should be identified 

and a plan developed for their implementation. 

5. Commitment to continuing education for the professional staff. 

6. Traffic systems in urban or suburban areas that are of a medium size or larger should 

provide a capability to monitor real time field information at a central facility for the 

majority of signals. Manual monitoring should, as a minimum, be provided during 

weekday peak periods and at such additional times as conditions may require. Smaller 

systems should be periodically monitored during these periods. Monitoring should 

include equipment failures and unusual congestion conditions. The operator should select 

alternate signal timing plans when conditions such as incidents or special operations 

require. A criterion and process should be employed to establish appropriate monitoring 

periods. 
14

D. Maintenance 

Maintenance practices should include the following: 

1. Response time - Response time depends on two factors - time to obtain an indication of 

failure and time to respond after receiving an indication of failure. The following 

requirements apply: 

• Time to obtain indication of failure – Since closed loop systems and other centrally 

monitored systems provide an indication of controller failure, rapid failure 

identification can be accomplished using such techniques if these systems are 

supervised. Criteria for the percentage of failures that are initially detected within the 

traffic agency (as compared to reports from police, other agencies or citizens) are: 

o For systems in excess of 400 intersections 70% of failures should be detected 

by the operating agency. In a dense network of coordinated signals, critical 

failure detection by the agency should approach 100%. 

o For systems with 400 intersections or fewer, 50% of failures should be 

detected by the operating agency. Detection should be considerably higher for 

a dense network 

• Time to respond after receiving an indication of controller or signal failure. 

o Within one hour during business hours. 

o Within two hours during non-business hours. 

The Traffic Signal Report Cards indicate that a significant number of agencies conform to 

this requirement. 

A procedure to identify the level of criticality for the intersection with respect to safety 

and congestion should be developed. Response priorities should be developed in 

accordance with this procedure. 

2. Rates of critical failures (e.g. controller failures, deficient cabinet or signal wiring, short 

circuits, lightning strikes, etc.) should not exceed F failures per year per for each 

intersection. Where this rate is exceeded for a period of one year, an investigation to 

determine the root cause should be conducted. To establish the value of F, intersection 

failure rates should be reviewed and the value of F set at the highest 20% of intersection 

failure rates. 

3. Spares for the current equipment in the field should always be available. 
15

4. A minimum of 95% of the detectors in the system should provide the system functions to 

the accuracy required for the application at any time. 

5. Qualifications for technicians for maintenance performed by the agency or by their 

contractor are described in Table 1.2. Although the specific technician position titles 

differ among agencies the table provides a spectrum of requirements for commonly used 

technician grades. 

6 Periodic checks of database parameters and controller settings should be performed. 

Procedures for software program and database configuration control should be adopted 

and utilized. Backups for software and databases should be maintained.
16

Table 1.2 

Recommended Qualifications for Maintenance Personnel

Requirement Technician 1 Technician 2 Maintenance 

General Tasks 

Replacement and repair of controllers, signals, wiring and other field equipment. Works under direction. 

Skills include programming of traffic controllers, troubleshooting controllers and ancillary equipment. Requires minimal direction. Provides direction and training to Technician 1 level. 

Full supervisory responsibilTechnician 1 and Techniciatechnical knowledge than TAdministrative duties includsupplies, contract administrprovision for training. 

Education and Experience 

• High school 

(minimum). 

• Knowledge of 

electrical standards, codes, practices and repair techniques. 

• Certification to IMSA 

Traffic Signal Level I within one year of employment. 

Minimum of 2 years as Technician 1 plus: 

• Certification to IMSA Traffic 

Signal Level II. 

• Minimum of two years 

experience as Technician 1. 

• Combination of tra

experience for a toyears. 

• Certification to IMS

II. 

• Additional training 

Signal Level II. 

Physical Requirements 

• Must be able to work 

for long periods in inclement weather. 

• May be required to lift 

heavy objects, work from bucket trucks 

Same as Technician I. 
17

E. Training 

Training practices should include the following: 

1. A plan to insure that the required number of qualified personnel will be available when 

required. The plan should prepare for retirements and other personnel losses. 

2. Support for training programs to achieve personnel proficiency requirements including 

the education required for continued PE and PTOE certification. 

3. Support for specialized training provided by suppliers and others relating to specific 

equipment or software currently in use or planned. 

Formation and participation in a statewide or regional traffic signal management program should 

be considered. Regional traffic signal management programs allow agencies to formulate 

operations objectives that serve both the regional and local needs, facilitate consistent traffic 

signal operations throughout the region and provide a collective voice to improve the resources 

available for traffic signal operations and maintenance. 

1.3 CONCLUSIONS AND RECOMMENDATIONS 

As stated by the National ITS Architecture Traffic Signal Operations is a strategy to manage the 

travel demand and flow of traffic on an arterial or roadway, At the beginning of the project, the 

guidance to be provided was envisioned to be defined, in large measure, by the resources used to 

accomplish these functions. The results of the literature review and the survey did not show a 

sufficiently strong correlation between resources provided and performance to justify defining 

the guidance strictly in terms of resources.2

 During the course of the effort, it was determined 

that agencies have different approaches to the use of resources for the signal timing process and 

the primary guidance should be in terms of performance based criteria. This was termed 

Objective Oriented Operation (OOO). 

OOO satisfies the objectives of the jurisdiction with regard to providing a quality of service that 

manages delay equitably and responds in a timely way to operations and maintenance 

requirements. It provides services consistent with the objectives of the agency, regional and 

national standards of performance. Given that there is no nationally accepted standard of 

performance, the performance requirements should be generally consistent with those identified 

by the NTOC Traffic Signal Report Card, as it our best current synthesis of what constitutes 

good practice. 

                                                     

2

 The respondents estimates of detailed resource information may be in considerable error and the subjective 

character of agency performance estimates contribute significantly to this lack of strong correlation. 
18

The following conclusions and recommendations are largely based on the key items described 

for OOO in Section 1.2 and the staffing recommendations that are summarized later in this 

section and described in more detail in Section 2. It is recognized that agencies whose current 

capabilities differ significantly from these recommendations may require considerable time to 

reach this capability. It is, however, important that significant progress in this direction be made 

each year. If it is unlikely that agencies will achieve this capability in the future because their 

size is not compatible with the specialized requirements of OOO, it is recommended that other 

means, such as contract services or combining functions with another agency or jurisdiction be 

considered. 

1.3.1 Management Approach 

Agencies generally do not implement a systematic top-down approach to management. This type 

of approach requires a systematic, periodic, documented review, at least annually of the 

department’s operations and the performance of the traffic signal system. Management 

deficiencies common to many agencies as determined by the study that should be resolved 

include the following: 

• Availability of a mission statement including objectives. 

• Availability of an annually reviewed and documented strategic management plan that 

describes the available system assets and operations, plans for improvement 

(including plans to update signal timing). The strategic management plan should also 

include plans for the correction of the types of deficiencies described in this section. 

• Availability of a set of measures and periodic collection and evaluation of 

performance data relative to these measures. Mining and analysis of automatically 

collected data should be used to support this evaluation. 

• Communication paths that are easy for the public to use. 

• Resolution of issues and servicing of requirements involving other stakeholders. 

Typical requirements include signal preemption, transit priority, corridor 

coordination, coordination of signal timing with other agencies. 

1.3.2 Functionality 

Operations

Many agencies do not retime signal with sufficient frequency nor do they have a systematic 

approach to determine the number of timing plans and their operating periods. Recommendations 

to correct these deficiencies include the following: 

• Signal timing performance should be reviewed at periods established by management 

plans but should not exceed 30 to 36 month periods. Signals should be retimed using 

an accepted methodology. A methodology for determining the number of daily timing 
19

plans required as well as weekend and special function timing plans should be 

utilized.

• Review of system performance data to determine necessary phasing changes or 

intersection improvements. 

• Systematic review of the number of timing plans needed and the periods for which 

they should be employed.

• Changes in functional requirements such as the need for pedestrian treatment, 

preemption, transit priority, diversion timing plans and evacuation timing plans 

should be identified and a plan developed for their implementation. 

Maintenance

Once a notification of a critical field equipment failure is received, response times to repair are 

generally satisfactory i.e. within one hour during business hours and within two hours during 

non-business hours. Service deficiencies often occur under the following circumstances 

• Most isolated traffic signals are neither connected to a traffic control system nor is 

provision made for monitoring their failure status. As a result, notification of 

equipment failure is often considerably delayed. It is recommended that greater 

emphasis be placed on providing such feedback to the cognizant maintenance facility. 

• Most traffic control systems provide notification of critical equipment failure. It is 

recommended that when the traffic operations center is not staffed, this information 

be provided directly to the maintenance facility if the agency has not already made 

provision. 

• Traffic detector repairs are often not made with the same response time as for critical 

equipment failures. It is recommended that a minimum of 95% of the detectors in the 

system should provide the system functions to the accuracy required for the 

application at any time. 

1.3.3 Staff Qualifications, Training and Experience 

Staff Qualifications 

Providing sustained excellence in traffic signal operations requires qualified and well-trained 

 professionals throughout the operating agency. Traffic signal operations rely on expertise and 

support at all levels, from maintenance and engineering technicians to traffic engineers for 

signal operations and management. Specific job classifications vary between jurisdictions 

due to the size of the agency, number of signals operated and staffing levels. Regardless of 

the number of staff or the job classification, certain core functions must be performed to 

develop and sustain good traffic signal operations. These functions require specific 

knowledge, skills and abilities. The depth of knowledge needed varies by staff position and 

subject matter. 
20

In order to stratify knowledge, skills and abilities and to provide an organizing structure for 

the analysis of training gaps, four generic categories of traffic signal professionals were 

defined. The following are descriptions of these categories or positions pertaining to traffic 

signal operations. It is important to note that the number of positions, titles and allocation of 

responsibilities can and should vary based on agency size and needs. For very small 

agencies, the traffic engineer for signal systems and the traffic signal design engineer may be 

a single individual. In some cases, these roles or some portions thereof may be performed by 

a traffic engineering technician. Therefore, the following descriptions are illustrative, and 

vary among agencies (11). 

TRAFFIC ENGINEER 

Traffic Engineer for Signal Systems: 

This is typically a supervisory and advanced professional position responsible for 

directing the work activities pertaining to traffic engineering and operations, including 

the installation, monitoring, modification, maintenance and administration of all traffic 

signals and signal systems within the geographic boundaries of the jurisdiction. This 

position ensures that signal-related maintenance activities are adequately planned and 

executed and that there is an adequate inventory for signal related projects. The traffic 

engineer for signal systems is responsible for investigating and preparing specific 

recommendations for all traffic-related inquiries from both the public and governmental 

agencies and for providing overall traffic engineering expertise. This position plans, 

administers and supervises the installation, alteration, maintenance and repair of all types 

of traffic control devices. This position also develops and administers contracts for the 

installation or modification of traffic signal installations. 

Signal Operations Engineer: 

This is typically an advanced professional position responsible for, among other duties, 

managing, directing and supervising the planning, design, implementation, optimization 

and distribution of timing plans for traffic signal and signal system timing projects. This 

position reviews and approves plans for accuracy and clarity, conformance to standards, 

good engineering practices and reviews the provisions for the safety of the motoring 

public. Depending on the size of the agency, this position may be a supervisory position 

responsible for managing, directing and supervising assigned personnel on timing 

strategies, standards and practices for traffic signal and signal systems. The signal 

operations engineer may manage and supervise the development, approval, 

implementation and optimization of timing strategies at signalized intersections and 

signal system corridors. This position will coordinate, plan and evaluate computerized 

timing software packages. It also develops and recommends new strategies and tactics for 

traffic signal and signal system timing, including the development of performance 

criteria, methods of testing and an evaluation of performance. 
21

MAINTENANCE

Traffic Engineering Technician:

This position is typically responsible for advanced technical engineering support in the 

design of traffic signal control, communication systems and the operation of traffic signal 

systems. Depending on the size of the agency, there may be several traffic engineering 

technician positions with varying levels of expertise that correspond to designated 

technician levels. The position performs a variety of functions, including but not limited 

to the following: 

• Provides technical assistance for traffic signal design, including phasing and 

calculation of timing plans; 

• Uses computer-based software programs to develop optimized timing plans for 

individual intersections, corridors and/or networks; 

• Maintains signal timing database; 

• Maintains count database; 

• Takes and responds to calls from the public pertaining to traffic signal operation; 

• Conducts traffic signal studies; 

• Conducts field reviews of signalized operations to identify problems and/or 

adjust timing plans; and 

• Evaluates signal system operations in the field. 

Signal Maintenance Technician: 

This position is typically responsible for the installation, diagnostics and maintenance of 

all electronic equipment pertaining to traffic signal operation. Depending on the size of 

the agency, there may be several traffic signal maintenance technician positions with 

varying levels of expertise that correspond to designated technician levels. This position 

must have knowledge related to the application of sophisticated electronics and data 

communications technologies to traffic control applications, and be knowledgeable of 

new technologies applied to both new and old traffic control applications, including the 

variety of brands, models, types of equipment, systems and software that are available. 

Changes in traffic control technology and the greater use of telecommunications require 

increasingly more knowledge of electronics and greater computer literacy. The individual 

also requires sophisticated skills to troubleshoot and repair the latest generation of traffic 

electronic equipment. 

Achieving OOO functionality requires a staff capable of providing the level of services 

required or capable of supervising qualified contract personnel. In many cases, besides the 
22

courses provided by equipment and software suppliers, there is little support for or 

encouragement of training. Professional training to achieve the recommended competence 

levels should be encouraged and supported. Required proficiency levels are summarized 

below. 

• Agency management and supervision of signal timing and operations should be 

supervised by a personnel with a Professional Engineer and a Professional Traffic 

Operations Engineer qualifications. 

• Maintenance technicians should conform to the requirements shown in Table 1.2 

Staffing Levels

Achievement of OOO capability requires adequate staffing by qualified personnel. Staffing 

requirements are driven by the objectives (Table 1.1), performance measures selected and 

agency specific considerations described in Section 1.1. The following staffing guidelines are 

based on operating agencies interviewed under this project and other projects. 

• A staffing level of 75-100 signals per engineer for agencies that operate a minimum 

of 150 signals will be appropriate to support the Constrained Ideal Traffic System. 

Smaller agencies will likely require fewer signals per engineer because economies of 

scale may be difficult to realize. 

• A staffing level of 30-40 signals per technician for agencies that operate a minimum 

of 150 signals will be appropriate to support the Constrained Ideal Traffic System. 

Smaller agencies will likely require fewer signals per technician because economies 

of scale may be difficult to realize. 

Giblin and Kraft (12) estimate that a per intersection annual average of 42 hours is required for 

preventive maintenance, 15 hours for response maintenance and 3 hours for design maintenance 

for a totals of 60 hours. With an estimate of 1627 hours per year of productive time available per 

technician, they estimate that one technician can service 27 intersections. More technician labor 

is required if the agency has a greater percentage of complex intersections. 
23

2. STATE OF THE PRACTICE 

This section describes the state of the practice regarding traffic signal operations and 

maintenance. Section 2.1 provides the results of the literature surveyed. Section 2.2 documents 

the results of the field survey conducted under this project as well as relevant results developed 

under a related survey performed by the Puget Sound Regional Council (7). Section 2.3 

summarizes the operations and staffing resources required. Section 2.4 relates current agency 

practices to the requirements for achieving OOO capability 

2.1 LITERATURE SURVEY 

The following descriptions summarize key information relating to traffic operations and 

maintenance. 

TRAFFIC CONTROL SYSTEMS HANDBOOK 

This handbook provides an update to the 1996 Traffic Control Systems Handbook and covers 

traffic signal maintenance as part of Chapter 13, System Management. In this chapter, the 

authors describe the increased complexity of traffic signal systems since the previous Handbook 

update and how agencies have often erroneously estimated the maintenance requirements of 

these systems. The example given is that agencies assume that technology upgrades associated 

with traffic signal systems would result in fewer maintenance requirements and therefore under 

estimate budget and staffing needs as well as staff skill levels for them. The authors suggest that 

agencies perform a cost trade off analysis during the design of traffic signal system upgrades that 

considers the potential impacts on maintenance that follow. 

The Handbook defines three types of traffic signal system maintenance activities: Functional, 

Hardware, and Software. Functional maintenance activities include updating traffic signal 

system databases and optimizing signal timing plans. The Handbook describes hardware 

maintenance activities as remedial, preventive, or modification. Remedial hardware 

maintenance includes the immediate replacement of malfunctioning or failed equipment. 

Preventative hardware maintenance includes scheduled intervals at which equipment is checked 

to minimize failure probability. Hardware modification relates to design flaws or changes 

identified after design that are needed to improve equipment characteristics. 

For software maintenance, the Handbook describes debugging problems identified following 

system acceptance or the modification of the software to provide additional features. 

The authors identify the possible results associated with inadequate traffic signal maintenance. 

These results include a potential for increases in accidents, degraded system performance, and 

increases in equipment malfunction or failures. 
24

The Handbook also provides a summary of staffing surveys for various Traffic Management 

Centers (TMC) and their respective City/Area population, TMC, and traffic signal system sizes. 

The survey results are summarized here in Table 2.1. 

Table 2.1 

Comparison of Various Traffic Signal System TMCs in the U.S.

Location 

City / Area 

Approx. 

Population TMC Size 

Number of 

Traffic Signals 

on System Staff 

Los Angeles, CA 

(ATSAC) 

3,700,000 5500 sq ft 2912 7 transportation engineers, 

including 1 supervisor. 2 

systems analysts, 1 

graphics designer, 1 traffic 

signal electrician, 1 

secretary 

Miami-Dade 

County, FL 

2,200,000 5000 sq ft 2020 13 employees 

San Antonio, TX 1,100,000 6000 sq ft 765 1 engineer, 3 technicians 

Las Vegas, NV: Las 

Vegas Area 

Computer Traffic 

System (LVACTS) 

1,500,000 

(Covers Clark 

County) 

2500 sq ft 700 4 administrative positions. 

4 traffic operations 

positions. 4 maintenance 

positions 

Atlanta, GA 416,000 2300 sq ft 650 Traffic signal operations: 1 

engineer, 1 senior operator, 

2 operators. CCTV: 1 

engineer, 1 technician 

Albuquerque, NM 449,000 800 sq ft 450 4 employees (2 engineers) 

Seattle, WA 600,000 1420 sq ft 432 One supervisor, two 

operators 

Phoenix, AZ 1,300,000 1500 sq ft 400 1 supervisor, 4 technicians 

Denver, CO 555,000 2800 sq ft 450 No dedicated staff for TMC. 

Approx 1.5 FTE, more 

during special events 

Boston, MA 590,000 2500 sq ft 320 7-8 employees 

Renton, WA 53,000 700 sq ft 96 Initially, one part-time staff 

member. Can 

accommodate up to two 

full-time staff members 

Redmond, WA 48,000 800-1400 sq ft 

(currently under 

construction) for 

traffic 

management 

area. 1200-1700 

sq ft for signal 

shop area 

25 (under 

construction) 

Control room: one 

supervisor, one operator 

Signal shop: up to five 

maintenance staff 
25

2005 NATIONAL TRAFFIC SIGNAL REPORT CARD 

The National Traffic Signal Report Card was developed to answer the question: How well does 

the nation support its traffic signal systems? The report consolidated responses of 378 agencies 

across the United States on this subject. The overall score and grade related to maintenance 

practices as well as key findings from this report are summarized below. 

SUMMARY 

Maintenance practices had an overall national score of 67, or D+. The minimum level of 

operation and critical maintenance for traffic signal systems scored high across the surveyed 

agencies which were mainly attributed to ensuring public safety and limiting potential for 

increased liability. However, despite meeting minimum requirements, other components of 

maintenance programs such as planning, management, and execution contributed to the overall 

low score. 

The report defined key components of an excellent maintenance program. These components 

are: 

• Adequate maintenance staffing (or contract staffing) for traffic signals with a recommended 

staffing level of 30 to 40 intersections per technician. 

• Committing on-going funding to repair, replace, or upgrade signal controllers, detectors and 

other signal hardware. 

• Including as part of the project scope of work, timely replacement or repair to sensors or 

detectors that are destroyed or disabled by roadway maintenance or utility activities. 

• Providing and encouraging maintenance personnel to regularly attend technical training 

programs to familiarize themselves with the latest equipment and procedures associated with 

signal maintenance. 

• Regular assessment of the condition of traffic signal control equipment, including 

verification that detectors are working properly, traffic signal controller timings are entered 

correctly, verification that signal displays are operational, visual assessment of the alignment 

of traffic signal and pedestrian displays to make sure they are visible to motorists and 

pedestrians, and a semi-annual comprehensive assessment of all operating conditions. 

• Near real-time monitoring and emergency response, (7 days a week, 24 hours per day) for 

traffic signal system and intersection equipment using computer and communications 

facilities that provide reports to maintenance personnel within 5 minutes of detecting a 

failure. 

• Use of a maintenance management system database that tracks equipment failure histories, so 

as to avoid repeated purchase of unreliable equipment, and for scheduling proactive 

maintenance, rather than reacting to failures after they have occurred. 
26

• Policies or processes that define the time frame for responding to malfunctions and the 

agreed-upon criteria or prioritizing among multiple problems. 

In order to achieve an excellent maintenance program and in turn improve scores and grades in 

future report cards, several needs were identified. These needs include more adequate 

maintenance resources, increased staffing levels, improvement training, more frequent signal 

hardware upgrades and timing updates, and more training for traffic signal technicians. 

2007 NATIONAL TRAFFIC SIGNAL REPORT CARD 

In the update to the 2005 National Traffic Signal Report Card, the report showed an increase in 

both score and grade related to maintenance practices. The report consolidated responses of 417 

agencies across the United States and found the overall national score improved from 67 in 2005 

to 70 in 2007 with a corresponding improvement in grade from D+ to C-. The key findings from 

this report are summarized below. 

SUMMARY 

The 2007 report provided more specifics on the key components of an excellent maintenance 

program than provided in the 2005 report by adding the following: 

• Adequate policies and staffing (or contract staffing) to provide for timely response within 

one hour during normal business hours (within two hours outside of regular business hours) 

after a critical malfunction is reported. 

• Regular preventative maintenance and operational reviews, including a comprehensive semiannual maintenance review, quarterly operational reviews and annual conflict monitor 

testing, including formal documentation for some or all equipment. 

• Complete configuration management information (for example, schematics, interconnection 

information and software documentation) and inventories of all traffic signal control 

equipment. 

• Continuous malfunction monitoring notification of critical components that provide reports 

to maintenance personnel within five minutes of detecting a failure. 

• Maintaining operation for at least 90 percent of an agency’s detection system 

The report findings showed that two-thirds of surveyed agencies had policies or processes to 

provide a traffic signal technician at intersections with a reported critical malfunction in the 

times specified above. In addition, 69% of the agencies reported regular preventative 

maintenance and operational reviews. 
27

INTELLIGENT TRANSPORTATION SYSTEMS FOR TRAFFIC SIGNAL CONTROL 

(WWW.ITS.DOT.GOV) 

The US DOT website provides a summary of deployment benefits, costs, and lessons learned for 

a number of different transportation subject matters. One of these subject matters involves 

traffic signal control. The website was reviewed for information on traffic signal operations and 

maintenance. The findings of this review are summarized below. 

SUMMARY 

The website described several important benefits related to proper traffic signal operations and 

maintenance. Examples were given of several case studies that showed optimizing signal timing 

as a low-cost approach to reducing congestion that ranges from $2,500 to $3,100 per signal per 

update. Updating traffic signal control equipment, in conjunction with signal timing 

optimization, was also shown in the case studies to have a positive benefit on reducing delays. 

The website also provided several general rules of thumb for operations and maintenance of 

traffic signals. These include providing one traffic engineer for every 75 to 100 signals and one 

signal technician for every 40 to 50 signals and performing signal re-timings every 2-to-3 years 

at a minimum. 

The website also described the practices needed to properly deploy traffic signal systems for 

maximum benefit. These practices include devoting sustained resources to the system and the 

professionals who design, operate, and maintain them, making wise investments in current signal 

hardware, timing updates, and maintenance resources, and providing training for signal 

technicians and engineers to ensure proper operation and maintenance of traffic signals and to 

preserve the investment in the hardware and timing updates. 

TRAFFIC CONTROL SYSTEM OPERATIONS GUIDE (INSTALLATION, 

MANAGEMENT, AND MAINTENANCE) 

This guide was prepared in 2000 by ITE and includes summaries of covers topics on traffic 

signal systems that include operations, staffing, and maintenance. 

Operations 

For traffic signal operations, the guide describes the monitoring devices used to determine how 

well traffic signal systems are operating. Among these devices are TV surveillance, detectors, 

dynamic message signs, and traffic signal controllers. The guide therefore stresses the need for 

regular care of these devices. The day to day operation is described as a number of basic tasks 

and procedures that include maintaining checklists, ledgers or system parameter inputs and 

changes, running daily summary reports, system back-up of data, and incremental improvements. 

The guide also describes the use of modern computerized equipment to facilitate information 

processing. Over the years, the transition from paper filing systems to electronic filing systems 

has improved the speed and ability of operators to process information on traffic signal systems. 
28

In addition to improved information processing, the guide describes the benefits of automated 

data collection. A key benefit to this includes less costly data collection efforts as compared to 

manual labor. The guide also describes how ITS has improved information gathering for traffic 

signal systems such as by providing data streams of different equipment (e.g. on-board systems 

of buses, and commercial truck fleets) into traffic control systems and using this information to 

monitor the performance of a street. 

Data Synthesis, or Data fusion, is another key component of traffic signal system operations 

described by the guide. The data coming into the traffic control system must be in a form that is 

useful to the operator. It is also important for this data to be easily manageable and not require 

large amounts of time to reduce. Finally, the guide describes the importance data information 

dissemination. The information gathered through traffic signal operations is useful to a wide 

audience and is therefore shared with groups such as service representatives, road users, and 

transit patrons. 

Outside of information gathering, data synthesis, and dissemination, the guide stresses the need 

for quality documentation of operator functions, maintenance procedures, and operating 

software. 

Staffing 

The guide also provides summaries of staffing levels from three sources: Hampton, VA, Menlo 

Park, CA, and NCHRP Synthesis 245. The City of Hampton surveyed 23 similar sized cities 

(approximate pop. 141,000) which found an average of one traffic engineer per 76 traffic signals 

and one traffic signal technician per 47.1 traffic signals. The NCHRP survey concluded that a 

traffic signal technician could maintain between 38 and 43 traffic signals. When evaluating 

staffing needs, the City of Menlo Park recommends one traffic signal engineer for every 100 

traffic signals and one traffic signal technician for every 50 traffic signals. 

From this information, the guide concludes that one single maintenance person can maintain 40-

50 traffic signals or other field devices. 

Maintenance 

Common provisions for maintenance were also covered in this guide. The first provision 

covered in the guide was on the personnel required for traffic signal systems. This included a 

definition of five general personnel classifications including traffic signal mechanic, supervising 

traffic signal mechanic, traffic signal technician, traffic signal engineer, and traffic engineer. 

The guide also included basic guidelines for qualifications, training, and experience for each 

personnel classification. This guidance is as follows: 
29

Personnel Experience Requirements 

Title Responsibilities Experience Requirements 

Engineer Management, operations, and 

design; system checks; 

modifications to timing; 

supervision of daily activities 

B.S. in Civil or Electrical 

Engineering (M.S. desirable), 

Engineer-In-Training (E.I.T.) or 

P.E., 1-3 years experience, IMSA 

certification 

Supervisor Supervise crews; schedule work 

activities; oversee maintenance, 

operations, and construction; 

issue work orders 

IMSA certification, FCC license, 

CDL, journeyman skills level 

Technician Responsive and preventative 

maintenance, troubleshooting, 

equipment repair and installation 

IMSA certification, CDL, 

electronics and electrical training 

or Associates degree 

Mechanic Troubleshooting, perform repairs 

and maintenance, installation of 

equipment 

Controller and conflict monitor 

training, IMSA certification, 

master skills level 

The guide also covers provision of various maintenance equipment including maintenance 

vehicles, test equipment and tools, replacement parts and supplies. For each of these categories, 

the guide offers an itemized list of equipment, estimated quantities and prices for average 

conditions. The guide also provides guidance on the preferred location of repair shops for traffic 

signal equipment as well as considerations for layout, size, organization, outfitting, staffing, and 

budget for these types of shops. 

The importance of good maintenance records was also stressed within the guide. The records 

needed for effective maintenance are described as falling into maintenance service records, 

signal timing charts, and maintenance manuals and as-built plans. The maintenance service 

records include the two main types of maintenance performed by traffic signal departments 

which are preventive and responsive. Another type of maintenance record required of traffic 

signal departments described by the guide is design modifications. This includes the 

documentation of changes to the approved design and operation of existing system installation to 

corridor recurring problems, accommodate changes in prevailing conditions, or updates since 

installation. 

The guide also provided information on estimated maintenance requirements associated with five 

common traffic signal configurations for example purposes. From these examples, the guide 

deduced that the “average” intersection requires a total of 60 hours of annual maintenance of 

which 70% is devoted to preventive maintenance, 25% to responsive maintenance, and 5% to 

design modification maintenance. The guide also concludes that signal mechanics have 1,627 

estimated annual work hours to perform maintenance which translates to the capability of 

maintaining 17-27 intersections per year. 
30

2.2 FIELD SURVEY 

2.2.1 Overview 

This section provides a summary of the survey responses received from various agencies on the 

FHWA sponsored Traffic Signal Operations and Maintenance Staffing and Resource 

Requirements questionnaire. The purpose of this questionnaire was to seek input on current 

traffic signal operations and maintenance practices and to use this information in the 

development of guidelines developed in subsequent project tasks. 

The 2005 and 2007 National Traffic Signal Report Cards (NTSRC) highlight a number of better 

practices that are believed to contribute to effective traffic signal management, operations and 

maintenance processes. Table 2.2 summarizes recommendations from the report card gathered 

from a number of sources, for staffing and resource needs for traffic signal operations and 

maintenance. A survey was also conducted in conjunction with the development of this report 

and those survey results are presented in the following table as well. 

Table 2.2 

Comparison of Key Results from the National Traffic Signal Report Card

Criteria NTSRC Recommendation Project Survey Results 

Traffic Signal O&M 

Maintenance 

Staffing 

30 to 40 signals per technician 

38 to 61 signals per technician (this 

includes the maintenance of ancillary 

devices as well such as CCTV, CMS, 

etc) 

Signal Monitoring 

Near real-time 24/7 monitoring of 

signals to provide reports to 

maintenance personnel within 5 

minutes of automatic failure report. 

24/7 monitoring of traffic systems not the 

rule. Most isolated intersections have no 

automated failure reporting capability 

Critical Malfunction 

Response Time 

Should not exceed one hour during 

business hours and 2 hours at other 

times. 

Reporting agencies averaged 1.4 hours 

during business hours and 1.9 hours at 

other times. 

Detection System 

Maintenance 

Maintaining operation for at least 

90% of an agency’s detection 

system. 

This goal appears to have been 

achieved for local actuation detectors but 

not for system detectors. 

The section describes the survey distribution process and the feedback received from 

respondents. The report then compiles survey responses by the following subject areas: 

• Classification of Signal System Characteristics 

• Redundancy Characteristics of System 

• Traffic Detection 

• Timing plan characteristics 
31

• Operations characteristics 

• Maintenance practices 

• Staff size and qualifications 

2.2.2 Definition of Traffic Signal System Management, Operation and 

Maintenance 

Transportation system management and operations is described by the Technical Corrections Act 

(6) as follows: 

(A)IN GENERAL- The term ‘transportation systems management and operations’ means 

an integrated program to optimize the performance of existing infrastructure through 

the implementation of multimodal and intermodal, cross-jurisdictional systems, 

services, and projects designed to preserve capacity and improve security, safety, and 

reliability of the transportation system. 

(B) INCLUSIONS- The term ‘transportation systems management and operations’ 

includes— 

‘(i) regional operations collaboration and coordination activities between 

transportation and public safety agencies; and 

‘(ii) improvements to the transportation system, such as traffic detection and 

surveillance, arterial management, freeway management, demand management, work 

zone management, emergency management, electronic toll collection, automated 

enforcement, traffic incident management, roadway weather management, traveler 

information services, commercial vehicle operations, traffic control, freight 

management, and coordination of highway, rail, transit, bicycle, and pedestrian 

operations. 

Concurrently with the survey conducted under this task, a related survey was conducted by the 

Puget Sound Regional Council (7). Results of the Puget Sound survey that are relevant to survey 

topics under this project are also included. 

2.2.3 Survey Distribution and Respondents 

The questionnaire that was distributed is included in the Appendix A of this memo. While the 

Traffic Signal Report Card survey provided a broad overview of operations practices and 

established a basis for comparatively evaluating agency performance, the survey was intended to 

provide an in-depth view of the practices of a limited number of agencies. It was desired to 

obtain responses from 10 agencies that could serve to assist in establishing the basis for superior 

practices, however it was only possible to obtain seven in-depth responses. The initial 

distribution list included a total of 34 agencies of different sizes, type, and locations. The survey 

was first distributed in July 2008 via email to each of the agencies. This first distribution was 

then followed up by subsequent reminder emails and telephone calls. Of the 34 potential 

respondents, a total of seven agencies provided feedback. The responding agencies and their 
32

signal system network characteristics are shown below in Table 2.3. Note that the agency names 

are not presented to protect the anonymity of the respondents the type of agency, state and 

population of the jurisdiction are germane to this discussion and are provided to characterize 

each survey response. Appendix B provides a tabulation of the survey responses. 

Table 2.3 

Survey Respondents and Traffic Network Characteristics 

Number of Signals in 

Each Network Type Agency Agency 

Type 

Service 

Area 

Population 

(Approx.) 

State Total 

Signals Grid Arterial Isolated 

Approx. % 

Growth in 

Signals/Year

A Urban 

county 600,000 Florida 780 390 314 76 6% 

B City 800,000 Florida 1,001 135 415 451 Not Available

C Urban 

county 800,000 New York 622 85 362 175 <1% 

D 

City 

near 

major 

city 

40,000 Georgia 115 0 25 90 4% 

E City 350,000 Californi

a 

300 180 80 40 1% 

F County 900,000 Maryland 800 200 525 75 1% 

G DOT N/A Georgia 2800 350 1050 1400 3% 

Table 2.4 shows a partial set of responses regarding the operational characteristics of these 

traffic signal system networks. Those agencies providing responses on this indicated that traffic 

volumes were growing in the range of 1% to 5% and the level of saturation experienced. 

Table 2.4 

Traffic Network Operations 

Approx. % of signals operating under saturated conditions* 

Agency 

Peak hour At least one hour outside of peak hour 

Total Signals 

A 30% 30% 780 

C 3.2% 0.8% 622 

D 15% 5% 115 

E 60% 50% 300 

F 40% 50% 800 

G 15% 2% 2800 

*Examples of saturated conditions include cycle failure (failure of a motorist to be serviced by the green phase 

subsequent to his arrival), long persistent queues and volume to capacity ratios that closely approach or appear 

to exceed 100%.
33

Traffic delays increase modestly until a volume to capacity ratio of approximately 0.9 is reached, 

at which point delay increases exponentially. Thus the capability of an agency’s staff to identify 

saturation or near-saturation conditions (by on street observation, CCTV observations and data 

mining) and to remedy the situation strongly influences the level of delay that motorists will 

experience. 

Additionally, it was found that these agencies operate traffic management centers. The hours of 

operation for these centers varied from nine (9) hours per day to 17 hours per day. Three of the 

agencies reported co-location in their traffic management centers with other operators such as 

Department of Transportations, State Police Departments, Transit, 911, and Emergency 

Operations. 

2.2.4 Classification of Signal System Characteristics 

The respondents were asked to provide an inventory of the field devices and operational 

strategies used with their traffic signal system. This included traffic signal controllers, traffic 

detectors, ancillary devices, and communication systems. 

Traffic Signal Controllers

The type and age of the equipment has a bearing on some of the challenges that a municipal 

traffic engineer faces, the premise being that the greater the number of different types of 

equipment present in a signal system, the more difficult it is to operate and maintain. This 

additional difficulty results from the additional spares inventories required as well as the 

additional training and configuration management required. Similarly, it is likely that an agency 

that uses older technology will have differences in hardware and software that may result in 

different operations, making troubleshooting more difficult for the technician in the field. The 

traffic signal controller classifications used by the respondents are summarized in Table 2.5. 

Table 2.5 

Traffic Signal Controller Inventory 

Standard Classification Controller Age 

Agency 

Type 170 ATC/ 

2070 

NEMA 

TS1 

NEMA 

TS2 <5 Years Between 5 & 

10 Years 

> 10 

Years 

A 0% 0% 40% 60% 25% 67% 8% 

B 6% 17% 69% 8% 27% 13% 60% 

C 0% 0% 35% 65% 10% 55% 35% 

D 0% 97% 0% 3% 100% 0% 0% 

E 0% 60% 40% 0% 27% 40% 33% 

F 0% 0% 0% 100% 0% 75% 25% 

G 0% 100% 0% 0% 36% 64% 0% 
34

The agencies operate all of their traffic signal controllers in time of day mode with the exception 

of Agency A which operates approximately 12% of their network using traffic responsive mode. 

The number of timing plans used varied from three to seven plans per weekday and from two to 

four plans per weekend day or special event. The agencies reported using other non-periodic 

timing plans as well such as during emergency evacuation plans, detour plans, heavy volume 

plans. Agency A also reported the operation of peak and off-peak seasonal plans that take into 

account fluctuations in traffic volumes at different times of the year. The Puget Sound Survey 

reported that traffic responsive operation was used by 15% of the agencies. 

Four of the respondents reported retiming at three year intervals or less and one respondent 

reported retiming at five to seven year intervals. Two respondents retime on an as needed basis. 

One of these agencies uses aircraft and cameras to assist in determining the need for retiming. 

Traffic Detection 

The respondents also provided a breakdown on the traffic detection strategies employed at their 

intersections. This breakdown is shown in Table 2.6. 

Table 2.6 

Traffic Detection Configuration 

Fully Actuated Configuration Semi-Actuated 

Configuration 

Agency Advanced & limit line 

detection on main street, 

limit line detection on side 

street approaches 

Advanced detection 

on main street & 

limit line on side 

street 

No detection on 

main street, limit line 

detection on side 

street. 

No 

Detection 

A 1% 98% 1% 0% 

B 75% 12% 0% 13% 

D 100% 0% 0% 0% 

E 30% 70% 0% 0% 

F 5% 5% 75% 15% 

G 2% 93% 5% 0% 

Five of the agencies surveyed also provided estimates on the percentage of operable local 

actuation detectors. These agencies reported very high percentages (90% or greater). The 

agencies periodically check the operability of their traffic detectors through preventative 

maintenance programs, routine monitoring of central system software, and when complaints are 

made. 

The survey results also showed that only one of the agencies is analyzing detector data on a 

regular basis. This data is being used to determine spot traffic flow conditions, real-time 

volumes, peak hours, and yearly daily traffic volume trends. 
35

The Puget Sound survey reported that 28% of the agencies did not send real-time traffic 

information to a central computer or master controller. 

Ancillary Devices

The ancillary devices also maintained by the responding agencies are provided in Table 2.7. 

These devices include emergency preemption/transit signal priority equipment, Closed Circuit 

TV (CCTV) cameras, Changeable Message Signs (CMS), and Uninterrupted Power Supplies 

(UPS). 

Of the six agencies that reported using CCTV cameras operated by that agency, four reported on 

the use of these cameras to support on-line adjustment of timing plans, planning for signal 

timing/phasing, and incident management. One agency reported using CCTV monitoring to 

support on-line adjustment of timing plans and incident management and another agency uses 

CCTV only for incident management. 

Table 2.7 

Ancillary Devices (Number of Units) 

Agency Preemption/ 

Priority 

CCTV CMS UPS 

A 20 3 0 18 

B 50 0 0 4 

C 351 75 2 0 

D 60 9 0 9 

E 1 60 13 0 

F 25 180 0 0 (near term plans 

includes installation of 

250 UPS units) 

G 70 2 0 100 

The Puget Sound survey determined that 79% of the agencies used CCTV to monitor traffic and 

that 53% of these agencies used the cameras for incident management as well. 23% of the 

agencies used CMS. 

Communication Systems 

The survey sought information on the various types of communication systems being used by 

agencies with their traffic signal systems. These communication systems provide a data transfer 

link between traffic signals and in some cases provide a means for communicating remotely to a 

traffic management center. Table 2.8 provides a summary of the survey results showing the 

number of signals within each communication system type. 
36

Table 2.8 

Communication Systems (Approximate number of signals) 

Agency Total 

Signals 

None 

(Isolated) 

7-wire 

Cable 

Twisted 

Wire Pair 

Fiber Optics Coaxial 

Cable 

Wireles

s 

A 393 76 0 292 5 0 20 

B 1000 450 0 30 193 directly; 

319 remotely 

0 8 

C 620 175 10 20 100 305 10 

D 104 34 0 0 70 0 0 

E 250 60 0 170 7 0 13 

F 800 0 0 800 0 0 0 

G 2800 1950-2250 0 200 300-500 0 50 

For the isolated traffic signals, the survey respondents indicated that only one agency uses 

automatic failure reporting at some locations. The respondents also indicated that portions of 

their traffic signal system operate with remote monitoring capabilities either as a closed loop 

system or through central control. The information provided on this capability is presented in 

Table 2.9. 

Table 2.9 

Number of Traffic Signals with Remote Monitoring Capabilities 

 

Agency Closed Loop Central Control 

A 0 314 

B 550 0 

C 47 405 

D 80 0 

G 750 (additional 150 isolated 

intersections report failures)

0 

The number of traffic signals reported in the table above includes coordinated systems as well as 

isolated locations. The redundancy characteristics of the traffic signal systems were also reported 

on by the survey respondents. This included redundancy of central controls and both backbone 

and distribution communication systems. The redundant characteristics of the central controls 

included software/server based systems that can be transferred to backup systems as needed, 

spare data storage and communication servers, and regular off-site backup of system data. 

The agencies reported accomplishing redundancy with their backbone and distribution 

communication systems by providing alternate paths in the case of communication breaks. 
37

2.2.5 Staff Levels and Qualifications 

The number of staff responsible for traffic signal operations and maintenance along with their 

required qualifications were also provided by the agencies participating in this survey. This 

information is presented in Table 2.10 and includes the number of personnel in each of the 

identified positions. Where data was available, the qualifications, training, and experience level 

is also provided. 

Analysis of the Puget Sound survey data for agencies operating in excess of 150 signals found 

that the number of maintenance technicians ranged from 18.4 to 78.9 per thousand signals. The 

large differences may be attributable to varying definitions of labor categories and maintenance 

tasks. 

The data in Table 2.10 was analyzed according to the following Knowledge, skills and abilities 

categories described in Section 1.3.3.3

 

Table 2.10 

Staff Levels and Qualifications 

Number of full time equivalent positions2

Agency Total 

Signals 

Management

/ Traffic 

Engineer/ 

ITS Engineer 

Traffic Signal 

Analyst/ TMC 

Operator

Traffic Signal 

Maintenance 

Tech./ 

Electronic 

Specialist

Qualifications, training, 

experience level 

A1 393 3.5 4.5 10 

Require minimum of three 

years electrical experience, 

IMSA II, and IMOT 

certification for Traffic Signal 

Maintenance Technicians 

B 1000 2 1 16 IMSA certification for 

technicians 

D 104 2 1 6 

Require Management to have 

P.E + 10 years of experience, 

Traffic Signal Engineer to 

have P.E., PTOE + 10 years 

of experience, Traffic Signal 

Analyst/Tech. to have 10 

years of experience 

E 250 5 9 5 No certifications required for 

engineers or technicians 

                                                     

3

 Categories correspond to the those defined in Row, S., Tarnoff, P.J. Traffic Signal Training Assessment Summary 

Report 7, Federal Highway Administration, July 2005. 
38

Number of full time equivalent positions2

Agency Total 

Signals 

Management

/ Traffic 

Engineer/ 

ITS Engineer 

Traffic Signal 

Analyst/ TMC 

Operator

Traffic Signal 

Maintenance 

Tech./ 

Electronic 

Specialist

Qualifications, training, 

experience level 

F 800 5 7 14 

No certifications required for 

engineers or technicians 

G 2800 16 0 46 

No certifications required for 

engineers or technicians 

1Agency A also reported a public relations position that serves traffic signal operations and maintenance which is not

reflected in the table.  

2 The survey results found that agencies use a variety of job descriptions to characterize the typical functions of these

positions.  Therefore, the table generalizes these positions into the three categories shown.

The survey also provided information on the average tenures of both engineering and 

maintenance staff. The average tenures of engineering staff was found to be between five (5) 

and twelve (12) years while the average tenure of maintenance staff was found to be between 

five (5) and twenty (20) years. 

Table 2.11 shows a comparison of these results for the medium and larger signal systems. The 

analysis is approximate in that the categories in Table 2.9 do not directly correspond to the 

questionnaire categories. 

Table 2.11 

Comparative Staffing by Agencies 

Number of signals per staff 

Agency Number of Signals Traffic Engineer Maintenance 

A 383 85 35 

B 1000 500 63 

E 250 33 33 

F 800 160 57 

G 2800 175 61 

The widespread variations in the engineering areas are at least partly attributable to the 

definitions of the positions by different agencies. Analysis of the Puget Sound data indicated 

that for agencies operating in excess of 150 signals, the number of maintenance technicians 

ranged from 18.4 to 78.9 per thousand signals. These large differences are most likely 

attributable to differences in labor categorizations, combined task assignments and variations in 

the definitions of maintenance tasks. 

2.2.6 Maintenance Practices 

The survey included a number of questions regarding maintenance of traffic signal systems. The 

feedback provided insights on the allowable and actual practices used by each agency when 
39

responding to maintenance requests. Feedback was also provided on the distance between traffic 

signals and maintenance facilities. The information provided is summarized in Table 2.12 and 

Table 2.13. 

Table 2.12 

Proximity of Traffic Signals to Maintenance Facilities 

Agency 5 miles or less Between 5 and 

10 miles Greater than 10 miles 

A 76 57 257 

C 481 125 20 

D 100 15 0 

E 170 120 10 

F 200 500 100 

G 175 250 2375 

Table 2.13 

Maintenance Response Times 

Signal Failure 

Repairs during 

Business Hours 

Signal Failure 

Repairs during Nonbusiness Hours 

Ancillary Equipment 

Failure Repairs Agency 

Allowable Actual Allowable Actual Allowable Actual 

Communication 

System Failure 

Repairs during 

Non-business 

Hours 

A 2 hours 1 hour 4 hours 2 hours 48 hours 24 hours 48 hours 

E 1 hour 1-2 

hours 2 hours 1-3 hours 2 weeks 

From 2 

hours to 3 

days 

2-3 days 

F 0.5 hours 0.5 hours 

or less 0.5-1 hour 

1.5 

hours or 

less 

Dependen

t upon 

device 

Dependent 

upon 

device 

30 minutes 

G 2 hours 2 hours 2 hours 2 hours Typically 

one week 

Typically 

one week 

Typically one 

week 

In addition, several of the responding agencies reported on the annual number of traffic signal 

controller failures. The information provided showed a range of failures from less than 1% per 

year to more than 10% per year. 

2.2.7 General Observations 

The following additional observations were made based on a review of the survey responses. 
40

Signal Operations

• There is a suspected relationship between the degree of traffic congestion in cities 

and counties and their staffing levels. 

• Isolated signals generally do not have the capability to automatically report failures. 

• There is some use of changeable message signs (CMS) and increasing use of 

CCTV. Where available, CCTV is used for on-line adjustment of signal timing, 

planning for signal timing and phasing and incident management. 

• Although most signals have some form of detection, and in many cases the 

detector data is available at the TMC, this data is generally not mined or 

reviewed for intersection performance, or reviewed to determine the need for 

signal timing updates. 

• PE and/or PTOE certification is generally not required for signal system 

engineers (the survey sample may be too small to form a general conclusion.) 

Maintenance

• Field maintenance of controllers is generally accomplished quickly (0.5-2 hours 

during business hours and 1-3 hours during non-business hours). 

• Maintenance of detectors and other devices may not be performed for prolonged 

periods. 

• On the average, controllers are from five to ten years old. 

• Certification of maintenance technicians is required by some agencies but not by 

others. There is no consistent pattern. 

• There is a wide variation in controller failure rate. Determining the causality of this 

variation might yield productive modifications to maintenance practices. 

Management

• There is little general use of measures of effectiveness measures or performance 

reports. 

• Future planning cycles generally range from three to five years. 

• Provisions for feedback from the public vary considerably in ease of accessibility 

among agencies. 

• Mission statements, concepts of operations and operations procedures are generally 

not provided by agencies. 

• Training provisions are generally inadequate and not systematized.
41

• Funding inadequacy appears to play an important role in management and operational 

deficiencies. 

2.3 OPERATIONS AND MAINTENANCE STAFFING AND RESOURCES 

2.3.1 Introduction 

A traffic signal system conforming to Objective Oriented Operation (OOO) provides 

performance, reliability and functional requirements necessary to achieve a high quality of 

operation at a reasonable cost. This section identifies the resources that are most likely to be 

needed to achieve OOO. The resources include sufficiently qualified personnel and the staffing 

levels required to implement the functions. An estimate is provided for signal retiming costs. 

While an agency’s ability to achieve operational objectives is related to budget and number of 

staff management approach, staff commitment, dedication and training are intangible elements 

that dictate how effectively an agency can operate and maintain a traffic signal system. The 

level of maintenance and operations is not only affected by the agency’s perception of its 

importance but also by the public’s perception. Under budgetary constraints, cutting programs 

for training and professional development provides short-term relief but undermines the longterm viability of the system’s operation and maintenance. 

2.3.2 Resource Requirements for Traffic Engineering 

The person responsible for traffic system engineering (planning, system operations, equipment 

selection, signal timing) should have professional engineering (PE) registration and should 

preferably have professional traffic operations engineer (PTOE) certification. Other engineering 

personnel should either have these qualifications or be in the process of actively pursuing their 

acquisition. 

Staffing Level for Traffic Engineering Personnel

Table 2.14 provides a summary of the engineering staffing levels developed by various 

references: 

Table 2.14 

Number of Signals per Traffic Engineer 

Reference Number of Signals per Traffic Engineer 

Traffic Control System 

Operations: Installation, 

Management and 

Maintenance (12) 

75-100 

Survey performed under this 

project 

Average: 185 
42

Reference Number of Signals per Traffic Engineer 

Survey performed under 

Puget Sound Regional ITS 

Implementation Plan (7) 

Average: 67. For agencies with over 150 signals the average s 

93. 

Median: 62. For agencies with over 150 signals the median 81. 

62% of the responding agencies felt that their staff size was 

inadequate. 

Survey responses show wide variations in comparative staffing levels. To some extent, this 

reflects the phraseology used for the survey questions and varying interpretations by the 

respondents. Based on the table above, it appears that a staffing level of 75-100 signals per 

engineer for agencies that operate a minimum of 150 signals will be appropriate to support OOO. 

Smaller agencies will likely require fewer signals per engineer because economies of scale are 

difficult to realize. The engineering staff to support these functions should, as a minimum: 

• Provide for the collection and analysis of traffic and accident data to determine the 

need for retiming, rephasing, and pedestrian treatment on a 30 to 36 month basis. 

Retiming should follow in a timely manner. 

• Analyze traffic system reliability data annually to determine those locations where 

unusual equipment failure rates result in excessive delay and safety problems. Steps 

to remedy these conditions should be planned and implemented. 

• Collect, analyze and report data yielding measures of effectiveness, in order to assess 

the quality of the traffic signal service being provided. Develop strategies to remedy 

deficiencies including traffic system and geometric upgrades.

2.3.3 Cost of Signal Retiming 

The cost of signal retiming generally lies within the $2500-$3500 per intersection range (8,9). 

Table 2.15 provides a typical consultant’s estimate of the time required per intersection to 

accomplish key activities associated with signal timing. 

Table 2.15 

Person Hours for Key Signal Timing Activities (10) 

Task Person Hours per Intersection 

Project management 0.8 

Weekday turning movement counts 19.8 

Saturday turning movement counts 4.6 

Field intersection inventory 1.5 

Qualitative assessment 1.5 

Signal timing analysis 7.5 
43

Task Person Hours per Intersection 

Fine tuning 6.0 

Final delivery 1.3 

2.3.4. Resource Requirements for Maintenance Personnel 

Qualifications

Personnel in agencies that perform their own maintenance should conform to the following as a 

minimum (agencies that contract maintenance services should require contractors with similar 

qualifications): 

The technician in charge of signal maintenance should have the following qualifications: 

• Combination of training, education and experience for a total minimum of five years. 

• Certification to IMSA Traffic Signal Level II. 

• Additional training beyond IMSA Traffic Signal Level II. 

The number of subordinate positions depends on the number of signals for which the agency is 

responsible. Qualifications for two subordinate levels are described below: 

Technician 2 - Minimum of 2 years as Technician 1 plus: certification to IMSA Traffic Signal 

Level II. 

Technician 1- 

• High school (minimum). 

• Knowledge of electrical standards, codes, practices and repair techniques. 

• Certification to IMSA Traffic Signal Level I within one year of employment 

In addition, all technician levels must be able to work for long periods in inclement weather and 

may be required to lift heavy objects and work from bucket trucks. 

Staffing Levels for Maintenance Personnel

Table 2.16 provides a summary of the maintenance technician staffing levels developed by 

various references: 

Table 2.16 

Signals per Technician

 Reference Signals per Technician 

2005 Traffic Signal Report Card 

recommendation 

30-40 
44

 Reference Signals per Technician 

Traffic Control System 

Operations: Installation, 

Management and Maintenance 

(12) 

40-50 

Survey performed under this 

project 

Average: 51 

Survey performed under Puget 

Sound Regional ITS 

Implementation Plan (7) 

Average: 24 for all agencies, 29 for agencies with over 150 

signals. 

Median: 21 for all agencies, 30 for agencies with over 150 

signals 

Variations in the data are significant. In particular, data for the smaller agencies tends to vary to 

a greater extent and to skew the averages. Based on the table above, it appears that a staffing 

level of 30-40 signals per technician for agencies that operate a minimum of 150 signals will be 

appropriate to support the Constrained Ideal Traffic System. Smaller agencies will likely require 

fewer signals per technician because economies of scale are difficult to realize. 

2.4 Evaluation of Agencies Relative to CITS Criteria 

This section relates agency practices to OOO criteria. Section 2.4.1 describes this relationship 

for the agencies interviewed under this project while Section 2.4.2 provides a general over view 

of current practices relative to these criteria. 

2.4.1 Evaluation of Agencies Surveyed 

 The interview responses were evaluated using the OOO criteria described in the preceding 

sections. A scale of 1-5 (5 being the best) was used to rate the interview responses against 

certain of these criteria. Table 2.17 describes the specific criteria used in the evaluation. A score 

of 5 represents achievement of OOO criteria. The results of this analysis are shown in Table 

2.18. That table, and the survey responses themselves, were used to develop the evaluations 

described below. 

Table 2.17 

Survey Evaluation Criteria

Management 

1. Planning – Availability of planning procedures and documentation (mission statement, annual reviews, 

concept of operations, regional ITS architecture conformance, strategic plan) provides a rating of 5. 

2. Data mining – Collection and analysis of traffic data on a 30-36 month basis to determine timing plan 

needs and evaluate system performance provides a rating of 5. 
45

Operations 

1. Monitoring at TOC – For the larger agencies, 24/7 monitoring is preferred (score of 5) while monitoring 

during weekday peak periods and at other critical times is awarded a score of 4. 

2. Personnel qualifications – A score of 5 is awarded if the traffic engineering staff and timing plan 

preparation is supervised by a PE or PTOE. 

3. Use of CCTV – The use of CCTV (and in some cases aircraft) is an estimation of the anecdotal 

capability to identify traffic signal timing problems. A score of 5 represents CCTV coverage of a minimum 

of one-third of the intersections 

4. Number of timing plans – This is a measure of the agency’s likely performance as well as the agency’s 

intent to span the coverage of needs. The availability of 6 or more timing plans is awarded a score of 5. 

5. Frequency of timing plan update – A score of 5 represents updates at two year intervals or less, 4 

represents 2 to 3 year intervals and 3 represents 3-5 year intervals. Lower scores are awarded for longer 

periods. 

Maintenance 

1. Time to obtain indication of critical failure – Automatic failure reporting is necessary to achieve 

acceptable performance. To receive a score of 5, for systems in excess of 400 intersections, 70% of 

these failures should be detected automatically. For smaller agencies, 30% of the failures should be 

detected automatically. Lower scores are awarded for less detection capability. 

2. Time to respond after receiving indication of critical failure – To receive a score of 5, a response within 

one hour during business hours and within two hours during non-business hours is required. Lower 

scores are awarded for longer response periods. 

3. Maintenance technician qualifications and training – A score of 5 is awarded if IMSA or equivalent 

certification is required and training resources are available. Lower scores are awarded for lesser levels 

of certification and training provisions. 
46

Table 2.18 

Evaluation of Agencies Relative to Constrained Ideal Traffic System 
47

2.4.2 Overview of Current Practices 

Management, Operations And Signal Timing 

Within the limitations of their resources, agencies generally strive to provide operations and 

maintenance services to the extent possible. Most of the agencies interviewed, however do not 

manage in a top down fashion, i.e. they do not generally systematically collect and analyze data 

and make systematic reviews of traffic system performance using established measures have 

procedures. 

Among the agencies interviewed, the number of timing plans employed and the frequency of 

timing plan updates, while somewhat deficient, probably do not constitute the most serious 

deficiency. The agencies do not generally analyze detector data collected by the traffic systems 

for the purpose of determining the number of timing plans needed and the time periods for which 

they are required. These values appear to be established by anecdotal or judgmental means (that 

appear to be influenced by the increasing use of CCTV and, in one case, by surveillance 

aircraft.) This statement is supported by a the following similar observation in Tarnoff and 

Ordonez (1) “...more than 98% of the jurisdictions rely on engineering judgment to determine 

the best times of day for new plans. It must be emphasized that in many cases this approach is 

highly appropriate. However it is possible that within the 109 agencies that responded to this 

question, there are situations where a more quantitative approach should be used.” 

While the problem may, in part, be caused by the lack of qualifications on the part of the 

engineering staff, the deficiency principally appears to stem from: 

• The lack of a management plan for the review and evaluation of detector data and the 

determination of deficiencies, need for new timing plans, number of timing plans and 

for the time periods for which the plans should be employed. 

• The lack of guidance material and analysis tools for developing these requirements. 

Maintenance Practices

While the response to field failures when the agency is notified of a failure is generally 

satisfactory, the following deficiencies are apparent among the responding agencies: 

• No capability is generally provided for control equipment at isolated intersections to 

report failures. Thus agencies whose operations include a significant percentage of 

isolated intersections are not able to detect these failures in a timely way. 

• Many agencies substandard personnel qualification criteria and training programs. 
48

2.4.3 Relationship of Agency Practices to Objective Oriented 

Operation (OOO) 

Table 2.19 compares characteristics of currently operating traffic systems with OOO criteria. 

The first column of Table 5.1 summarizes the general features that may be used to characterize a 

traffic control system. These are described in more detail in Section 3. The remaining columns 

classify how systems of different quality generally address these characteristics. Column A 

summarizes the CITS approach. It is generally characterized by strong management planning 

and control that in turn leads to the use of systematic processes for signal timing operation, and 

management of the entire signal system operation. It generally corresponds to a NTOC Report 

Card rating of A. Column B describes systems that range in performance from below CITS 

requirements to just above minimally acceptable operation. These systems generally correspond 

to Report Card Ratings of B or C. Column C describes systems that do not generally provide 

acceptable responsiveness to the transportation needs of the community and correspond to 

Report Card ratings of D or F. 

TABLE 2.19 

COMPARATIVE KEY CHARACTERISITICS OF TRAFFIC SYSTEMS

Characteristic A. Constrained Ideal Traffic 

System (CITS) 

B. Generally Above 

Average Systems 

that do not Meet 

CITS Criteria 

C. Traffic Systems 

with Below 

Average 

Performance 

Management 

- Supervision by PE 

and/or PTOE Always. Usually. Usually. 

- Planning reviews and 

documentation 

(mission statement, 

management plan, 

concept of operations, 

operating procedures) 

Reviews and updates of items 

needed on annual basis. 

All items may not be 

available. Reviews 

and updates nonperiodically. 

Most items not 

available. 

- Performance 

monitoring and annual 

review to determine 

deficiencies and needs 

Comprehensive and 

systematic monitoring 

program and review 

processes. 

Monitoring may be 

limited to key areas or 

routes and may not be 

performed periodically. 

Little systematic 

attention, usually 

reactive to crises. 

- Communication path 

to public, surveys 

Well publicized and easy to 

use, proactive outreach. 

Responds to public 

contact but does not 

proactively seek. 

Minimal attention. 

- Conformance with 

Regional ITS 

Architecture and 

interaction with other 

stakeholders Proactive participation Responds to requests 

generated by others Minimal participation 
49

Characteristic A. Constrained Ideal Traffic 

System (CITS) 

B. Generally Above 

Average Systems 

that do not Meet 

CITS Criteria 

C. Traffic Systems 

with Below 

Average 

Performance 

Timing Plan Design 

- Signal timing reviews 

and updates 

30 to 36 month updates using 

a documented methodology. 

May be reviewed more 

frequently if automatically 

collected data is available and 

processed. 

3 to 5 year updates. 

Greater than 5 

years, often in 

response to crises or 

other stakeholder 

requirements. 

- Number of timing 

plans 

Methodology used to 

determine number of daily 

plans needed. Sufficient 

number of plans provided to 

support daily needs, special 

events, weekends, diversion 

plans, transit needs, Spillback 

and saturation given special 

attention. 

Number and duration 

of plans determined by 

traffic engineer’s 

experience. 

Relatively few plans 

available. 

Operations 

- Real time traffic 

condition monitoring 

Adequate surveillance 

capability available for 

development of measures. 

CCTV at key intersections. 

Surveillance capability 

only able to provide 

partial measures. 

Little CCTV. 

Little operative 

surveillance 

capability except for 

detectors used for 

local actuation. No 

CCTV. 

- Equipment failure 

monitoring 

Failure monitoring available 

and operative for all signals 

featuring traffic progressions. 

Failure monitoring available 

and operative for most 

isolated signals. 

Failure monitoring 

generally available and 

operative for signals 

featuring traffic 

progressions, but not 

for isolated signals. 

Failure monitoring 

sometimes available 

and operative for 

signals featuring 

traffic progressions, 

but not for isolated 

signals. 

- Plan for upgrades 

Periodic review of data to 

determine need for geometric 

and signal system upgrades 

with emphasis on bottleneck 

and saturation relief. 

Reviews usually nonperiodic or as required 

by other stakeholders. 

As required by other 

stakeholders. 

- Traffic management 

center operational 

periods 

Weekday peak periods and at 

other times as warranted by 

traffic conditions. For 

moderate and major 

metropolitan areas this usually 

includes all day for weekdays 

except for evening and early 

morning periods. 

Weekdays but certain 

key periods may not 

be covered. Varies for 

other key periods. 

Traffic systems 

usually monitored 

periodically but not 

continually. 

- Changes in functional 

requirements (e.g. 

preemption, transit 

priority, etc.) 

Periodic review and 

implementation. 

Non-periodic review or 

response to other 

stakeholders. 

Response to other 

stakeholders. 
50

Characteristic A. Constrained Ideal Traffic 

System (CITS) 

B. Generally Above 

Average Systems 

that do not Meet 

CITS Criteria 

C. Traffic Systems 

with Below 

Average 

Performance 

Maintenance 

- Time to obtain 

indication of failure 

For systems in excess of 400 

intersections, 70% of failures 

should be detected by the 

operating agency, for fewer 

intersections, 30% of failures 

should be detected by the 

operating agency. 

Generally does not 

achieve CITS 

capability 

Generally does not 

achieve CITS 

capability 

- Time to respond after 

receiving an indication 

of controller or signal 

failure 

Within one hour during 

business hours. 

Within two hours during nonbusiness hours 

Within two hours 

during business hours. 

Within four hours 

during non-business 

hours. 

May be longer than 

for Column B. 

- Maintain detector 

operation 

Minimum of 95% of detectors 

operational. 

May not achieve 95% 

operability. 

Considerable 

percentage of 

detectors often 

inoperable 

- Maintenance 

Personnel 

qualifications 

Meet qualifications stated in 

Section 4 or well managed 

contractor support 

Objective is to meet 

CITS qualifications. 

Personnel with 

lesser qualifications 

or poorly managed 

contractor support. 

- Preventive 

Maintenance Formal program May have formal program 

Usually no program. 

May correct potential 

problems if observed 

as a result of 

inspection for other 

issues. 

Training 

Personnel planning 

Plan to assure that the 

number of required personnel 

will be available 

General staffing plan 

for budgeting purposes 

General staffing plan 

for budgeting 

purposes 

Support for Training 

- Support for training 

programs to achieve 

proficiency 

requirements 

- Support for 

specialized training 

- Support to 

achieve 

proficiency 

requirements 

varies 

significantly 

- Support for 

specialized 

training 

Support for 

specialized training 
51

References 

1. Tarnoff, P.J. and J. Ordonez, Signal Timing Practices and Procedures, Institute of 

Transportation Engineers, March, 204. 

2. Gordon, R. L. Systems Engineering Processes for Developing Traffic Signal Systems, 

NCHRP synthesis 307, Transportation research Board, 2003. 

3. Gordon, R.L. and Tighe, W., Traffic Control Systems Handbook, FHWA Report FHWAHOP-06-006, Federal highway Administration, October, 2005. 

4. Pline, J.L., Traffic Engineers Handbook, Institute of Transportation Engineers, 1999. 

5. National Traffic Signal Report Card – Technical Report 2007, National Transportation 

Operations Coalition. 

6. H.R. 1195: SAFETEA-LU Technical Corrections Act of 2008. 

7. Puget Sound Regional ITS Implementation Plan, Puget Sound Regional Council, August 7, 

2008.

8. Intelligent Transportation Systems for Traffic Signal Control, U.S. Department of 

Transportation.

9. Hood, W. Private communication.

10. Fee Estimate – Millennia Mall Retiming and Scope and Schedule-Millennia Mall Retiming 

(Bid submitted to the City of Orlando, FL in October 2005 by TEI Engineering). 

11. Row, S. and P. J. Tarnoff, USDOT, FHWA Traffic Signal Training Assessment –Summary 

Report, Institute Of Transportation Engineers, University of Maryland, June 29, 2005. 

12. Giblin, J.M. and W.H. Kraft, Traffic Control Systems Operations – Installation, Management 

and Maintenance, Institute of Transportation Engineers, 2000. 

13. Antonucci, et al, NCHRP Report 500, Guidance for Implementation of the AASTO Strategic 

Highway Safety Plan, Volume 12:A Guide for Reducing Collisions at Signalized 

Intersections, Transportation Research Board, Washington, D.C., 2004.

14. Making Intersections Safer:A Toolbox of Engineering Countermeasures to Reduce Red-Light 

Running, Federal Highway Administration/Institute of Transportation Engineers, 2003. 
A-1

Appendix A 

Questionnaire
A-2

TRAFFIC SIGNAL OPERATIONS AND MAINTENANCE STAFFING AND 

RESOURCE REQUIREMENTS GUIDELINES 

QUESTIONNAIRE 

May 16, 2008

Background: 

The 2005 Traffic Signal Report Card assigned a grade of D- nationally to traffic signal 

operations and maintenance practices. It is generally assumed that deficiencies in traffic signal 

operations and maintenance are the direct result of insufficient funding and staffing to optimally 

accomplish these tasks. While significant variability may exist among agencies in terms of 

system size, complexity, geography, demographics, locality, state, regional and local 

transportation priorities, politics and so forth; it is feasible that detailed guidance about staffing 

and resource based on functionality can be developed. The current guidance available is very 

general and not achievable for most jurisdictions. 

The ITE Traffic Engineering Handbook and Traffic Control System Operations: Installation, 

Management and Maintenance publication are often referred to when establishing staffing and 

resource requirements for traffic signal operations. These documents suggest labor requirements 

of 20 to 25 hours per intersection for traffic signal retiming and estimates as a rule of thumb that 

one traffic engineer is needed to properly operate and maintain every 75 to 100 signals and one 

technician to operate and maintain every 40 to 50 signals. As a rule of thumb these estimates 

are adequate; however the current transportation environment requires much more detailed 

estimates. 

The lack of a credible guideline for traffic signal operations and maintenance staffing and 

resource needs has resulted in the inefficient operation and maintenance of traffic signals on a 

national scale. Ineffective operation and maintenance of traffic signals has serious safety 

implications and contributes to thousands of hours of unnecessary traffic delays and congestion 

on both local and major arterial systems and road networks. An improved understanding of the 

relationship of performance to operations and maintenance resources expended is desired. 

The objective of this FHWA sponsored project is to develop a guideline to assist agencies in 

developing a staffing and resource plan to effectively operate and maintain traffic signal systems. 

Science Applications International Corporation (SAIC) and its sub-consultants, Dunn 

Engineering Associates and Kittelson Associates have been tasked by FHWA to conduct a study 

to establish these requirements. As part of this study we are conducting a series of in depth 

interviews to identify the operational and maintenance requirements for an ideal traffic system 

that must conform to real world constraints and resource limitations. The interviews are 

structured according to the questionnaire that follows. We appreciate your participation to help 

us accomplish this objective. 
A-3

Please provide the following information on the system and on the traffic signal operations that 

your agency is responsible for. 

A. Traffic Network Characteristics 

1. Number of signals in each type of network

Type of Network Grid Arterial Isolated 

Number of Signals 

2. % AADT growth per year

3. % signals  operating under saturated conditions during peak hour

4. % signals operating at saturated conditions for at least one    hour in excess of

peak hour

5. Type of jurisdiction (major city with large number of grid signals, suburban

jurisdiction with low population density, county with widely spaced

intersections, state DOT with wider expansive distance between intersections

(e.g. 50 miles or more)

6. % growth in signals/year

B. Classification of Signal System Characteristics

Please provide number or percentage of signals in each category (those items marked *

relate to signals that actually operate under the conditions described).

1. Adaptive (e.g. SCOOT, SCATS, OPAC, RHODES)*

2. Closed loop with data development tools (e.g. ACS Lite) including isolated

signals are controlled by this type of system*

3. Closed loop or central control (UTCS type) including isolated signals that are

controlled by this type of system*

4. Other type of interconnected system*

5. Isolated signals with automatic failure reporting*

6. Isolated signals without automatic failure reporting
A-4

7. Proximity of signals to maintenance facility

a. Number of signal within 5 miles of maintenance facility

b. Number of signals between 5 and 10 miles of maintenance facility

c. Number of signals greater than 10 miles from maintenance facility

8. Controller Classification

a. Number of 170 family controllers

b. Number ofATC/2070 family controllers

c. Number of NEMA TS1 controllers

d. Number of NEMA TS2 controllers

9. Age of field equipment

a. Number of controllers less than 5 years old

b. Number of controllers between 5 and 10 years old

c. Number of controllers greater than 10 years old

10. Indicate number of ancillary devices present

a. Preemption/priority

b. CCTV

c. Changeable message signs

d. UPS

11. Communications – Indicate number of signals controlled by following

a. 7 wire cable

b. Twisted wire pair

c. Fiber optics  

d. Coaxial cable

e. Wireless

f. Non‐owned communication service (identify)
A-5

C. Redundancy Characteristics of System

1. Redundancy of central controls

2. Redundancy in backbone communications to field

3. Redundancy in distribution communications to field

D. Traffic Detection

1. Type and extent of detection

Number of Each Detector Type 

Inductive 

Loop 

Video 

Processo

r Detector 

Radar, 

Microwave Other 

Number 

of 

Detectors 

Actually 

Operatin

g 

Local 

actuation 

detectors 

 

System 

detectors 

 

2. Are detectors periodically checked for operability (in the case of video processor

detectors are they checked under poor lighting and weather conditions)

3. Is detector data analyzed on a regular basis?  How is the data used?

4. CCTV

a. How many cameras are available

b. Is CCTV monitoring used to support

1. On line adjustment of timing plans

2. Planning for signal timing/phasing

3. Incident management
A-6

E. Timing Plan Characteristics 

1. Number of daily timing plans

2. Other periodic timing plans (e.g. weekends, special events)

3. Non‐periodic timing plans (e.g. diversion, emergency evacuations)

F. Operations Characteristics

1. Frequency of timing plan updates, phasing plan checks, warrant reviews

2. Is a staffed TMC used, if so what is the operating period

3. Co‐location with other traffic operations or police agencies

G. Maintenance Practices

1. Allowable time to repair signal failure during business hours

2. Allowable time to repair signal failure during non‐business hours

3. Allowable time to repair ancillary equipment (detectors, preemption equipment,

etc.)

4. Allowable time to repair communications

5. Availability (Up‐time) for central equipment

6. Identify routine maintenance practices

7. Actual time to repair signal failure during business hours

8. Actual time to repair signal failure during non‐business hours

9. Actual time to repair ancillary equipment (detectors, preemption equipment,

etc.)  

10. Controller failures per year

H. Resource Issues
A-7

1. Budgets and personnel (including consultants). Please provide operating,

maintenance and capital (only for signal system) budgets for following items.  Please

provide person hours for each of the items

a. Management budgets and personnel hours for each of: supervision, planning, 

system engineering 

b. Operations budgets and personnel hours for each of (TOC operations, signal

timing including data collection)

c. Maintenance

1. Maintenance of signals (department budgets, contract budgets, personnel)

2. Maintenance of other equipment (detectors, preemption equipment, etc.)(

department budgets, contract budgets, personnel)  

d. Training

1. Does the agency have a formal training plan?

2. Does the agency provide the cost for training?

3. What training resources are available locally?

4. Is IMSA certification required for maintenance personnel

5. Is PTOE/PE certification required for engineering personnel

6. Percentage of operating budges spent for training.  

7. Type of operations training

8. Percentage of maintenance budget spent for training.  

9. Type of maintenance training

e. Growth – Do O & M budgets increase with signal growth on an annual basis?

2. Practices and Constraints. Please identify the practices that are used that pertain to

the following items and please identify whether the practices are discretionary or are

required by the agency:

a. Use of owned or leased communication facilities

b. Use of own staff or contract maintenance

c. Use of own staff or consultants for engineering
A-8

I. Staffing Issues   

1. Pay as compared with peer agencies in the region (higher, approximately the same,

lower)

2. What is the average tenure of engineering employees?

3. What is the average tenure of maintenance employees?

4. What is the number of vacant engineering and maintenance positions

J. Management  

1. Is a  mission statement available

2. Is a concept of operations available

3. Are operations procedures available  

K. Staff Capability Level

Position 

Number of 

Personnel in 

Position 

Qualifications – 

Training/experience level 

Management 

Traffic Signal Engineer 

Traffic Signal Analyst/Technician 

ITS Engineer 

Traffic Signal Maintenance 

Technician 

 

Electronic Specialists 

TMC Operators 

Public Relations Coordinator 

L. Objectives and Performance Measurement
A-9

1. Please complete Table 1

2. Are summary performance reports prepared and reviewed periodically

M. Planning Issues

1. What causes the staff size to change  

2. Is your funding stream reliable

3. How far into the future do you plan

4. What upgrades or updates do you plan

5. Do you have planning documentation that is available for review? Examples include

business plans, resource models, maintenance check lists, concept of  operations  

N. Communication to the Public

Do you provide information on incidents, construction, special events and congestion

through:

1. Changeable message signs

2. Website

3. Media

4. Other

O. Feedback from the Public  

1. Do you seek feedback from the public on its perception of agency performance

through such means as surveys or other proactive techniques.  If so please identify

the technique

2. Do you have a telephone hotline or a website that facilitates feedback from the

public.
A-10

TABLE 1 OBJECTIVES AND MEASURES 

POSSIBLE 

OBJECTIVE 

DOES 

OBJECTIVE 

PERTAIN TO 

YOUR 

AGENCY 

(Y/N) 

ESTIMATE OF 

RELATIVE 

IMPORTANCE (5 is 

very important, 1 is not 

important) 

EXAMPLE OF 

MEASURE FOR 

OBJECTIVE 

MEASURES 

USED BY YOUR 

AGENCY 

 

1. Reduce delay and 

fuel consumption for 

normal traffic patterns. 

 a) Vehicle hours delay. 

b) Gallons fuel 

reduced. 

2. Reduce delay and 

fuel consumption for 

incident conditions. 

 Same as 1. 

3. Reduce emissions. Kg of CO, NOX, SO2, 

CO2. 

4. Reduce accidents 

resulting from signal 

outages. 

 Accidents reduced. 

5. Reduce secondary 

accidents resulting 

from incidents. 

 Same as 4. 

6. Improved public 

perception of signal 

and management center 

operations. 

 Rating scale. 

7. Serve as a diversion 

route for corridor 

operations. 

 Same as 1 and 3. 

8. Provide preemption 

for emergency vehicles 

and railroads. 

 a) Number of 

emergency vehicles 

provided 

preemption. 

b) Negative impact on 

general traffic. 

9. Provide transit 

priority. 

 a) Traveler hours 

reduced. 

b) Improvement in 

schedule 

c) Adherence. 

10. Support emergency 

evacuations. 

 Availability of plans. 

11. Provide traffic 

information to public 

and private traffic 

information services. 

 Checklist for information 

supplied. 

12. Data for planning 

and evaluation. 

 Employment of data by 

agency or MPO. 

13. Improve internal 

efficiency of 

department operations. 

 
B-1

    Appendix B 

Survey Responses 
B-2

Appendix B - Survey Responses (Cont.)

AgencyRedundancy Characteristics of SystemRedundancy of central controlsRedundancy in backbone communications to fieldRedundancy in distribution communications to fieldTraffic Detection

Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive 

Loop

Video Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop V

PD

Local actuation detectors 2200 125 0 0 98% 1% 1% 0 <20 0 Everything else 10 60% 40% All other 

System detectors 260 15 0 0 0 0 0 100% 1500 Number of Detectors Actually Operating:Local actuation detectorsSystem detectors

Are detectors periodically checked for operability (in the case of video processor detectors are they checked under poor lighting and weather conditions)Typical detector configuration % of intersections that operate Fully Actuated: Advanced & limit line detection on main street, limit line detection on side street approaches % of intersections that operate Fully Actuated: Advanced detection on main street & limit line on side street.% of intersections that operate SemiActuated: No detection on main street, limit line detection on side street. % of intersections that opeate with no detectionIs detector data analyzed on a regular basis? How is the data used?CCTVHow many cameras are availableIs CCTV monitoring used to support:On line adjustment of timing plansPlanning for signal timing/phasing

Incident managementTiming plan characteristicsNumber of daily timing plans 

Other periodic timing plans (e.g. weekends, special events) Non-periodic timing plans (e.g. diversion, emergency evacuations) 

Operations characteristics

Frequency of timing plan updates, phasing plan checks, warrant reviews

Is a staffed TMC used, if so what is the operating periodCo-location with other traffic operations or police agencies

YesYesAs required72175YesTo look at on the spot traffic flow, real time volume, peak hours, and yearly trends in ADT'sYes, annuallyNumber of Each Detector TypeAll but approx. 502 servers, 1 spare communications server

No5-7 years7:30 am - 4 pmon yearly pm's and maintenance visits75%12%

Some alternate paths

timings are reviewecameras. We do no20 hours a day 7 dayes Transit in same located in PSCC wit

Goal is every 3 years0700-1900, and during special eventsNo

Signals retimed every 2 years, no warrant reviewstraffic engineer works out of TMC, but not with specific staffing hoursYes

Major every two – three years6am – 9pmNone

6 am to 6 pm weekdaysYes, state freeway management system, state police

A C

Limited, utilize radio communications for longer duration & significant failures of twisted pair 

Some alternate paths

Number of Each Detector Type

4 to 62 to 4150%

Number of Each Detector Type

yesThrough PM’s and routine monitoring of Central System Software features23002 CCTV, 8 dial-upyes

Type and extent of detection

Software/Server based, can be transferred to backup if necessaryNot ApplicableMajority of center to field communication by PSTN2751%98%1%

D

starting to implement Ethernet backbone with rerouting

Number of Each Detector Type

95%Yes for inductive loops100%No7YesYesYesSix (am, am off-peak, midday, midday off-peak, pm, pm off-peak)Holiday plans around shopping areas; special event plans around Ampitheater, occasional marathon or bike race special plansHeavy volume plans available for implementation when necessary

E

Number of Each Detector TypeWhen complaints are made30%70%No. Detector data is not used.60YesYesYes4YesYes

Backup data hourlyfull redundant hot swThat is beyond our redundancy due to Minimal

Number of Each D

All other400No due to limited st5%5%75%20%, CBD areas - 2 Not at this time due 180YesYesYesTypical 3 dial operaWeekend peak and Emergency evac pla

B

00095%0%13%No0three to fivetwo to three0
B-3

Appendix B - Survey Responses

AgencyTraffic Network Characteristics

Grid Arterial Isolated Grid Arterial Isolated Grid Arterial Isolated Grid Arterial Isolated Grid Arterial Isolated Grid Arteri

390 314 76 135 415 451 85 362 175 0 25 90 180 80 40 200 525 

% AADT growth per year% signals operating under saturated conditions during peak hour% signals operating at saturated conditions for at least one hour in excess of peak hourType of jurisdiction % growth in signals/yearClassification of Signal System CharacteristicsAdaptive (e.g. SCOOT, SCATS, OPAC, RHODES)*Closed loop with data development tools (e.g. ACS Lite) including isolated signals are controlled by this type of system*Closed loop or central control (UTCS type) including isolated signals that are controlled by this type of system*Other type of interconnected system*Isolated signals with automatic failure reporting*Isolated signals without automatic failure reportingProximity of signals to maintenance facilityNumber of signal within 5 miles of maintenance facilityNumber of signals between 5 and 10 miles of maintenance facilityNumber of signals greater than 10 miles from maintenance facility Controller ClassificationNumber of 170 family controllersNumber ofATC/2070 family controllers Number of NEMA TS1 controllersNumber of NEMA TS2 controllersAge of field equipmentNumber of controllers less than 5 years oldNumber of controllers between 5 and 10 years oldNumber of controllers greater than 10 years oldNumber of ancillary devices presentPreemption/priorityCCTVChangeable message signsUPSCommunications – Number of signals controlled by following7 wire cable Twisted wire pairFiber opticsCoaxial cableWirelessNon-owned communication service (identify)* relate to signals that actually operate under the conditions described

193 directly; 319 remotely08040305000275125600501506257545000550Major City

B

80025 locations have Fire hou180No static VMS, 5 portablesZero now but beginning a 600200800500100200800

N/A

40

50

5-10 new signals per year

70130017016013801201000Approx. 180Approx. 1200Approx. 170Approx. 120Approx. 10NoneApprox. 60NoneNoneSiemens' ACTRA system200

150

Major City1%

E

3%-5%

7000DSL service - 1 (connects to closed loop fiber system); dial up phone connecting to fiber system - 2; dial up phone to isolated system - 1900Approx. 6090115001123about 100about 1500030%0070%Approx. 15%

5%

mid-size suburban cityApprox. 4%

D

Approx. 2-4%

Number of signals in each type of network

305

None2925None4005020320Leased-lineNone1840%60%150257nonenone767657

A

NoneNone

Varies by roadway; Annual Count Report published on website - http://www.leecounty.com/publicworks/Traffic/2007%20Count%20Report2.pdf.

Approximately 30%

Approximately 30%

County6%Operate approximately 12% in Traffic Responsive.None314

C

1%3.20%0.80%County (responsible for City suburbs, some state signals, and rural signals<1.0%.NoneAries - 47 signalsTranscore - 405 signalsHardwire - 7 signalsNoneNon-system - 175Approx. 481Approx. 125Approx. 20NoneNone222405Approx. 60Approx. 345Approx. 222351752None1020 on Aries1001037
B-4

Appendix B - Survey Responses (Cont.)

AgencyRedundancy Characteristics of SystemRedundancy of central controlsRedundancy in backbone communications to fieldRedundancy in distribution communications to fieldTraffic Detection

Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive 

Loop

Video Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop Video 

Processor Detector

Radar, Microwave

Other Inductive Loop Video 

ProcessDetecto

Local actuation detectors 2200 125 0 0 98% 1% 1% 0 <20 0 Everything else 10 60% 40% All other 100 

System detectors 260 15 0 0 0 0 0 100% 1500 Number of Detectors Actually Operating:Local actuation detectorsSystem detectors

Are detectors periodically checked for operability (in the case of video processor detectors are they checked under poor lighting and weather conditions)Typical detector configuration % of intersections that operate Fully Actuated: Advanced & limit line detection on main street, limit line detection on side street approaches % of intersections that operate Fully Actuated: Advanced detection on main street & limit line on side street.% of intersections that operate SemiActuated: No detection on main street, limit line detection on side street. % of intersections that opeate with no detectionIs detector data analyzed on a regular basis? How is the data used?CCTVHow many cameras are availableIs CCTV monitoring used to support:On line adjustment of timing plansPlanning for signal timing/phasing

Incident managementTiming plan characteristicsNumber of daily timing plans 

Other periodic timing plans (e.g. weekends, special events) Non-periodic timing plans (e.g. diversion, emergency evacuations) 

Operations characteristics

Frequency of timing plan updates, phasing plan checks, warrant reviews

Is a staffed TMC used, if so what is the operating periodCo-location with other traffic operations or police agencies

YesYesAs required72175YesTo look at on the spot traffic flow, real time volume, peak hours, and yearly trends in ADT'sYes, annuallyNumber of Each Detector TypeAll but approx. 502 servers, 1 spare communications server

No5-7 years7:30 am - 4 pmon yearly pm's and maintenance visits75%12%

Some alternate paths

timings are reviewed daily cameras. We do not do wa20 hours a day 7 days a weyes Transit in same room alocated in PSCC with 9-1-1 

Goal is every 3 years0700-1900, and during special eventsNo

Signals retimed every 2 years, no warrant reviewstraffic engineer works out of TMC, but not with specific staffing hoursYes

Major every two – three years6am – 9pmNone

6 am to 6 pm weekdaysYes, state freeway management system, state police

A C

Limited, utilize radio communications for longer duration & significant failures of twisted pair 

Some alternate paths

Number of Each Detector Type

4 to 62 to 4150%

Number of Each Detector Type

yesThrough PM’s and routine monitoring of Central System Software features23002 CCTV, 8 dial-upyes

Type and extent of detection

Software/Server based, can be transferred to backup if necessaryNot ApplicableMajority of center to field communication by PSTN2751%98%1%

D

starting to implement Ethernet backbone with rerouting

Number of Each Detector Type

95%Yes for inductive loops100%No7YesYesYesSix (am, am off-peak, midday, midday off-peak, pm, pm off-peak)Holiday plans around shopping areas; special event plans around Ampitheater, occasional marathon or bike race special plansHeavy volume plans available for implementation when necessary

E

Number of Each Detector TypeWhen complaints are made30%70%No. Detector data is not used.60YesYesYes4YesYes

Backup data hourly, and offull redundant hot swapThat is beyond our control. redundancy due to CountyMinimal

Number of Each Detecto

All other400No due to limited staffing r5%5%75%20%, CBD areas - 2 large Not at this time due to old s180YesYesYesTypical 3 dial operations AWeekend peak and off peaEmergency evac plans and 

B

00095%0%13%No0three to fivetwo to three0
B-5

Appendix B - Survey Responses (Cont.)

Agency

Maintenance practicesAllowable time to repair signal failure during business hoursAllowable time to repair signal failure during non-business hoursAllowable time to repair ancillary equipment (detectors, preemption equipment, etc.)Allowable time to repair communicationsAvailability (Up-time) for central equipmentIdentify routine maintenance practicesActual time to repair signal failure during business hoursActual time to repair signal failure during non-business hoursActual time to repair ancillary equipment (detectors, preemption equipment, etc.)Controller failures per yearResource issuesBudgets and personnel (including consultants). Management budgets and personnel hours for each of: supervision, planning, system engineering Operations budgets and personnel hours for each of (TOC operations, signal timing including data collection) MaintenanceMaintenance of signals (department budgets, contract budgets, personnel)Maintenance of other equipment (detectors, preemption equipment, etc.)( department budgets, contract budgets, personnel)TrainingDoes the agency have a formal training plan?Does the agency provide the cost for training?What training resources are available locally?Is IMSA certification required for maintenance personnelIs PTOE/PE certification required for engineering personnelPercentage of operating budges spent for training. Type of operations trainingPercentage of maintenance budget spent for training. Type of maintenance trainingGrowth – Do O & M budgets increase with signal growth on an annual basis?Practices and ConstraintsUse of owned or leased communication facilitiesUse of own staff or contract maintenanceUse of own staff or consultants for engineering Discretionary

NoDiscretionaryDiscretionaryYesCommunity college and university coursesYesYes<60 min< 2 hours

B

We use all our own copper acircuits we lease but those wour new signal systemBothBothNoneOn job trainingNot by much, it is hard to get New construction is easierNoNoLess than 1%On job trainingNoYes minimal budget less thaITE, IMSA, We do have 1 ATMS engineseveral general and CIP fundbudget is about $800,000 thavehicle charges and benefitsThis work is performed by in our Signal Shop. The TMC g$800,000 that mostly covers and benefitsThis work is performed by in our Signal Shop. The generaaccounts for equipment is astuffDepends on equipementRoutine failures due to stormTheses functions come from budgets and most are not sphave to alter people’s work ato complete things99.9999%30 minutes or lessUnder an hour and half30 minutes30 minutes to 1 hourPre-empt is more important tand stuff can be a year or m30 minutes when possible

F

RequiredDesired, not requiredFor principal engineers and higher0%NoneNoDiscretionaryNoneInternal, on as needed basisNoNoNone2 hours - 2-3 days10-20 per year1-2 hours1-3 hours1 hour2 hours2 weeks2-3 days

E

allowed

all in-houseNo, but most haveunavailableunavailableunavailablesome of eachunavailableunavailableroughlyunavailableunavailablevaries3 this year100%no policydepends on the problem, crews respond immediately upon callon-call techs will arrive within an hour, time to fix depends on problemASAP1 hrno policyno policy

A D

24484824/71224Estimated average is 4 per /year$230,000$897,000$100,000YesTOC approximately $190k, Signal timing approximately $125,000.yesIMSAYesNo1%1%Generally as funds are available

Discontinuing

Use of own staffLimited use of consultants

C 
B-6

Appendix B - Survey Responses (Cont.)

AgencyStaffing Issues Pay as compared with peer agencies in the region (higher, approximately the same, lower) What is the average tenure of engineering employees?What is the average tenure of maintenance employees?What is the number of vacant engineering and maintenance positions Management

Is a mission statement available?

Is a concept of operations available?Are operations procedures available?Staff capability levelPosition Number of 

Personnel in Position

Number of Personnel in Position

Number of Personnel in Position

Number of Personnel in Position

Number of Personnel in Position

Number of Personnel in Position

Management 1.5 1 121

Traffic Signal Engineer 1.5 1 123Traffic Signal Analyst/Technician

2 0 1 5

These are the 

TMC techs

ITS Engineer 0.5 0 011Traffic Signal Maintenance Technician 7-techs, 3-Sr 

techs 12 6 5 14

Electronic Specialists None 4 0TMC Operators 2.5 1 047Public Relations Coordinator 1 0 0Objectives and Performance MeasurementSee Table 1Are summary performance reports prepared and reviewed periodically?Planning IssuesWhat causes the staff size to change?Is your funding stream reliable?How far into the future do you planWhat upgrades or updates do you plan?

Do you have planning documentation 

that is available for review? Examples include business plans, resource models, maintenance check lists, concept of operations

Communication to the PublicDo you provide information on incidents, construction, special events and congestion through:Changeable message signsWebsiteMediaOtherFeedback from the PublicDo you seek feedback from the public on its perception of agency performance through such means as surveys or other proactive techniques. If so please identify the techniqueDo you have a telephone hotline or a website that facilitates feedback from the public

Qualifications – 

Training/experience level

C

Updates to control equipment, major PM’s updates to operations center, routine signal timing updatesYesFor operations center, under developmentYes6.5yrs0 engineering, 2 maintenanceGrowth3-5 yrsPortable Message Signs used as necessaryYesYes, SOC phone # and Rrequest for action program

A

Yes

3yrs Electrical exp min. IMSA II 

signals, IMOT

Unavailable12yrs

D

Qualifications – 

Training/experience level

approx. the same5-10 years5-20 years0nonono

Qualifications – 

Training/experience level

PE, 10+ years

PE, PTOE, 10+ years

10+ years

varies

annuallyNopretty constantyes2-5 yearsSurveysyes, both

E

YesYesroadway improvementsNo

Approx. the same>10 years>10 years0NoNoNo

Qualifications – 

Training/experience level

YesThe City's website is used. Citizens can enter questions, complaints, and comments to staff.See aboveNot yetNot yet

Slightly above peers, but 10 years10 years2YesNoNo

Tr

NoNo telephone hot line due Divisions have phone numpeople can contact us

B

TARS sitesNew signal system is whanext 6 yearsCon Ops and RequireOur feedback comes from We also get feedback frowithPeople leaving, vacationsYesWe try to plan 5 years ouonly 2 years

lower3YesNoYes

Qualifications – 

Training/experience level

minimallyresignationsYes5 yearsITS upgradesMaster Plan on local MPO websiteYesMail out surveys
C-1

Appendix C 

Frequency of Signal Retiming 
C-2

The need for signal retiming or rephasing may result from the following: 

• Change in population level and car ownership in the region 

• Change in land use that changes traffic demand. 

• Change in traffic patterns resulting from changes in the highway network. 

• Change in traffic operations such as corridor management plans. 

• Change in motorist driving patterns resulting from increased emphasis on corridor 

management, use of transit or car-pooling. 

Many agencies have reported a wide range of benefits and benefit to cost ratios resulting from 

signal retiming. Because of differences in evaluation methods and periods between retiming it is 

difficult to provide a general benefit figure except to say that it usually exceeds the cost of 

retiming by many times and usually results in a significant reduction in delay and fuel 

consumption. 

Figure 1 (1) shows a general concept for assessing the benefits of signal retiming as a function of 

time. The figure shows that after three years the benefits begin to increase significantly. 

Swayampakala and Graham (2) studied the benefits of retiming signals at varying time intervals 

for a number of intersections in several cities in North Carolina. They calculated delay using 

SYNCHRO runs based on collected turning movement counts. The benefit is computed as the 

saving in delay less the cost of retiming. Figures 2, 3 and 4 show the results of the research. 

Retiming intervals in the figures are shown in months. The results vary widely from location to 

location. No pattern can be observed with different rates of change in traffic volumes. 

Swayampakala and Graham conclude that the suggested time period for signal retiming is 24 to 

30 months. Parsonson (3) recommends a one to three year time interval. 

The NTOC survey data responding to the question “Does your agency conduct a comprehensive 

review of area-wide or corridor signal timing at least every 3 years or sooner if justified” was 

analyzed. A score of 5 corresponds to retiming every 3 to 5 years. The scores are as follows: 

Score Percentage 

5 12 

4 24 

3 25 

2 19 

1 18 
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Thus, a relatively small number of agencies retime the signals at 3 to 5 year intervals or sooner. 

A 30 to 36 month time period for the constrained system would therefore appear to capture most 

of the benefits indicated by prior research, while still setting an achievable goal for operating 

agencies. 
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REFERENCES

1. Sunkari, S. “The Benefits of Retiming Traffic Signals”, ITE Journal, April 2004, pp 26‐29.

2. Swayampakala, R.K. and J.R. Graham, “Optimum Time Intervals fir the Traffic Signal

Re‐Timing Process, presented at the 2004 Annual Meeting of the Transportation

Research Board.

3. Parsonson, P. “Signal Timing Improvement Practices.”    In Synthesis of Highway

Practice, No. 172, TRB, pp 1‐10.
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Appendix D 

North Central Texas Council of 

Governments Ranking Model 
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This appendix is largely abstracted from the reference. 

The NCTCOG ranking model is based on the existing traffic conditions. The variables used in 

the model and their weights are discussed in this section. 

Variables

Total delay

Delay is the most frequently used measure of effectiveness for signalized intersections. Delay 

can be quantified in many different ways: stopped time delay, approach delay, travel time delay 

and time-in-queue delay (McShane and Roess, 1998). Travel time delay is used in this research. 

Travel time delay of an individual vehicle is the difference between the measured travel time and 

the travel time at the desired speed. Measured travel time is taken as an average of travel time in 

both directions of travel. The desired speed is taken as the posted speed. In this model, delay is 

used on an aggregate basis, and it is calculated below: 

DPV = delay/vehicle/intersection  

= (measured travel time - desired travel time)/ (number of intersections) (1) 

Total delay/ intersection = DPV x ADT (2) 

Where ADT is the average daily traffic. 

Number of Stops

The number of stops is taken as the average of the number of stops counted in both directions of 

travel along the corridor. To get the aggregate value, this average value per intersection is 

multiplied by the ADT. 

Number of stops per intersection =

(Number of stops/number of intersections) x ADT (3) 

System type

There are three types of existing systems. A value of one indicates that all intersections are part 

of an existing interconnected system with communications. A value of two indicates that some 

but not all intersections are part of an existing interconnected system with communications. A 

value of three indicates that there is no system (currently an isolated operation). 

Weightings

The weighting for each factor is allocated by an expert group. The weightings are presented in 

Table 1. 
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Table 1 

Variables and Weightings

Variable Weighting 

Total Delay (DELAY) 50 

# of stops (STOPS) 30 

System type (SYSTEMTYPE) 20 

Calculation of Rank Order

Using the weightings applied by the NCTCOG, the following equation is developed. 

Total Score(s) = (Delay /Max(Delay))•50 + (Stops/Max(Stops))•30 + System_Type•20 (4) 

Where System_Type = 1.0 for type 1 (all signals interconnected)

0.5 for type 2 (some signals interconnected)

0 for type 3 (all signals isolated)

Quantitative variables DELAY and STOPS are normalized by dividing by the maximum value 

from all of the candidate corridors, which precludes any single variable dominating the total 

score because of its magnitude relative to the other variables. After normalization, each variable 

is expressed on a zero-to-one scale and the weights are an expression of the relative importance 

of each criterion.. The maximum value of a variable in the given data is used for normalization. 
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REFERENCE 

Pulipati, S.B., “Regional Prioritization of Corridors for Traffic Signal Retiming, University of 

Texas Arlington. 
Traffic Signal Operations and Maintenance

Staffing Guidelines

U.S. Department of Transportation 

Federal Highway Administration 

Office of Operations 

1200 New Jersey Ave., SE 

Washington, DC 20590 

Toll-Free "Help Line" 866-367-7487 

FHWA-HOP-09-006