902.26 Construction Inspection Guidelines for Sec 902 - Revision history

Hoskir: Renamed, renumbered and updated article due to MUTCD updates (See Special Ballot)

2026-01-05T17:34:27Z

Renamed, renumbered and updated article due to MUTCD updates (See Special Ballot)

Hoskir: Hoskir moved page 902.19 Construction Inspection Guidelines for Sec 902 to 902.26 Construction Inspection Guidelines for Sec 902: renumbered and renamed due to MUTCD Update (See Special Ballot)

2026-01-05T17:33:39Z

Hoskir moved page 902.19 Construction Inspection Guidelines for Sec 902 to 902.26 Construction Inspection Guidelines for Sec 902: renumbered and renamed due to MUTCD Update (See Special Ballot)

← Older revision	Revision as of 12:33, 5 January 2026
(No difference)

Smithk at 19:52, 26 October 2021

2021-10-26T19:52:15Z

← Older revision		Revision as of 14:52, 26 October 2021
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	==Staking==		==Staking==
	Staking and layout work for a traffic signal project should be done with the idea always in mind to avoid conflicts with roadway items, and with signing and lighting if they are included in the project. Each signal post location shall be staked and carefully checked to see that signal heads to be mounted thereon will be in clear view from the lane, or lanes, to be controlled. Posts should not be located in sidewalks if it can be avoided without reducing visibility of signal heads. Pullbox, conduit runs, and controller base locations may have to be shifted to avoid conflict with other items. Care should be taken to avoid placing signal appurtances in a drainage ditch. If necessary, shift the controller base to a location where chances of its being struck by a vehicle are reduced to a minimum. If the controller base is so situated that it cannot be moved refer to [~~http~~://epg.modot.org/index.php/902.15_Designing_a_Traffic_Signal#902.15.2.2_Location_of_Controllers EPG 902.15.2.2] for countermeasure expectations.		Staking and layout work for a traffic signal project should be done with the idea always in mind to avoid conflicts with roadway items, and with signing and lighting if they are included in the project. Each signal post location shall be staked and carefully checked to see that signal heads to be mounted thereon will be in clear view from the lane, or lanes, to be controlled. Posts should not be located in sidewalks if it can be avoided without reducing visibility of signal heads. Pullbox, conduit runs, and controller base locations may have to be shifted to avoid conflict with other items. Care should be taken to avoid placing signal appurtances in a drainage ditch. If necessary, shift the controller base to a location where chances of its being struck by a vehicle are reduced to a minimum. If the controller base is so situated that it cannot be moved refer to [https://epg.modot.org/index.php/902.15_Designing_a_Traffic_Signal#902.15.2.2_Location_of_Controllers EPG 902.15.2.2] for countermeasure expectations.

	==[[902.12 Glossary\|Glossary]]==		==[[902.12 Glossary\|Glossary]]==

Smithk: /* Controller Installation */ Inclusive language

2021-06-04T13:32:18Z

Controller Installation: Inclusive language

← Older revision		Revision as of 08:32, 4 June 2021
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	:(7) Final checking of the entire system.		:(7) Final checking of the entire system.

	During these phases of work the inspector should check tagging of cables for specification compliance. All signal head cables should be terminated on a terminal strip located at the bottom of the control cabinet. Every terminal connection should be checked to see that conductors are held firmly in place. Conductors leaving the conduit should be bunched and laced up neatly before they are fanned out to terminal strips. It is the contractor’s responsibility to make proper terminal connections. The contractor is to check each conductor to determine if it is connected to the proper terminal before the system is placed in operation. The inspector should become familiar with the various circuit diagrams to gain a better understanding of the work involved. After ~~the contractor has~~ finished ~~his~~ conductor terminations the inspector shall require incoming conduit or conduits to be sealed in accordance with Sec 902.15.2.		During these phases of work the inspector should check tagging of cables for specification compliance. All signal head cables should be terminated on a terminal strip located at the bottom of the control cabinet. Every terminal connection should be checked to see that conductors are held firmly in place. Conductors leaving the conduit should be bunched and laced up neatly before they are fanned out to terminal strips. It is the contractor’s responsibility to make proper terminal connections. The contractor is to check each conductor to determine if it is connected to the proper terminal before the system is placed in operation. The inspector should become familiar with the various circuit diagrams to gain a better understanding of the work involved. After contractors have finished their conductor terminations, the inspector shall require incoming conduit or conduits to be sealed in accordance with Sec 902.15.2.

	The inspector should check that all housing vents are free of obstructions and properly screened. If a ventilating fan is specified, the inspector should ascertain that it operates when the cabinet temperature reaches approximately 90 degrees F.		The inspector should check that all housing vents are free of obstructions and properly screened. If a ventilating fan is specified, the inspector should ascertain that it operates when the cabinet temperature reaches approximately 90 degrees F.

Smithk: Per TS, minor clarifications

2020-08-26T20:15:43Z

Per TS, minor clarifications

← Older revision		Revision as of 15:15, 26 August 2020
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	==Staking==		==Staking==
	Staking and layout work for a traffic signal project should be done with the idea always in mind to avoid conflicts with roadway items, and with signing and lighting if they are included in the project. Each signal post location shall be staked and carefully checked to see that signal heads to be mounted thereon will be in clear view from the lane, or lanes, to be controlled. Posts should not be located in sidewalks if it can be avoided without reducing visibility of signal heads. Pullbox, conduit runs, and controller base locations may have to be shifted to avoid conflict with other items. Care should be taken to avoid placing signal appurtances in a drainage ditch. If necessary, shift the controller base to a location where chances of its being struck by a vehicle are reduced to a minimum. If the controller base is so situated that it cannot be moved ~~it may be necessary~~ to ~~place a section or more of guardrail around the controller to provide adequate protection~~.		Staking and layout work for a traffic signal project should be done with the idea always in mind to avoid conflicts with roadway items, and with signing and lighting if they are included in the project. Each signal post location shall be staked and carefully checked to see that signal heads to be mounted thereon will be in clear view from the lane, or lanes, to be controlled. Posts should not be located in sidewalks if it can be avoided without reducing visibility of signal heads. Pullbox, conduit runs, and controller base locations may have to be shifted to avoid conflict with other items. Care should be taken to avoid placing signal appurtances in a drainage ditch. If necessary, shift the controller base to a location where chances of its being struck by a vehicle are reduced to a minimum. If the controller base is so situated that it cannot be moved refer to [http://epg.modot.org/index.php/902.15_Designing_a_Traffic_Signal#902.15.2.2_Location_of_Controllers EPG 902.15.2.2] for countermeasure expectations.

	==[[902.12 Glossary\|Glossary]]==		==[[902.12 Glossary\|Glossary]]==
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	Detector operation should be checked before turning on signal indications. Detector settings should be adjusted for proper coverage so vehicles passing through the detector will cause positive action at the controller.		Detector operation should be checked before turning on signal indications. Detector settings should be adjusted for proper coverage so vehicles passing through the detector will cause positive action at the controller.

	When the inspector is sure the controller, detectors and auxiliary equipment are operating properly and timing is approximately correct, the inspector will have the contractor turn on the signal indications. It is best to watch for a gap in traffic volume to switch the signals on. The inspector checks all signal indications to see that they are displayed in sequence and are aimed properly to direct traffic. During this time the inspector watches traffic movements to see whether the controller is timing movements so there is minimum congestion.		When the inspector is sure the controller, detectors and auxiliary equipment are operating properly and timing is approximately correct, the inspector will have the contractor turn on the signal indications. It is best to watch for a gap in traffic volume to switch the signals on. The inspector checks all signal indications to see that they are displayed in sequence and are aimed properly to direct traffic. During this time the inspector watches traffic movements to see whether the controller is timing movements so there is minimum congestion. If necessary, the inspector can coordinate with a traffic engineer or electrician for assistance.


	[[Category:902 Signals]]		[[Category:902 Signals]]

Smithk: Per CM and TS, new guidance to provide more detail on the intent of Sec 902.2 to help ensure consistent administration of contract signal work

2020-07-10T15:27:20Z

Per CM and TS, new guidance to provide more detail on the intent of Sec 902.2 to help ensure consistent administration of contract signal work

← Older revision		Revision as of 10:27, 10 July 2020
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	[[image:902.13.1.1.jpg\|right\|450px\|thumb\|<center>'''Slot Cutting as discussed in Sec 902.13.2'''</center>]]		[[image:902.13.1.1.jpg\|right\|450px\|thumb\|<center>'''Slot Cutting as discussed in Sec 902.13.2'''</center>]]

	==General ([~~http~~://www.modot.org/~~business/standards_and_specs/SpecbookEPG.pdf#page=13~~ Sec 902.2])==		==General ([https://www.modot.org/missouri-standard-specifications-highway-construction Sec 902.2])==

	Installation of traffic signals can be considered, for the most part, as erecting, installing, and wiring of specialized equipment to control flow of vehicular and pedestrian traffic. Types of control equipment currently specified vary greatly in their makeup and in necessary associated equipment. The type of control equipment specified for a particular project is based on geometrics of the intersection, anticipated volume of traffic that will use the facility, and proximity of other intersections.		Installation of traffic signals can be considered, for the most part, as erecting, installing, and wiring of specialized equipment to control flow of vehicular and pedestrian traffic. Types of control equipment currently specified vary greatly in their makeup and in necessary associated equipment. The type of control equipment specified for a particular project is based on geometrics of the intersection, anticipated volume of traffic that will use the facility, and proximity of other intersections.
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	The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://sp/sites/ts/Pages/default.aspx Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.		The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://sp/sites/ts/Pages/default.aspx Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.

	The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [~~http~~://www.modot.org/~~business/standards_and_specs/SpecbookEPG.pdf#page=13~~ Sec 901.2].		The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [https://www.modot.org/missouri-standard-specifications-highway-construction Sec 901.2].

	In the event that some questions arise about manufacturer's terminology, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.		In the event that some questions arise about manufacturer's terminology, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.

			==Signal Maintenance==
			[https://www.modot.org/missouri-standard-specifications-highway-construction Sec 902.2] requires contractor maintenance of existing signals to begin after any modifications have been made or after work has begun on an existing signal installation. The Resident Engineer should include “maintenance of existing signals” as a discussion item in the pre-construction conference so there is a clear understanding as to when maintenance responsibility will be transferred from MoDOT to the contractor. The contractor’s proposed schedule of operations should be considered when making this determination. Any work activity that affects the function of the existing intersection should be considered the trigger for the shift in maintenance responsibility. This is usually identified as the point when the contractor opens the existing controller cabinet to begin making alterations, but could be earlier, such as when detectors are accidently taken out of service by contractor operations. Once contractor maintenance begins, it continues until the existing signal is removed, or the upgrade is complete, and the new or upgraded signal has successfully completed the 15-day test period.

	==Staking==		==Staking==
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	==Power Supply Assembly (for Sec 902.9)==		==Power Supply Assembly (for Sec 902.9)==
	Refer to [~~http~~://www.modot.org/~~business/standards_and_specs/SpecbookEPG.pdf#page=13~~ Sec 901].		Refer to [https://www.modot.org/missouri-standard-specifications-highway-construction Sec 901].

	===Service Pole Installation (for Sec 902.9.1)===		===Service Pole Installation (for Sec 902.9.1)===
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	==Pull and Junction Boxes (for Sec 902.14)==		==Pull and Junction Boxes (for Sec 902.14)==
	The inspection of excavating, forming and placing concrete for pullboxes or aprons should be done in a manner similar to that set out in [~~http~~://www.modot.org/~~business/standards_and_specs/SpecbookEPG.pdf#page=13~~ Secs 902.14 and 902.20]. Early attention should be given to establishing the proper final grade for all pull boxes. The inspector must also make certain that conduit openings are properly installed in the sides of the pull box. Conduits turned up into the bottom of a pull box should not be allowed.		The inspection of excavating, forming and placing concrete for pullboxes or aprons should be done in a manner similar to that set out in [https://www.modot.org/missouri-standard-specifications-highway-construction Secs 902.14 and 902.20]. Early attention should be given to establishing the proper final grade for all pull boxes. The inspector must also make certain that conduit openings are properly installed in the sides of the pull box. Conduits turned up into the bottom of a pull box should not be allowed.

	It is important to ensure that pull boxes drain properly. The standard drawing depicts two types of pull box drains. If a Type I drain is used, ensure that the proper depth of stone is used. If it becomes evident that, due to the nature of soil or due to the elevation, a particular pull box will not drain properly, it may become necessary to provide a conduit drain in lieu of the stone drain provided on plans. During finish work all cabling should be neatly tied to the cable hooks provided in the pull box.		It is important to ensure that pull boxes drain properly. The standard drawing depicts two types of pull box drains. If a Type I drain is used, ensure that the proper depth of stone is used. If it becomes evident that, due to the nature of soil or due to the elevation, a particular pull box will not drain properly, it may become necessary to provide a conduit drain in lieu of the stone drain provided on plans. During finish work all cabling should be neatly tied to the cable hooks provided in the pull box.

Smithk: updated link

2019-06-05T19:25:32Z

updated link

← Older revision		Revision as of 14:25, 5 June 2019
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	Regardless of the type of control equipment specified or geometrics of the intersection involved, construction procedure is approximately the same for all signal projects. The order of work consists of: (a) laying or pushing conduit network; (b) excavating, forming, and placing of pullboxes, post bases, and controller bases; (c) erection of signal posts; (d) installation of electrical service; (e) installing signal heads; (f) installing detectors; (g) pulling cable into conduits; (h) tagging and wiring signal heads, detectors, interconnection system, and controller; (i) checkout of individual components and final checkout of the entire system. It is the intent of this article to set out inspection procedures in the same general order as work is usually done.		Regardless of the type of control equipment specified or geometrics of the intersection involved, construction procedure is approximately the same for all signal projects. The order of work consists of: (a) laying or pushing conduit network; (b) excavating, forming, and placing of pullboxes, post bases, and controller bases; (c) erection of signal posts; (d) installation of electrical service; (e) installing signal heads; (f) installing detectors; (g) pulling cable into conduits; (h) tagging and wiring signal heads, detectors, interconnection system, and controller; (i) checkout of individual components and final checkout of the entire system. It is the intent of this article to set out inspection procedures in the same general order as work is usually done.
	[[image:902.13 post bases.jpg\|right\|275px\|thumb\|<center>'''Type A and Type B post bases'''</center>]]		[[image:902.13 post bases.jpg\|right\|275px\|thumb\|<center>'''Type A and Type B post bases'''</center>]]
	The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://~~wwwi~~/~~intranet~~/tr/ Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.		The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://sp/sites/ts/Pages/default.aspx Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.

	The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Sec 901.2].		The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Sec 901.2].

Smithk: updated broken std. plan link

2019-05-02T13:00:53Z

updated broken std. plan link

← Older revision		Revision as of 08:00, 2 May 2019
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	The inspection of concrete bases should ensure that conduits are capped, and that ground rods and anchor bolts stay in proper position during concrete placement. Adequate vibration of the concrete is necessary to fill all voids. The contractor is required to protect anchor bolt threads during concrete placement. All concrete should be removed from any signal equipment including threads immediately after finishing has been completed.		The inspection of concrete bases should ensure that conduits are capped, and that ground rods and anchor bolts stay in proper position during concrete placement. Adequate vibration of the concrete is necessary to fill all voids. The contractor is required to protect anchor bolt threads during concrete placement. All concrete should be removed from any signal equipment including threads immediately after finishing has been completed.

	Additional information regarding the inspection of post bases and controller bases can be found in Secs 902.15.1 and 902.15.2 and [~~http~~://www.modot.~~mo.gov/business/standards_and_specs~~/~~documents~~/~~90230.pdf~~ Standard Plan 902.30].		Additional information regarding the inspection of post bases and controller bases can be found in Secs 902.15.1 and 902.15.2 and [https://www.modot.org/media/16914 Standard Plan 902.30].

	==Conduit Systems (for Sec 902.16)==		==Conduit Systems (for Sec 902.16)==

Smithk: updated links

2016-06-15T14:59:16Z

updated links

← Older revision		Revision as of 09:59, 15 June 2016
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	[[image:902.13.1.1.jpg\|right\|450px\|thumb\|<center>'''Slot Cutting as discussed in Sec 902.13.2'''</center>]]		[[image:902.13.1.1.jpg\|right\|450px\|thumb\|<center>'''Slot Cutting as discussed in Sec 902.13.2'''</center>]]

	==General ([http://www.modot.~~mo.gov~~/business/standards_and_specs/~~Sec0902~~.pdf Sec 902.2])==		==General ([http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Sec 902.2])==

	Installation of traffic signals can be considered, for the most part, as erecting, installing, and wiring of specialized equipment to control flow of vehicular and pedestrian traffic. Types of control equipment currently specified vary greatly in their makeup and in necessary associated equipment. The type of control equipment specified for a particular project is based on geometrics of the intersection, anticipated volume of traffic that will use the facility, and proximity of other intersections.		Installation of traffic signals can be considered, for the most part, as erecting, installing, and wiring of specialized equipment to control flow of vehicular and pedestrian traffic. Types of control equipment currently specified vary greatly in their makeup and in necessary associated equipment. The type of control equipment specified for a particular project is based on geometrics of the intersection, anticipated volume of traffic that will use the facility, and proximity of other intersections.
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	The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://wwwi/intranet/tr/ Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.		The inspector assigned to a signal project should thoroughly study the contract. If the inspector has had no previous signal work, they can gain much by study of a previously completed installation. Discussions with [http://wwwi/intranet/tr/ Traffic] are very helpful. They can explain the various types of equipment to be used and give the inspector a better understanding of nomenclature used in signal work.

	The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [http://www.modot.~~mo.gov~~/business/standards_and_specs/~~Sec0901~~.pdf Sec 901.2].		The list of equipment and material that the contractor submits for approval serves the same general purpose as does the list for highway lighting. See [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Sec 901.2].

	In the event that some questions arise about manufacturer's terminology, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.		In the event that some questions arise about manufacturer's terminology, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.
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	==Power Supply Assembly (for Sec 902.9)==		==Power Supply Assembly (for Sec 902.9)==
	Refer to [http://www.modot.~~mo.gov~~/business/standards_and_specs/~~Sec0901~~.pdf Sec 901].		Refer to [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Sec 901].

	===Service Pole Installation (for Sec 902.9.1)===		===Service Pole Installation (for Sec 902.9.1)===
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	==Pull and Junction Boxes (for Sec 902.14)==		==Pull and Junction Boxes (for Sec 902.14)==
	The inspection of excavating, forming and placing concrete for pullboxes or aprons should be done in a manner similar to that set out in [http://www.modot.~~mo.gov~~/business/standards_and_specs/~~Sec0902~~.pdf Secs 902.14 and 902.20]. Early attention should be given to establishing the proper final grade for all pull boxes. The inspector must also make certain that conduit openings are properly installed in the sides of the pull box. Conduits turned up into the bottom of a pull box should not be allowed.		The inspection of excavating, forming and placing concrete for pullboxes or aprons should be done in a manner similar to that set out in [http://www.modot.org/business/standards_and_specs/SpecbookEPG.pdf#page=13 Secs 902.14 and 902.20]. Early attention should be given to establishing the proper final grade for all pull boxes. The inspector must also make certain that conduit openings are properly installed in the sides of the pull box. Conduits turned up into the bottom of a pull box should not be allowed.

	It is important to ensure that pull boxes drain properly. The standard drawing depicts two types of pull box drains. If a Type I drain is used, ensure that the proper depth of stone is used. If it becomes evident that, due to the nature of soil or due to the elevation, a particular pull box will not drain properly, it may become necessary to provide a conduit drain in lieu of the stone drain provided on plans. During finish work all cabling should be neatly tied to the cable hooks provided in the pull box.		It is important to ensure that pull boxes drain properly. The standard drawing depicts two types of pull box drains. If a Type I drain is used, ensure that the proper depth of stone is used. If it becomes evident that, due to the nature of soil or due to the elevation, a particular pull box will not drain properly, it may become necessary to provide a conduit drain in lieu of the stone drain provided on plans. During finish work all cabling should be neatly tied to the cable hooks provided in the pull box.

Smithk: /* Installation Of Posts And Signal Heads (for Sec 902.5) */Per Traffic, reference to aluminum housings was removed to comply with Sec 1092.1.1 (which requires polycarbonate housing)

2012-03-13T12:33:05Z

Installation Of Posts And Signal Heads (for Sec 902.5): Per Traffic, reference to aluminum housings was removed to comply with Sec 1092.1.1 (which requires polycarbonate housing)

← Older revision		Revision as of 07:33, 13 March 2012
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	In the event that some questions arise, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.		In the event that some questions arise, the district traffic personnel will be able to clarify any questions. Terminology will vary slightly from manufacturer to manufacturer but the general concept remains the same.

	==Installation Of Posts ~~And~~ Signal Heads (for Sec 902.5)==		==Installation of Posts and Signal Heads (for Sec 902.5)==
	Before erection of posts and hanging of signal heads, the inspector is to check equipment for shipment damage. The inspector is to also check the numbers of the various items to see that they agree with the numbers on the previously approved list. Inspect posts for plan dimension and signal faces for plan diameter and the arrow and pedestrian lens for compliance with standard drawings. Check for correct clearances of Types C, CL, BL and B signal posts from overhead power lines.		Before erection of posts and hanging of signal heads, the inspector is to check equipment for shipment damage. The inspector is to also check the numbers of the various items to see that they agree with the numbers on the previously approved list. Inspect posts for plan dimension and signal faces for plan diameter and the arrow and pedestrian lens for compliance with standard drawings. Check for correct clearances of Types C, CL, BL and B signal posts from overhead power lines.
	{\|align="right"		{\|align="right"
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	After signal heads have been wired and power is supplied to the controller cabinet, signal faces should be aimed. All signal indications should be verified by applying momentary power to each field wire termination at this time. An optically programmable signal head is sometimes used when it is necessary to limit the visibility zone to specific lanes and areas. Manufacturer’s instructions for installation will provide enough data for an inspector to check this type of signal head properly.		After signal heads have been wired and power is supplied to the controller cabinet, signal faces should be aimed. All signal indications should be verified by applying momentary power to each field wire termination at this time. An optically programmable signal head is sometimes used when it is necessary to limit the visibility zone to specific lanes and areas. Manufacturer’s instructions for installation will provide enough data for an inspector to check this type of signal head properly.

	The current specifications allow the contractor to utilize ~~either die cast aluminum~~ signal housings ~~or those~~ made of polycarbonate material. ~~Since polycarbonate~~ housings are less costly and lighter in weight~~, most contractors are providing the plastic housings, visors, and back plates~~. The inspector is to check all connections, both electrical and mechanical, to ensure all are tightened securely.		The current specifications only allow the contractor to utilize signal housings made of polycarbonate material. Polycarbonate housings are less costly and lighter in weight. The inspector is to check all connections, both electrical and mechanical, to ensure all are tightened securely.

	==Power Supply Assembly (for Sec 902.9)==		==Power Supply Assembly (for Sec 902.9)==