902.4 Signal Installations and Equipment
From Engineering Policy Guide
902.4.1 New Signal Installations
Guidance. Normal procedure for installation of traffic control signals, after having been found warranted and justified, is to provide for their installation through normal construction programming. If the need for a traffic signal becomes a matter of urgency, signals can be considered for installation through department forces, contract, or a combination of the two. It is in no way considered as a replacement for the normal construction programmed signal installation. In addition, warranted signals can be installed at developments by permit.
After it has been identified that signals are needed at an intersection, it will be necessary to identify funding for the installation. The type of installation and the source of funding will depend on many factors. It is usually necessary to develop a priority list of intersections, since funding is not available to signalize every intersection that meets signal warrants. District Traffic will determine the signal control type before design of the preliminary signal layout is started.
902.4.1.1 Conditions for installation by permit
Guidance. When an installation is warranted and justified under any of the warrants in this policy and if the owner of the commercial establishment desires the traffic signal to be installed in advance of the time it can be scheduled for installation by the department, the owner can apply for a permit for such installation. The following conditions will apply:
Standard. The applicants shall provide a complete design of intersection. Design features shall be in accordance with Commission design practices. Plans shall be prepared by a qualified engineer and developed under MoDOT's guidelines and shall require approval by the department.
Geometric improvements shall be constructed in accordance with Commission's standards and specifications.
The applicant shall pay all costs for the permanent signal installation and any required geometric improvements. The Commission will provide electrical power, maintenance of the signal after it is completed and accepted and future replacement if needed, all at no cost to the applicant. Upon completion and acceptance of the installation, the signal and all appurtenances shall become the property of the state.
An agreement with the Commission for the installation of the traffic signal shall be executed as part of the permit. The standard contract Agreement for the Installation of a Traffic Signal by Others to be Maintained by the Commission is available.
Support. Refer to EPG 902.17 for additional information on execution of contracts.
902.4.1.2 Permanent Signals
Guidance. Permanent signals are installations using steel mast arm poles, underground conduit and basic intersection lighting. Permanent signal installations are preferable to span wire signal installations, but each case is decided on its own merits and the funding available.
The signals, lighting and intersection geometrics are constructed according to current Design standards. Permanent signals are typically installed with construction projects or at locations where there are no programmed major roadway projects that would affect the signals.
902.4.1.3 Span Wire Signals
Guidance. Span wire signals are installed with wood or steel span wire poles and overhead wiring. A steel span wire post is recommended where guy wires for a wood pole cannot be used, especially for long spans.
Span wire signals can be installed by contract, by MoDOT forces or a combination of the two. Span wire signals are typically installed where signals are needed sooner than permanent signals can be programmed. This can occur where there is a future construction project that will install signals or where there is no work currently programmed. If no work is programmed, it might be advantageous to pursue the programming of a permanent signal installation to replace the span wire signals.
Standard. Diagonal span wire signals shall not be used. Span wire signals are to be installed with basic lighting on the signal poles (silhouette lighting) unless other basic lighting is in place.
A pole on state right of way owned by others shall not be used to support span wire signals. If an adjustment of the location for a department installed pole cannot be made, the existing pole shall be moved at the expense of the owner.
902.4.1.4 Installation Cost of Signals
Standard. If the need is established by a traffic study and the intersection meets a warrant(s), a method of funding the installation shall be determined.
Guidance. Ideally, a signal to be installed will be placed upon the Right of Way and Construction Program but other methods of funding may be available.
902.4.1.4.1 Right of Way and Construction Funding
Guidance. The installation of permanent signals could be funded by right of way and construction funds.
Standard. For new construction or programmed major improvements, intersections that are currently signalized or meet warrants for signals shall have permanent signals included in the design.
Option. If no improvements are programmed, it may be possible to program permanent signal installations.
Support. Contact district Design or Planning for information on status of programmed projects or the possibility of programming signals. In some cases, signals could be installed on a high hazard project that is also part of the right of way and construction program.
902.4.1.4.2 District Funding
Option. It may become necessary to install signals prior to the time they can be provided through the normal Right of Way and Construction Program. Intersections that satisfy the warrants described in EPG 902.3, may qualify for the installation of signals with internal funds.
902.4.1.4.3 Funding by Others
Guidance. If an industrial plant, factory, or commercial entrance meets a warrant for signal installation, the owner can provide, at no cost to MoDOT, the traffic signal and the intersection geometric improvements.
Standard. Signalization and geometric improvements shall be designed and constructed in accordance with existing MoDOT design standards and a permit shall be required. The traffic signal, after installation, becomes the property of MoDOT. At no cost to the owner, MoDOT shall provide power, maintain, replace or upgrade the traffic signal. Work zone traffic control for intersection improvements shall also be in accordance with existing MoDOT design standards.
Guidance. These installations of permanent signals are usually completed through the permit process. When a design project is in an area where a commercial entrance meets signal warrants, MoDOT is to install signals.
At locations where peak hour commercial signals are being installed, advanced flashers with applicable advanced warning signing are to be installed.
The policies for school signals, fire station signals and other special signal installations are covered in later sections.
902.4.2 Controllers and Equipment
902.4.2.1 Controller and Cabinet Replacement Program
Guidance. Routine replacement of control equipment assists in maintaining and operating a reliable system. Signal controllers should be replaced at 10 years of age or older and cabinets should be replaced at 20 years of age or older.
Option. Cabinets and controllers may be replaced sooner than the recommended age. Controllers or cabinets experiencing higher than normal maintenance should be considered for replacement regardless of age.
902.4.2.2 Approved Products Lists and Equipment Evaluations
Support. MoDOT has developed an Approved Products List (APL) containing many items used in signals and lighting. The APL is based on equipment that meets department specifications and has been tested for a specified test period with satisfactory performance. This list helps MoDOT purchase reliable products for traffic signals and highway lighting. This list is included in the bid requests for applicable equipment purchases and is also included in construction contracts that include signals or lighting.
MoDOT frequently tests new products and equipment for signals. These new products can be installed on a construction project, purchased on parts orders or with controller orders. Only a limited number of units will be accepted for test statewide until an item is added to the approved products list.
Standard. All equipment evaluations are coordinated through Traffic and are reviewed by the Traffic Signal Quality Circle. The vendor supplying the equipment must fill out the New Product Evaluation Form and provide equipment specifications and a certification that the equipment meets MoDOT specifications before the test is performed. The equipment is tested for the period specified on the approved products list.
Option. Products that are not performing satisfactorily may be replaced at any time if the vendor cannot provide timely correction of the problem or if unsatisfactory operation of the intersection results.
Standard. Upon completion of the test, the district shall complete the Product Evaluation Form - Signal and Lighting Equipment and submit it to Traffic. The evaluation is reviewed by the Traffic Signal Quality Circle for addition to the APL or for rejection.
If a vendor is proposing a product that does not meet department specifications, the vendor shall provide a written explanation to Traffic of why the product does not meet the current specifications and why the product should be evaluated. If approved for evaluation, the product is tested for the specified period as described above. After evaluation and if the product is satisfactory, Traffic will consider making a recommendation to revise the applicable specifications. If specifications are not revised, then the products that does not meet specifications will not be added to the approved products list.
902.4.2.3 Experimental Equipment
Guidance. MoDOT often evaluates experimental equipment for traffic signals. Experimental equipment can be new products or products that vary considerably from our current standards or practices. The evaluation of experimental products can be initiated by district or Central Office staff, as part of a research project, as an implementation of an employee idea, etc.
The evaluation of experimental equipment for traffic signals is coordinated through Traffic and may involve other functional units such as Organizational Results. If the evaluation is part of a research project, then the project will provide guidelines for testing. Products can be evaluated in a similar manner to that described in EPG 902.4.2.2 Some items to consider before evaluating experimental equipment are as follows:
- What improvement will the equipment provide?
- Does the equipment conform to National and State standards?
- Is the equipment cost effective?
- Are funds available?
- What are the advantages and disadvantages of the equipment?
- How will the effectiveness of the equipment be tracked?
- What criteria will be used to determine if the equipment is satisfactory?
The Product Evaluation Form – Signal and Lighting Equipment can be used for evaluation of experimental equipment.
902.4.3 Annual Orders and District Signal and Lighting Equipment Purchases
Guidance. Traffic Division will coordinate annual orders for signal and lighting equipment purchases. The intent of annual orders is to combine orders from all districts to develop larger quantities and to save duplication of work.
Standard. Annual orders are limited to items that will be purchased in larger quantities and can be bid competitively. For signal and lighting annual orders, it is important that only these types of items be included in the requests. Proprietary items, model specific replacement parts, and small quantity items are to be purchased at the district level.
Option. There are many common "off-the-shelf" items that can be purchased at local suppliers, saving time, and in many cases money. Traffic staff may ask the districts to order some items from annual orders on their own if it does not appear they will benefit from the annual order process.
Standard. District purchases are to follow General Services’ guidelines for purchasing.
Support. Some information that General Services might need to include in equipment bids are:
- Reference to the Standard Specifications (if applicable). Indicate the exact section that applies.
- Reference to the approved products list (if applicable). Include a copy of the current list.
- Supplemental specifications (if applicable). Include a copy of the specifications. An example is signal controller purchases. Traffic maintains supplemental purchase specifications for controllers and other items.