902.23 Traffic Signal Phasing and Operation - Revision history

Hoskir: /* 902.23.7.2 Yellow Change and Red Clearance Intervals */ updated per RR4246

2026-07-22T13:36:06Z

902.23.7.2 Yellow Change and Red Clearance Intervals: updated per RR4246

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	===902.23.7.2 Yellow Change and Red Clearance Intervals===		===902.23.7.2 Yellow Change and Red Clearance Intervals===
			'''Standard.''' A steady yellow signal indication shall be displayed following every CIRCULAR GREEN or GREEN ARROW signal indication and following every flashing YELLOW ARROW signal indication displayed as a part of a steady mode operation. This requirement shall not apply when a CIRCULAR GREEN or a flashing YELLOW ARROW signal indication is followed immediately by a GREEN ARROW signal indication.

	~~'''Standard.''' A steady~~ yellow ~~signal indication~~ shall be ~~displayed following every CIRCULAR GREEN or GREEN ARROW signal indication and following every flashing YELLOW ARROW signal indication displayed as a part~~ of ~~a steady mode operation. This requirement shall not apply when a CIRCULAR GREEN or a flashing YELLOW ARROW signal indication is followed immediately by a GREEN ARROW signal indication~~.		The exclusive function of the yellow change interval shall be to warn traffic of an impending change in the right of way assignment.

	The ~~exclusive function of the~~ yellow change interval ~~shall be~~ to ~~warn traffic~~ of ~~an impending change in the~~ right of way ~~assignment~~.		'''Support.''' The yellow change interval and the red clearance interval (all indications displaying red) are required to prepare the intersection for the transfer of right of way. These intervals permit vehicles that are either within the intersection or so close to it that they cannot comfortably stop to clear the intersection, and to permit those vehicles that can come to a comfortable stop to do so.

	'''Support.''' The yellow change interval and the red clearance interval (all indications displaying red) are required to prepare the intersection for the transfer of right of way. These intervals permit vehicles that are either within the intersection or so close to it that they cannot comfortably stop to clear the intersection, and to permit those vehicles that can come to a comfortable stop to do so.
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	'''Standard.''' The total time for the yellow change interval and the red clearance interval is the change period. All change periods shall be updated using the criteria below.		'''Standard.''' The total time for the yellow change interval and the red clearance interval is the change period. All change periods shall be updated using the criteria below.

	'''Support.''' To determine the appropriate yellow change interval and red clearance interval, ITE has developed a Kinematic Model – Formula shown below. The duration of change and clearance intervals, as well as the appropriateness of red clearance intervals, is a topic with no clear consensus. The following formula is developed based on a kinematic model of stopping behavior to determine the duration of the yellow and red indications and is in common use throughout the country.		'''Support.''' To determine the appropriate yellow change interval and red clearance interval, ITE has developed a Kinematic Model – Formula shown below. The duration of change and clearance intervals, as well as the appropriateness of red clearance intervals, is a topic with no clear consensus. The following formula is developed based on a kinematic model of stopping behavior to determine the duration of the yellow and red indications and is in common use throughout the country.

	Change Period:		Change Period:
			:<math>CP = t + \frac{V}{2a + 64.4g} + \frac{W + L}{V}</math>
	::<math>CP = t + \frac{V}{2a + 64.4g} + \frac{W + L}{V}</math>

	Guidance:		Guidance:
	:CP = nondilemma change period (yellow plus all red), seconds		:CP = nondilemma change period (yellow plus all red), seconds

	:t = perception-reaction time, recommended as 1.0 second		:t = perception-reaction time, recommended as 1.0 second

	:V = approach speed (recommended as 85<sup>th</sup> or 15<sup>th</sup> percentile speed), ft/sec		:V = approach speed (recommended as 85<sup>th</sup> or 15<sup>th</sup> percentile speed), ft/sec

	:g = percent grade (positive for upgrade, negative for downgrade), expressed as a decimal		:g = percent grade (positive for upgrade, negative for downgrade), expressed as a decimal

	:a = deceleration rate, recommended as 10 ft/sec<sup>2</sup>		:a = deceleration rate, recommended as 10 ft/sec<sup>2</sup>

	:W = width of intersection from stop line to end of far side crosswalk (if present), ft.		:W = width of intersection from stop line to end of far side crosswalk (if present), ft.

	:L = length of vehicle, recommended as 20 ft.		:L = length of vehicle, recommended as 20 ft.

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	The sum of the first two terms in the formula is the yellow change interval and the red clearance interval is the last term. The purpose of the yellow change interval is to warn approaching traffic of the imminent change in the assignment of right of way. The first two terms include a reaction time, a deceleration element and approach speed, which are all necessary to determine a yellow change interval that will either allow the driver to come to a stop or proceed through the intersection. The red clearance interval is used to provide additional time following the yellow change interval before conflicting traffic is released. The last term in the formula includes the intersection width, length of vehicle and approach speed, which are all necessary in determining the intersection clearing time.		The sum of the first two terms in the formula is the yellow change interval and the red clearance interval is the last term. The purpose of the yellow change interval is to warn approaching traffic of the imminent change in the assignment of right of way. The first two terms include a reaction time, a deceleration element and approach speed, which are all necessary to determine a yellow change interval that will either allow the driver to come to a stop or proceed through the intersection. The red clearance interval is used to provide additional time following the yellow change interval before conflicting traffic is released. The last term in the formula includes the intersection width, length of vehicle and approach speed, which are all necessary in determining the intersection clearing time.

	'''Standard.''' The yellow change interval shall not be less than three seconds.		'''Standard.''' The yellow change interval shall not be less than three seconds.

	'''Guidance.''' The yellow change interval should not exceed six seconds. The red clearance interval should not exceed six seconds.		'''Guidance.''' The yellow change interval should not exceed six seconds. The red clearance interval should not exceed six seconds.

	'''Option.''' Based on engineering judgment, adjustments to the yellow change interval and red clearance interval may be made provided for each interval:		'''Option.''' Based on engineering judgment, adjustments to the yellow change interval and red clearance interval may be made provided for each interval:

	:1) Yellow and all-red are not less than the calculated values using t = 1 second and a = 10 ft/sec<sup>2</sup> AND		:1) Yellow and all-red are not less than the calculated values using t = 1 second and a = 10 ft/sec<sup>2</sup> AND

	:2) Yellow does not go below the appropriate minimum of 3 seconds AND		:2) Yellow does not go below the appropriate minimum of 3 seconds AND
			:3) Yellow and all-red do not go above their appropriate maximums of 6 seconds OR
	:3) Yellow and all-red do not go above ~~the~~ appropriate ~~maximum~~ of 6 seconds OR

	:4) Special conditions exist (e.g. Single Point Urban Interchange, Continuous Flow Interchange, Dual Lefts, etc.).		:4) Special conditions exist (e.g. Single Point Urban Interchange, Continuous Flow Interchange, Dual Lefts, etc.).

	'''Standard.''' If the conditions are such that the district recommends using values that result in a yellow change interval less than what is calculated by the formula (using the values of t = 1 second and a = 10 ft/sec<sup>2</sup>) and/or a red clearance interval less than what was calculated by using the formula, then a high level of discussion/collaboration with Central Office Traffic Division shall be made.		'''Standard.''' If the conditions are such that the district recommends using values that result in a yellow change interval less than what is calculated by the formula (using the values of t = 1 second and a = 10 ft/sec<sup>2</sup>) and/or a red clearance interval less than what was calculated by using the formula, then a high level of discussion/collaboration with Central Office Traffic Division shall be made.

	'''Support.''' EPG 902.23.11 contains provisions regarding the display of steady CIRCULAR YELLOW signal indications to approaches from which drivers are allowed to make permissive left turns.		'''Support.''' EPG 902.23.11 contains provisions regarding the display of steady CIRCULAR YELLOW signal indications to approaches from which drivers are allowed to make permissive left turns.

Legged1: /* {{SpanID|902.23.5}}902.23.5 Guidelines for Use of the Flashing Yellow Left Arrow (FYA) */ RR4245

2026-07-10T13:00:47Z

{{SpanID|902.23.5}}902.23.5 Guidelines for Use of the Flashing Yellow Left Arrow (FYA): RR4245

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	'''Support.''' Verify the installation of a stacked 4-section head is possible at a location with an existing 5- or 3-section head. If the turn head has a circular green being shared as the 2nd through indication, then a dedicated signal head will be needed for the 2nd through. Check field wiring to ensure there are enough dedicated conductors to drive the new signal heads. More conductors will be needed for a FYA head than a 5-section head, since each indication must be driven from the cabinet and not jumpered off the adjacent through.		'''Support.''' Verify the installation of a stacked 4-section head is possible at a location with an existing 5- or 3-section head. If the turn head has a circular green being shared as the 2nd through indication, then a dedicated signal head will be needed for the 2nd through. Check field wiring to ensure there are enough dedicated conductors to drive the new signal heads. More conductors will be needed for a FYA head than a 5-section head, since each indication must be driven from the cabinet and not jumpered off the adjacent through.

	'''Standard.''' A LEFT TURN YIELD ON FLASHING ARROW (R10-~~27a~~) sign shall be mounted adjacent to the head.		'''Standard.''' A LEFT TURN YIELD ON FLASHING YELLOW ARROW (R10-12a) sign shall be mounted adjacent to the head.

	When a new signal is being built or where an existing signal is being reconstructed, the FYA shall be used for the permissive left turn movement. All new cabinets shall be configured for FYA operation on all left turns.		When a new signal is being built or where an existing signal is being reconstructed, the FYA shall be used for the permissive left turn movement. All new cabinets shall be configured for FYA operation on all left turns.

Hoskir: /* 902.23.1.2 Fully-actuated Control */ updated link

2026-03-02T19:28:57Z

902.23.1.2 Fully-actuated Control: updated link

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	The phases in an actuated controller can be assigned or grouped in many ways to provide unique operations that best serve the intersection's needs. The most common is the dual ring eight-phase configuration. This arrangement allows for separate through and left turn phases for up to four approaches. The opposing left turns are typically on concurrently, either leading or lagging. Through the software, the phases can be repositioned to provide a lead-lag left operation if so desired. Examples of typically used configurations are found in [http://sp/sites/sl/programdelivery/design/SignalsandLighting/Shared%20Documents/Signal_Phasing_and_Layout_Examples.pdf#search=signal%20phasing%20layout Signal Phasing and Layout Examples].		The phases in an actuated controller can be assigned or grouped in many ways to provide unique operations that best serve the intersection's needs. The most common is the dual ring eight-phase configuration. This arrangement allows for separate through and left turn phases for up to four approaches. The opposing left turns are typically on concurrently, either leading or lagging. Through the software, the phases can be repositioned to provide a lead-lag left operation if so desired. Examples of typically used configurations are found in [http://sp/sites/sl/programdelivery/design/SignalsandLighting/Shared%20Documents/Signal_Phasing_and_Layout_Examples.pdf#search=signal%20phasing%20layout Signal Phasing and Layout Examples].

	Efficient actuated operation is dependent on the type and placement of the detectors. Poor detector placement can have a serious impact on the delay and capacity of an intersection. Different types of detection are discussed in [[902.21_Designing_a_MoDOT_Traffic_Signal#902.21.7_Detectors\|EPG 902.21.7]] and [[902.26_Construction_Inspection_Guidelines_for_Sec_902#Detector_Installation_(for_Sec_902.13)\|EPG 902.26 - Detector Installation (for Sec 902.13)]]. Typically, stop bar presence detection is used. A common presence detector is a 6 ft. x 30 ft. area. Mainline through detection can be supplemented with advanced detectors located a distance from the stop bar based on the speed of approaching traffic.		Efficient actuated operation is dependent on the type and placement of the detectors. Poor detector placement can have a serious impact on the delay and capacity of an intersection. Different types of detection are discussed in [[902.21_Designing_a_MoDOT_Traffic_Signal#902.21.7_Detectors\|EPG 902.21.7 Detectors]] and [[902.26_Construction_Inspection_Guidelines_for_Sec_902#Detector_Installation_(for_Sec_902.13)\|EPG 902.26 - Detector Installation (for Sec 902.13)]]. Typically, stop bar presence detection is used. A common presence detector is a 6 ft. x 30 ft. area. Mainline through detection can be supplemented with advanced detectors located a distance from the stop bar based on the speed of approaching traffic.

	Full actuation and advance vehicle detection on high-speed approaches are typically used to reduce the frequency of vehicles in the “dilemma zone”. The dilemma zone is the area where the onset of the yellow change interval creates difficulty for the driver to decide whether to stop or proceed.		Full actuation and advance vehicle detection on high-speed approaches are typically used to reduce the frequency of vehicles in the “dilemma zone”. The dilemma zone is the area where the onset of the yellow change interval creates difficulty for the driver to decide whether to stop or proceed.

Hoskir: /* 902.23.1.2 Fully-actuated Control */ updated links

2026-02-23T14:51:04Z

902.23.1.2 Fully-actuated Control: updated links

← Older revision		Revision as of 09:51, 23 February 2026
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	The phases in an actuated controller can be assigned or grouped in many ways to provide unique operations that best serve the intersection's needs. The most common is the dual ring eight-phase configuration. This arrangement allows for separate through and left turn phases for up to four approaches. The opposing left turns are typically on concurrently, either leading or lagging. Through the software, the phases can be repositioned to provide a lead-lag left operation if so desired. Examples of typically used configurations are found in [http://sp/sites/sl/programdelivery/design/SignalsandLighting/Shared%20Documents/Signal_Phasing_and_Layout_Examples.pdf#search=signal%20phasing%20layout Signal Phasing and Layout Examples].		The phases in an actuated controller can be assigned or grouped in many ways to provide unique operations that best serve the intersection's needs. The most common is the dual ring eight-phase configuration. This arrangement allows for separate through and left turn phases for up to four approaches. The opposing left turns are typically on concurrently, either leading or lagging. Through the software, the phases can be repositioned to provide a lead-lag left operation if so desired. Examples of typically used configurations are found in [http://sp/sites/sl/programdelivery/design/SignalsandLighting/Shared%20Documents/Signal_Phasing_and_Layout_Examples.pdf#search=signal%20phasing%20layout Signal Phasing and Layout Examples].

	Efficient actuated operation is dependent on the type and placement of the detectors. Poor detector placement can have a serious impact on the delay and capacity of an intersection. Different types of detection are discussed in [[#902.5.~~7 Detectors~~\|EPG 902.5.7]] and [[902.~~15 Designing a Traffic Signal~~#~~902~~.~~15.3 Detectors~~\|EPG 902.15.3]]. Typically, stop bar presence detection is used. A common presence detector is a 6 ft. x 30 ft. area. Mainline through detection can be supplemented with advanced detectors located a distance from the stop bar based on the speed of approaching traffic.		Efficient actuated operation is dependent on the type and placement of the detectors. Poor detector placement can have a serious impact on the delay and capacity of an intersection. Different types of detection are discussed in [[902.21_Designing_a_MoDOT_Traffic_Signal#902.21.7_Detectors\|EPG 902.21.7]] and [[902.26_Construction_Inspection_Guidelines_for_Sec_902#Detector_Installation_(for_Sec_902.13)\|EPG 902.26 - Detector Installation (for Sec 902.13)]]. Typically, stop bar presence detection is used. A common presence detector is a 6 ft. x 30 ft. area. Mainline through detection can be supplemented with advanced detectors located a distance from the stop bar based on the speed of approaching traffic.

	Full actuation and advance vehicle detection on high-speed approaches are typically used to reduce the frequency of vehicles in the “dilemma zone”. The dilemma zone is the area where the onset of the yellow change interval creates difficulty for the driver to decide whether to stop or proceed.		Full actuation and advance vehicle detection on high-speed approaches are typically used to reduce the frequency of vehicles in the “dilemma zone”. The dilemma zone is the area where the onset of the yellow change interval creates difficulty for the driver to decide whether to stop or proceed.

Hoskir: /* 902.23.3.4 Alternate Sequences */ removed link not needed

2026-02-23T14:47:38Z

902.23.3.4 Alternate Sequences: removed link not needed

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	===902.23.3.4 Alternate Sequences===		===902.23.3.4 Alternate Sequences===

	'''Support.''' When needed, the normal NEMA ring sequence can be altered to fit operating conditions, with restrictions as detailed in ~~[[#902.23.3 Signal Phasing\|~~EPG 902.23.3]]. The most common application is to provide lead-lag left turns. Assume this phasing assignment for the following intersection:		'''Support.''' When needed, the normal NEMA ring sequence can be altered to fit operating conditions, with restrictions as detailed in EPG 902.23.3. The most common application is to provide lead-lag left turns. Assume this phasing assignment for the following intersection:

	[[File:Alternate Sequence.gif\|frame\|center\|<center>'''Alternate Sequence'''</center>]]		[[File:Alternate Sequence.gif\|frame\|center\|<center>'''Alternate Sequence'''</center>]]

Hoskir: /* 902.23.7.1.2 Maximum Green */ updated link

2026-02-23T14:44:35Z

902.23.7.1.2 Maximum Green: updated link

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	'''Support.''' Controllers allow for different maximum settings to be enacted through the time clock. This is useful if heavy demand on a certain phase can be accurately predicted and set to a time of day. This is also useful with semi-actuated control where the mainline timing is controlled by a maximum recall since mainline demand typically changes by time of day. Controller clocks should be set by a central signal system if utilized; however, if there is not a central signal system it is recommended to set the controller clock using www.time.gov to remain consistent.		'''Support.''' Controllers allow for different maximum settings to be enacted through the time clock. This is useful if heavy demand on a certain phase can be accurately predicted and set to a time of day. This is also useful with semi-actuated control where the mainline timing is controlled by a maximum recall since mainline demand typically changes by time of day. Controller clocks should be set by a central signal system if utilized; however, if there is not a central signal system it is recommended to set the controller clock using www.time.gov to remain consistent.

	'''Guidance.''' Although the concept of a cycle length is usually reserved for pre-timed control and coordinated actuated control, it can be applied to isolated, actuated control. The temptation to set all maximums at an isolated intersection extremely high should be avoided. Maximum settings too high result in longer delay for other approaches and defeat the flexibility of actuated control by creating needless backups. See [[#902.23.~~5 Coordination~~\|EPG 902.23.5 Coordination]] for more discussion on cycle lengths for all types of control.		'''Guidance.''' Although the concept of a cycle length is usually reserved for pre-timed control and coordinated actuated control, it can be applied to isolated, actuated control. The temptation to set all maximums at an isolated intersection extremely high should be avoided. Maximum settings too high result in longer delay for other approaches and defeat the flexibility of actuated control by creating needless backups. See [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.11_Coordination\|EPG 902.23.11 Coordination]] for more discussion on cycle lengths for all types of control.

	===902.23.7.2 Yellow Change and Red Clearance Intervals===		===902.23.7.2 Yellow Change and Red Clearance Intervals===

Hoskir: /* 902.23.12 Controller Assembly Components */ updated link

2026-02-23T14:42:32Z

902.23.12 Controller Assembly Components: updated link

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	===902.23.12.1 Controller Unit ===		===902.23.12.1 Controller Unit ===

	'''Support.''' The controller unit (CU) is a solid-state traffic actuated unit. The CU interfaces with a number of low voltage (logic level) input and output functions to control signal lamps, receive inputs from detectors, operate in coordinated systems, etc. Additional information on types of control is found in [[#902.5.~~2 Traffic Signal Operation~~\|EPG 902.5.2 Traffic Signal Operation]].		'''Support.''' The controller unit (CU) is a solid-state traffic actuated unit. The CU interfaces with a number of low voltage (logic level) input and output functions to control signal lamps, receive inputs from detectors, operate in coordinated systems, etc. Additional information on types of control is found in [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.1_Traffic_Signal_Operation\|EPG 902.23.1 Traffic Signal Operation]].

	<u>NEMA TS1</u>		<u>NEMA TS1</u>
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	===902.23.12.5 Detector Interface ===		===902.23.12.5 Detector Interface ===

	'''Support.''' The detector interface provides connections between the CU and the detection devices. In solid-state pre-timed and NEMA TS1 controllers, the connections are made through the back panel. In NEMA TS2 controllers, the detector inputs and outputs are linked to the CU through a BIU. In Type 170/2070 cabinets, the input file serves as the detector interface.		'''Support.''' The detector interface provides connections between the CU and the detection devices. In solid-state pre-timed and NEMA TS1 controllers, the connections are made through the back panel. In NEMA TS2 controllers, the detector inputs and outputs are linked to the CU through a BIU. In Type 170/2070 cabinets, the input file serves as the detector interface.

	=={{SpanID\|902.23.13}}902.23.13 Detectors==		=={{SpanID\|902.23.13}}902.23.13 Detectors==

Hoskir: /* 902.23.11.2.4.2 Phase Sequence */ updated link

2026-02-23T14:40:10Z

902.23.11.2.4.2 Phase Sequence: updated link

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	=====902.23.11.2.4.2 Phase Sequence=====		=====902.23.11.2.4.2 Phase Sequence=====

	'''Guidance.''' When more than two phases are used, the sequence in which the indications are displayed must be determined for each timing plan. The usual choice is when to display a protected left turn in relation to the mainline green: at the start (lead) or the end (lag). The use of lead-lag for protected left turns on the mainline can greatly affect the progression. (See [[#902.5.27.~~1 Leading and Lagging Left~~-Turns\|EPG 902.5.27.1 Leading and Lagging Left-Turns]].)		'''Guidance.''' When more than two phases are used, the sequence in which the indications are displayed must be determined for each timing plan. The usual choice is when to display a protected left turn in relation to the mainline green: at the start (lead) or the end (lag). The use of lead-lag for protected left turns on the mainline can greatly affect the progression. (See [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.3.2_Leading_and_Lagging_Left-Turns\|EPG 902.23.3.2 Leading and Lagging Left-Turns]].)

	If optimization software is being used, the program will generally give a mainline sequence at each intersection that maximizes the green band. Side street sequencing is usually left up to the user. There might be some timing plans where the side street sequence becomes a factor in coordination. A heavy left turn onto the mainline might call for a sequence that puts the side street left turn indications at a point in the cycle that allows for the group to clear a downstream intersection.		If optimization software is being used, the program will generally give a mainline sequence at each intersection that maximizes the green band. Side street sequencing is usually left up to the user. There might be some timing plans where the side street sequence becomes a factor in coordination. A heavy left turn onto the mainline might call for a sequence that puts the side street left turn indications at a point in the cycle that allows for the group to clear a downstream intersection.

	====902.23.11.2.5 Determine Offsets and Transition in Each Timing Plan====		====902.23.11.2.5 Determine Offsets and Transition in Each Timing Plan====

Hoskir: /* {{SpanID|902.23.10}}902.23.10 Control Features for Non-coordinated Signals */

2026-02-23T14:30:55Z

{{SpanID|902.23.10}}902.23.10 Control Features for Non-coordinated Signals

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	:Many actuated controllers also have a feature called “soft recall” that allows the selected phase to be serviced only if there are no other conflicting calls. This feature can be used on the main street during periods of light traffic. The advantage over minimum recall is the controller can skip servicing the main street, if no real calls exist, and move on to the next called phase. This can provide a quicker response during the periods of light traffic.		:Many actuated controllers also have a feature called “soft recall” that allows the selected phase to be serviced only if there are no other conflicting calls. This feature can be used on the main street during periods of light traffic. The advantage over minimum recall is the controller can skip servicing the main street, if no real calls exist, and move on to the next called phase. This can provide a quicker response during the periods of light traffic.

	:For more information about Recall Phases refer to [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8.6_Recalled_Phases\|EPG 902.23.8.6].		:For more information about Recall Phases refer to [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8.6_Recalled_Phases\|EPG 902.23.8.6]].

	=={{SpanID\|902.23.11}}902.23.11 Coordination==		=={{SpanID\|902.23.11}}902.23.11 Coordination==

Hoskir: /* {{SpanID|902.23.10}}902.23.10 Control Features for Non-coordinated Signals */ updated links

2026-02-23T14:30:35Z

{{SpanID|902.23.10}}902.23.10 Control Features for Non-coordinated Signals: updated links

← Older revision		Revision as of 09:30, 23 February 2026
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	:Gap reduction which allows the passage time to decrease as the speed of the flow increases is another setting commonly used at locations with advance detection.		:Gap reduction which allows the passage time to decrease as the speed of the flow increases is another setting commonly used at locations with advance detection.

	:Features of density control are discussed in [[#902.5.37.~~2 Advance Detectors and Gap Reduction~~\|EPG 902.5.37.2]].		:Features of density control are discussed in [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8.2_Advance_Detectors_and_Gap_Reduction\|EPG 902.23.8.2]].

	:'''3. Recall Operation.''' Each phase of a controller is equipped with a recall feature. With recall disabled, the phase responds only to its detectors. With recall enabled, the controller can place a call to service that phase without vehicles being detected. This is accomplished by the controller placing a single call back to the phase when the clearance interval is initiated.		:'''3. Recall Operation.''' Each phase of a controller is equipped with a recall feature. With recall disabled, the phase responds only to its detectors. With recall enabled, the controller can place a call to service that phase without vehicles being detected. This is accomplished by the controller placing a single call back to the phase when the clearance interval is initiated.
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	:Many actuated controllers also have a feature called “soft recall” that allows the selected phase to be serviced only if there are no other conflicting calls. This feature can be used on the main street during periods of light traffic. The advantage over minimum recall is the controller can skip servicing the main street, if no real calls exist, and move on to the next called phase. This can provide a quicker response during the periods of light traffic.		:Many actuated controllers also have a feature called “soft recall” that allows the selected phase to be serviced only if there are no other conflicting calls. This feature can be used on the main street during periods of light traffic. The advantage over minimum recall is the controller can skip servicing the main street, if no real calls exist, and move on to the next called phase. This can provide a quicker response during the periods of light traffic.

	:For more information about Recall Phases refer to [~~https://epg.modot.org/index.php/~~902.~~5_Traffic_Control_Signal_Features_(MUTCD_Chapter_4D)~~#902.5.37.6_Recalled_Phases EPG 902.5.37.6].		:For more information about Recall Phases refer to [[902.23_Traffic_Signal_Phasing_and_Operation#902.23.8.6_Recalled_Phases\|EPG 902.23.8.6].

	=={{SpanID\|902.23.11}}902.23.11 Coordination==		=={{SpanID\|902.23.11}}902.23.11 Coordination==