902.21 Designing a MoDOT Traffic Signal - Revision history

Hoskir: /* 902.21.7.2.3 Detectors for Through Traffic */ updated link

2026-02-23T14:56:33Z

902.21.7.2.3 Detectors for Through Traffic: updated link

← Older revision		Revision as of 09:56, 23 February 2026
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	'''Guidance.''' On approaches with operating speeds of 45 mph or greater, advance detection is to be considered to allow adequate time for a vehicle to pass through the intersection with a green signal indication. An advance detector is located at a distance back from the stop bar determined by the Driver Reaction to Yellow chart. This range of distance from the stop line within which drivers are often indecisive is known as the dilemma zone. To provide dilemma zone protection on high speed approaches, the detector should be placed at least five seconds travel time from the stop line.		'''Guidance.''' On approaches with operating speeds of 45 mph or greater, advance detection is to be considered to allow adequate time for a vehicle to pass through the intersection with a green signal indication. An advance detector is located at a distance back from the stop bar determined by the Driver Reaction to Yellow chart. This range of distance from the stop line within which drivers are often indecisive is known as the dilemma zone. To provide dilemma zone protection on high speed approaches, the detector should be placed at least five seconds travel time from the stop line.

	Refer to [[902.~~5 Traffic Control Signal Features (MUTCD Chapter 4D)~~#902.5.37.~~3 Detection on High~~-~~Speed Approaches~~\|EPG 902.5.37.3 Detection on High-Speed Approaches]] for additional information.		Refer to [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8.3_Detection_on_High-Speed_Approaches\|EPG 902.23.8.3 Detection on High-Speed Approaches]] for additional information.

	===902.21.7.3 Time Delay Unit===		===902.21.7.3 Time Delay Unit===

Hoskir: /* 902.21.7.3 Time Delay Unit */ updated link

2026-02-23T14:53:28Z

902.21.7.3 Time Delay Unit: updated link

← Older revision		Revision as of 09:53, 23 February 2026
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	:* Exclusive left turn lanes where protected-permissive left turn phasing (with a five-section signal head) is used.		:* Exclusive left turn lanes where protected-permissive left turn phasing (with a five-section signal head) is used.

	Time delay detectors can be used in other situations as needed. Refer to [[902.~~5 Traffic Control Signal Features (MUTCD Chapter 4D)~~#902.5.~~37 Detector Settings~~\|EPG 902.5.37 Detector Settings]] for additional information.		Time delay detectors can be used in other situations as needed. Refer to [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8_Detector_Settings\|EPG 902.23.8 Detector Settings]] for additional information.

	===902.21.7.4 Video Detectors===		===902.21.7.4 Video Detectors===

Hoskir: /* 902.21.5.1 Preliminary Layout */ Signal Pasing link updated.

2026-02-23T14:23:00Z

902.21.5.1 Preliminary Layout: Signal Pasing link updated.

← Older revision		Revision as of 09:23, 23 February 2026
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	Signal faces, posts, detectors, and pull boxes are numbered to provide a means of tabulating quantities. A suggested method of numbering is to number the posts and pull boxes first.		Signal faces, posts, detectors, and pull boxes are numbered to provide a means of tabulating quantities. A suggested method of numbering is to number the posts and pull boxes first.

	'''Standard.''' Signal faces and detectors are numbered to reflect the associated signal phase number (see [[902.~~5 Traffic Control Signal Features (MUTCD Chapter 4D)~~#902.5.~~3 Signal Phasing~~\|EPG 902.5.3 Signal Phasing]]). Signal heads located in front of left turn auxiliary lanes are numbered to reflect a separate left turn phase even if the left turn phase is not being used. Pedestrian heads are numbered to reflect the phase they are associated with.		'''Standard.''' Signal faces and detectors are numbered to reflect the associated signal phase number (see [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.2_Signal_Phasing\|EPG 902.23.2 Signal Phasing]]). Signal heads located in front of left turn auxiliary lanes are numbered to reflect a separate left turn phase even if the left turn phase is not being used. Pedestrian heads are numbered to reflect the phase they are associated with.

	'''Guidance.''' The following applicable features should be shown on the preliminary layout:		'''Guidance.''' The following applicable features should be shown on the preliminary layout:

Hoskir: Renamed, renumbered and updated article due to MUTCD updates (See Special Ballot) from 902.15 and added content from 902.4

2026-01-05T18:19:07Z

Renamed, renumbered and updated article due to MUTCD updates (See Special Ballot) from 902.15 and added content from 902.4

Show changes

Hoskir: Hoskir moved page 902.15 Designing a Traffic Signal to 902.21 Designing a MoDOT Traffic Signal: renumbered and renamed due to MUTCD Update (See Special Ballot)

2026-01-05T18:16:39Z

Hoskir moved page 902.15 Designing a Traffic Signal to 902.21 Designing a MoDOT Traffic Signal: renumbered and renamed due to MUTCD Update (See Special Ballot)

← Older revision	Revision as of 13:16, 5 January 2026
(No difference)

Hoskir: /* Table 902.15.6.2.3 Equipment -Power Requirements */ updated alignment

2024-05-28T19:52:31Z

Table 902.15.6.2.3 Equipment -Power Requirements: updated alignment

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	\|}		\|}

	====<center>''Table 902.15.6.2.3 Equipment -Power Requirements''====		====<center>''Table 902.15.6.2.3 Equipment -Power Requirements''</center>====

	~~<center>~~		{\| border="1" class="wikitable" style="margin: 1em auto 1em auto"
	{\| border="1" class="wikitable" style="margin: 1em auto 1em auto~~" style="text-align:center~~"
	\|+		\|+
	!style="background:#BEBEBE"\| !! style="background:#BEBEBE"\|ITEM!!style="background:#BEBEBE" width=90\|WATTS!!style="background:#BEBEBE" width=90\|AMPS		!style="background:#BEBEBE"\| !! style="background:#BEBEBE"\|ITEM!!style="background:#BEBEBE" width=90\|WATTS!!style="background:#BEBEBE" width=90\|AMPS
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	\|\| Cabinet Fan, Outlet and Cabinet Lamp\|\| 240 \|\| align="center"\|2.0		\|\| Cabinet Fan, Outlet and Cabinet Lamp\|\| 240 \|\| align="center"\|2.0
	\|}		\|}
	~~</center>~~

	====<center>''Table 902.15.6.2.4 Circuit Breaker Sizing''</center>====		====<center>''Table 902.15.6.2.4 Circuit Breaker Sizing''</center>====

Hoskir: /* Table 902.15.6.2.3 Equipment -Power Requirements */ updated formatting

2024-05-28T19:40:34Z

Table 902.15.6.2.3 Equipment -Power Requirements: updated formatting

← Older revision		Revision as of 14:40, 28 May 2024
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	====<center>''Table 902.15.6.2.3 Equipment -Power Requirements''====		====<center>''Table 902.15.6.2.3 Equipment -Power Requirements''====

			<center>
	{\| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"		{\| border="1" class="wikitable" style="margin: 1em auto 1em auto" style="text-align:center"
	\|+		\|+

Hoskir: /* 902.15.3.1 Optional Bidding of Traffic Signal Detectors */ updated per RR3876

2024-05-10T14:43:01Z

902.15.3.1 Optional Bidding of Traffic Signal Detectors: updated per RR3876

← Older revision		Revision as of 09:43, 10 May 2024
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	===902.15.3.1 Optional Bidding of Traffic Signal Detectors===		===902.15.3.1 Optional Bidding of Traffic Signal Detectors===

	'''Guidance.''' So that every effort is made to increase the competition for installation of traffic signal detectors on signal projects, contractors should be allowed to bid optional traffic signal detectors. The core team should look at signal detector options or combination of options that bring the best value to the project. While optional bidding is generally advantageous for all projects, circumstances occasionally arise that cause one signal detector type to be preferred over others or the number of alternate detectors to be bid upon for a project are limited. The core team decision, which will include the concurrence of the Design Liaison Engineer, is documented ~~through the Design Exception Process~~.		'''Guidance.''' So that every effort is made to increase the competition for installation of traffic signal detectors on signal projects, contractors should be allowed to bid optional traffic signal detectors. The core team should look at signal detector options or combination of options that bring the best value to the project. While optional bidding is generally advantageous for all projects, circumstances occasionally arise that cause one signal detector type to be preferred over others or the number of alternate detectors to be bid upon for a project are limited. The core team decision, which will include the concurrence of the Design Liaison Engineer, is documented with a memo in eProjects.

	Considerations for not allowing optional bids on signal detectors or limiting the types of signal detectors to be bid upon in a given project need to be evaluated for each intersection within that project. Strengths and weaknesses for each type of signal detector are provided in the table below. Consideration should be given to initial construction cost, long-term maintenance cost and continuity.		Considerations for not allowing optional bids on signal detectors or limiting the types of signal detectors to be bid upon in a given project need to be evaluated for each intersection within that project. Strengths and weaknesses for each type of signal detector are provided in the table below. Consideration should be given to initial construction cost, long-term maintenance cost and continuity.
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	:* Applicable Job Special Provision (OPTIONAL TRAFFIC SIGNAL DETECTORS JSP-07-XX) should be inserted in the Job Special Provisions.		:* Applicable Job Special Provision (OPTIONAL TRAFFIC SIGNAL DETECTORS JSP-07-XX) should be inserted in the Job Special Provisions.

	:* Final plans will be changed to reflect the type of detector chosen.		:* Final plans will be changed to reflect the type of detector chosen.

	===902.15.3.2 Induction Loop Detectors===		===902.15.3.2 Induction Loop Detectors===

Hoskir: /* 902.15.3.1.1 Project Details */ updated JSP link

2023-03-06T13:45:56Z

902.15.3.1.1 Project Details: updated JSP link

← Older revision		Revision as of 08:45, 6 March 2023
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	====902.15.3.1.1 Project Details====		====902.15.3.1.1 Project Details====

	'''Guidance.''' It is likely there will be specific requirements for certain approaches in any project. Section 2.1 of the JSP, Optional Traffic Signal Detectors, should list the details for all detector locations that will not be covered by the chosen option or options. Examples include utilizing existing detection for unaffected approaches, limiting or disqualifying options for back detection, or requiring advanced options (volume, speed, occupancy, etc.) as needed.		'''Guidance.''' It is likely there will be specific requirements for certain approaches in any project. Section 2.1 of the JSP, [https://epg.modot.org/forms/JSP/JSP0709.docx Optional Traffic Signal Detectors], should list the details for all detector locations that will not be covered by the chosen option or options. Examples include utilizing existing detection for unaffected approaches, limiting or disqualifying options for back detection, or requiring advanced options (volume, speed, occupancy, etc.) as needed.

	====902.15.3.1.2 Plans for Projects with Optional Detection====		====902.15.3.1.2 Plans for Projects with Optional Detection====

Hallej1: /* 902.15.7-Traffic Signal Installations */

2022-08-12T13:41:27Z

902.15.7-Traffic Signal Installations

← Older revision		Revision as of 08:41, 12 August 2022
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	After the required area is computed, use Table 902.15.6.2.2 to determine the size wire to be used. If the maximum factored amperage exceeds the maximum load for that wire size as shown in Table 902.15.6.2.2, use the wire size required to carry the load.		After the required area is computed, use Table 902.15.6.2.2 to determine the size wire to be used. If the maximum factored amperage exceeds the maximum load for that wire size as shown in Table 902.15.6.2.2, use the wire size required to carry the load.

	==902.15.7-Traffic Signal Installations==		==902.15.7 Traffic Signal Installations==

	'''Guidance.''' Permanent signals are installations using steel mast arm poles or steel span wire, underground conduit and basic intersection lighting. Temporary signals are installed using wood poles. They are used for construction projects or where a project will be replacing them in the near future. Mast arm pole signal installations are preferable, but each case is decided on its own merits and the funding available. If a street is to be widened or an intersection is to be reconstructed in the near future, the temporary traffic signal installation is designed to conform to the final layout, as nearly as is practical, and if future interconnection can be predicted, the temporary traffic signal controller is equipped for this eventuality.		'''Guidance.''' Permanent signals are installations using steel mast arm poles or steel span wire, underground conduit and basic intersection lighting. Temporary signals are installed using wood poles. They are used for construction projects or where a project will be replacing them in the near future. Mast arm pole signal installations are preferable, but each case is decided on its own merits and the funding available. If a street is to be widened or an intersection is to be reconstructed in the near future, the temporary traffic signal installation is designed to conform to the final layout, as nearly as is practical, and if future interconnection can be predicted, the temporary traffic signal controller is equipped for this eventuality.