234.4 Single Point Urban Interchanges (SPUIs) - Revision history

Hoskir: /* 234.4.1.11 Grading */ changed geopak to OpenRoads Designer

2024-01-16T15:05:21Z

234.4.1.11 Grading: changed geopak to OpenRoads Designer

← Older revision		Revision as of 10:05, 16 January 2024
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	===234.4.1.11 Grading===		===234.4.1.11 Grading===

	MicroStation, ~~GEOPAK~~ or other computer programs or aids are used to compute grading quantities in interchange areas. The method used is dependent upon the type of interchange, the terrain, and other site-specific factors. Regardless of the method, the plans will include adequate cross sections or contours to determine the quantity of grading material within the interchange area.		MicroStation, OpenRoads Designer or other computer programs or aids are used to compute grading quantities in interchange areas. The method used is dependent upon the type of interchange, the terrain, and other site-specific factors. Regardless of the method, the plans will include adequate cross sections or contours to determine the quantity of grading material within the interchange area.

	===234.4.1.12 Site Grading===		===234.4.1.12 Site Grading===

Hallej1 at 15:01, 30 August 2022

2022-08-30T15:01:28Z

← Older revision		Revision as of 10:01, 30 August 2022
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	\|'''Interchange, Single Point'''		\|'''Interchange, Single Point'''
	\|-		\|-
	\|[~~http~~://~~library~~.modot.mo.gov/~~RDT~~/~~reports~~/~~RI02015~~/RDT04011.pdf Report 2004]		\|[ https://spexternal.modot.mo.gov/sites/cm/CORDT/RDT04011.pdf Report 2004]
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	~~\|[http://library.modot.mo.gov/RDT/reports/RI02015/RDT04011.pdf Summary 2005~~]
	\|-		\|-
	\|'''See also:''' [https://www.modot.org/research-publications Research Publications]		\|'''See also:''' [https://www.modot.org/research-publications Research Publications]

Smithk at 20:18, 18 August 2020

2020-08-18T20:18:29Z

← Older revision		Revision as of 15:18, 18 August 2020
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	\|[http://library.modot.mo.gov/RDT/reports/RI02015/RDT04011.pdf Summary 2005]		\|[http://library.modot.mo.gov/RDT/reports/RI02015/RDT04011.pdf Summary 2005]
	\|-		\|-
	\|'''See also:''' [~~http~~://www.modot.~~gov~~/~~services/OR/byDate.htm Innovation Library~~]		\|'''See also:''' [https://www.modot.org/research-publications Research Publications]
	\|}		\|}

Smithk: /* 234.4.1.11 Grading */ Per CADD, deleted CADD links

2019-06-24T15:15:32Z

234.4.1.11 Grading: Per CADD, deleted CADD links

← Older revision		Revision as of 10:15, 24 June 2019
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	===234.4.1.11 Grading===		===234.4.1.11 Grading===

	~~[http://caddnet/index.php?title=Category:~~MicroStation ~~MicroStation]~~, ~~[http://caddnet/index.php?title=Category:GEOPAK_Road~~ GEOPAK] or other computer programs or aids are used to compute grading quantities in interchange areas. The method used is dependent upon the type of interchange, the terrain, and other site-specific factors. Regardless of the method, the plans will include adequate cross sections or contours to determine the quantity of grading material within the interchange area.		MicroStation, GEOPAK or other computer programs or aids are used to compute grading quantities in interchange areas. The method used is dependent upon the type of interchange, the terrain, and other site-specific factors. Regardless of the method, the plans will include adequate cross sections or contours to determine the quantity of grading material within the interchange area.

	===234.4.1.12 Site Grading===		===234.4.1.12 Site Grading===

Smithk: /* 234.4.1.3 Ramp and Preliminary Plan Criteria */

2018-09-28T19:20:42Z

234.4.1.3 Ramp and Preliminary Plan Criteria

← Older revision		Revision as of 14:20, 28 September 2018
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	Ramp base lines are always equated to the survey centerline and other ramp base line intersection points or the crossroad centerline intersection point. The equations include offsets and intersection angles.		Ramp base lines are always equated to the survey centerline and other ramp base line intersection points or the crossroad centerline intersection point. The equations include offsets and intersection angles.

	Interchange ramps are numbered for ease of identification. Ramp details can be found on [~~http~~://www.modot.~~mo.gov/business/standards_and_specs~~/~~documents~~/~~20340.pdf~~ Standard Plan 203.40].		Interchange ramps are numbered for ease of identification. Ramp details can be found on [https://www.modot.org/media/16821 Standard Plan 203.40].

	The district approves the [[media:234.2 Figure 1 Diamond Interchange Alignment Controls.pdf\|geometric layout]] of a SPUI from the schematic drawing shown on the preliminary plan.		The district approves the [[media:234.2 Figure 1 Diamond Interchange Alignment Controls.pdf\|geometric layout]] of a SPUI from the schematic drawing shown on the preliminary plan.

Smithk: /* 234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type) */

2015-04-30T17:30:21Z

234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)

← Older revision		Revision as of 12:30, 30 April 2015
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	===234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)===		===234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)===

	Minimum speed change lengths are given in [[Media:Green Book Table 10-3.pdf\|Tables 10-3]] and [[Media:Green Book Table 10-5.pdf\|10-5]] of the AASHTO Green Book. Lengths shown in these tables are for grades of 2% or less on the speed change lane. [[Media:Green Book Table 10-4.pdf\|Table 10-4]] of the AASHTO Green Book provides adjustment to these lengths for grades over 2%. Speed change lanes are provided at all ramp entrances and exits where the number of through traffic lanes each side of the ramp terminal are equal. The combined length of full width acceleration lane and taper will not be less than 600 ft. A shoulder, at least 6 ft. wide, is provided for auxiliary lanes along the through traffic lanes (except a 4-foot shoulder will be provided along a median acceleration lane). Auxiliary lane width is the same as the width provided for the through traffic lanes. In rural areas, the ramp nose will be visible to approaching traffic for a distance equal to at least 1.25 times the stopping sight distance on the freeway		Minimum speed change lengths are given in [[Media:Green Book Table 10-3.pdf\|Tables 10-3]] and [[Media:Green Book Table 10-5.pdf\|10-5]] of the AASHTO Green Book. Lengths shown in these tables are for grades of 2% or less on the speed change lane. [[Media:Green Book Table 10-4.pdf\|Table 10-4]] of the AASHTO Green Book provides adjustment to these lengths for grades over 2%. Speed change lanes are provided at all ramp entrances and exits where the number of through traffic lanes each side of the ramp terminal are equal. The combined length of full width acceleration lane and taper will not be less than 600 ft. A shoulder, at least 6 ft. wide, is provided for auxiliary lanes along the through traffic lanes (except a 4-foot shoulder will be provided along a median acceleration lane). Auxiliary lane width is the same as the width provided for the through traffic lanes. In rural areas, the ramp nose will be visible to approaching traffic for a distance equal to at least 1.25 times the stopping sight distance on the freeway.

	Where interchanges are closely spaced the auxiliary lane for acceleration will be extended to the exit of the next interchange. An entrance lane followed by a lane exiting forms a traffic weaving section that requires added pavement width and length for weaving capacity. The capacity of the auxiliary lane connecting the on-ramp with the off-ramp will be determined using the Highway Capacity Manual or an appropriate traffic-modeling program (i.e. VISSIM). The weaving section will have a length and number of lanes based on the appropriate level of service outlined in the [[:category:232 Facility Selection\|Facility Selection]] article.		Where interchanges are closely spaced the auxiliary lane for acceleration will be extended to the exit of the next interchange. An entrance lane followed by a lane exiting forms a traffic weaving section that requires added pavement width and length for weaving capacity. The capacity of the auxiliary lane connecting the on-ramp with the off-ramp will be determined using the Highway Capacity Manual or an appropriate traffic-modeling program (i.e. VISSIM). The weaving section will have a length and number of lanes based on the appropriate level of service outlined in the [[:category:232 Facility Selection\|Facility Selection]] article.

Smithk at 14:53, 22 July 2014

2014-07-22T14:53:15Z

← Older revision		Revision as of 09:53, 22 July 2014
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			==234.4.1 Discussion==
			[[Image:234.4.1.jpg\|right\|425px]]

	[[~~Image~~:234.4.1.~~jpg~~\|~~right\|400px~~]]		A Single Point Urban Interchange (SPUI) is typically characterized by narrow right-of-way, high construction costs, and greater traffic capacity than conventional tight diamond interchanges. SPUIs usually function better without frontage roads. They are primarily suited for urban areas where right-of-way is restricted and expensive. [[media:234.4 Figure 1 Typical Geometrics for Single Point Urban Interchange.pdf\|Primary features]] of a SPUI are all four turning movements can be controlled by a single traffic signal. They may be selected as the best alternative for an improvement instead of a diamond interchange when the total right-of-way and construction costs are evaluated for each interchange type used to address traffic capacity.

	==234.4.1 ~~Discussion~~==		===234.4.1.1 Advantages===

	A ~~Single Point Urban Interchange (~~SPUI~~) is typically characterized~~ by narrow right-of-way~~, high construction costs, and greater traffic capacity than conventional tight diamond interchanges~~. ~~SPUIs usually function better without frontage roads~~. ~~They are primarily suited for urban areas where~~ right-of-~~way is restricted~~ and ~~expensive~~. ~~[[media:234.4 Figure 1 Typical Geometrics for Single Point Urban Interchange.pdf\|Primary features]] of~~ a ~~SPUI are all four turning movements can be controlled by~~ a ~~single~~ traffic signal. ~~They may be selected~~ as the ~~best alternative for an improvement instead~~ of a diamond interchange when the ~~total right-of-way and construction costs~~ are ~~evaluated for each~~ interchange ~~type used to address traffic capacity~~.		A SPUI offers several advantages including potentially significant right-of-way cost reductions by constructing it in a relatively narrow right-of-way. The primary operational advantage of this interchange configuration is the paths of vehicles making opposing left turns do not intersect. In addition, the right-turn movements are typically free-flow movements and only the left turns must pass through the signalized intersection. As a result, a major source of traffic conflict is eliminated, thus increasing overall intersection efficiency and reducing the signal operation needed from four-phases to three. Since the SPUI has only one intersection, as opposed to two for a diamond interchange, the operations of the single traffic signal may result in reduced delay through the intersection area when compared to a diamond interchange when turning movements are balanced. Radii for left-turn movements through the intersection are significantly larger than at conventional intersections so the left turns can move at higher speeds. These operational improvements may result in a higher capacity than a conventional tight diamond interchange.
	{\|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#ffddcc" width="210px" align="right"		{\|style="padding: 0.3em; margin-left:15px; border:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#ffddcc" width="210px" align="right"
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	\|'''See also:''' [http://www.modot.gov/services/OR/byDate.htm Innovation Library]		\|'''See also:''' [http://www.modot.gov/services/OR/byDate.htm Innovation Library]
	\|}		\|}
	~~===234.4.1.1 Advantages===~~

	A SPUI offers several advantages including potentially significant right-of-way cost reductions by constructing it in a relatively narrow right-of-way. The primary operational advantage of this interchange configuration is the paths of vehicles making opposing left turns do not intersect. In addition, the right-turn movements are typically free-flow movements and only the left turns must pass through the signalized intersection. As a result, a major source of traffic conflict is eliminated, thus increasing overall intersection efficiency and reducing the signal operation needed from four-phases to three. Since the SPUI has only one intersection, as opposed to two for a diamond interchange, the operations of the single traffic signal may result in reduced delay through the intersection area when compared to a diamond interchange when turning movements are balanced. Radii for left-turn movements through the intersection are significantly larger than at conventional intersections so the left turns can move at higher speeds. These operational improvements may result in a higher capacity than a conventional tight diamond interchange.

	===234.4.1.2 Disadvantages===		===234.4.1.2 Disadvantages===

Smithk: /* 234.4.1 Discussion */ new photo

2014-07-22T14:51:57Z

234.4.1 Discussion: new photo

← Older revision		Revision as of 09:51, 22 July 2014
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			[[Image:234.4.1.jpg\|right\|400px]]

	==234.4.1 Discussion==		==234.4.1 Discussion==

	~~[[Image:234 Photo3 Single Point Interchange.jpg\|left\|350px]]~~

	A Single Point Urban Interchange (SPUI) is typically characterized by narrow right-of-way, high construction costs, and greater traffic capacity than conventional tight diamond interchanges. SPUIs usually function better without frontage roads. They are primarily suited for urban areas where right-of-way is restricted and expensive. [[media:234.4 Figure 1 Typical Geometrics for Single Point Urban Interchange.pdf\|Primary features]] of a SPUI are all four turning movements can be controlled by a single traffic signal. They may be selected as the best alternative for an improvement instead of a diamond interchange when the total right-of-way and construction costs are evaluated for each interchange type used to address traffic capacity.		A Single Point Urban Interchange (SPUI) is typically characterized by narrow right-of-way, high construction costs, and greater traffic capacity than conventional tight diamond interchanges. SPUIs usually function better without frontage roads. They are primarily suited for urban areas where right-of-way is restricted and expensive. [[media:234.4 Figure 1 Typical Geometrics for Single Point Urban Interchange.pdf\|Primary features]] of a SPUI are all four turning movements can be controlled by a single traffic signal. They may be selected as the best alternative for an improvement instead of a diamond interchange when the total right-of-way and construction costs are evaluated for each interchange type used to address traffic capacity.

Smithk: Per Design, updated AASHTO figures

2013-01-04T20:15:46Z

Per Design, updated AASHTO figures

← Older revision		Revision as of 15:15, 4 January 2013
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	\|[[Media:234.2 Figure 5 Lane Drops for One And Two Lane Ramps.pdf\|"Escape Lane" (Lane Drop for One and Two Lane Ramps)]]		\|[[Media:234.2 Figure 5 Lane Drops for One And Two Lane Ramps.pdf\|"Escape Lane" (Lane Drop for One and Two Lane Ramps)]]
	\|-		\|-
	\|[[Media:~~234.2 Minimum Acceleration Lengths for Entrance Terminals~~.pdf\|'''Green Book ~~Exhibit~~ 10-70''', "Minimum Acceleration Lengths for Entrance Terminals"]]		\|[[Media:Green Book Table 10-3.pdf\|'''Green Book Table 10-3''', "Minimum Acceleration Lengths for Entrance Terminals"]]
	\|-		\|-
	\|[[Media:~~Speed Change Lane Adjustment Factors~~.pdf\|'''Green Book ~~Exhibit~~ 10-71''', "Speed Change Lane Adjustment Factors"]]		\|[[Media:Green Book Table 10-4.pdf\|'''Green Book Table 10-4''', "Speed Change Lane Adjustment Factors"]]
	\|-		\|-
	\|[[Media:~~234.2 Minimum Deceleration Lengths for Exit Terminals~~.pdf\|'''Green Book ~~Exhibit~~ 10-73''', "Minimum Deceleration Lengths for Exit Terminals"]]		\|[[Media:Green Book Table 10-5.pdf\|'''Green Book Table 10-5''', "Minimum Deceleration Lengths for Exit Terminals"]]
	\|-		\|-
	\|[[Media:~~234.2 Two Lane Exit Terminals~~.pdf\|'''Green Book ~~Exhibit~~ 10-76''', "Two Lane ~~Exit Terminals~~"]]		\|[[Media:Green Book Fig 10-73.pdf\|'''Green Book Figure 10-73''', "Typical Two-Lane Entrance Ramps"]]
	\|-		\|-
	\|[[Media:~~234.2 Typical Two~~-~~Lane Entrance Ramps~~.pdf\|'''Green Book ~~Exhibit~~ 10-77''', "~~Typical~~ Two-Lane ~~Entrance Ramps~~"]]		\|[[Media:Green Book Fig 10-74.pdf\|'''Green Book Figure 10-74''', "Two Lane Exit Terminals"]]
	\|-		\|-
	\|'''Video'''		\|'''Video'''
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	===234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)===		===234.4.1.6 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)===

	Minimum speed change lengths are given in [[Media:~~234.2 Minimum Acceleration Lengths for Entrance Terminals~~.pdf\|~~Exhibits~~ 10-70]] and [[Media:~~234.2 Minimum Deceleration Lengths for Exit Terminals~~.pdf\|10-73]] of the AASHTO Green Book. Lengths shown in these tables are for grades of 2% or less on the speed change lane. [[Media:~~Speed Change Lane Adjustment Factors~~.pdf\|~~Exhibit~~ 10-71]] of the AASHTO Green Book provides adjustment to these lengths for grades over 2%. Speed change lanes are provided at all ramp entrances and exits where the number of through traffic lanes each side of the ramp terminal are equal. The combined length of full width acceleration lane and taper will not be less than 600 ft. A shoulder, at least 6 ft. wide, is provided for auxiliary lanes along the through traffic lanes (except a 4-foot shoulder will be provided along a median acceleration lane). Auxiliary lane width is the same as the width provided for the through traffic lanes. In rural areas, the ramp nose will be visible to approaching traffic for a distance equal to at least 1.25 times the stopping sight distance on the freeway		Minimum speed change lengths are given in [[Media:Green Book Table 10-3.pdf\|Tables 10-3]] and [[Media:Green Book Table 10-5.pdf\|10-5]] of the AASHTO Green Book. Lengths shown in these tables are for grades of 2% or less on the speed change lane. [[Media:Green Book Table 10-4.pdf\|Table 10-4]] of the AASHTO Green Book provides adjustment to these lengths for grades over 2%. Speed change lanes are provided at all ramp entrances and exits where the number of through traffic lanes each side of the ramp terminal are equal. The combined length of full width acceleration lane and taper will not be less than 600 ft. A shoulder, at least 6 ft. wide, is provided for auxiliary lanes along the through traffic lanes (except a 4-foot shoulder will be provided along a median acceleration lane). Auxiliary lane width is the same as the width provided for the through traffic lanes. In rural areas, the ramp nose will be visible to approaching traffic for a distance equal to at least 1.25 times the stopping sight distance on the freeway

	Where interchanges are closely spaced the auxiliary lane for acceleration will be extended to the exit of the next interchange. An entrance lane followed by a lane exiting forms a traffic weaving section that requires added pavement width and length for weaving capacity. The capacity of the auxiliary lane connecting the on-ramp with the off-ramp will be determined using the Highway Capacity Manual or an appropriate traffic-modeling program (i.e. VISSIM). The weaving section will have a length and number of lanes based on the appropriate level of service outlined in the [[:category:232 Facility Selection\|Facility Selection]] article.		Where interchanges are closely spaced the auxiliary lane for acceleration will be extended to the exit of the next interchange. An entrance lane followed by a lane exiting forms a traffic weaving section that requires added pavement width and length for weaving capacity. The capacity of the auxiliary lane connecting the on-ramp with the off-ramp will be determined using the Highway Capacity Manual or an appropriate traffic-modeling program (i.e. VISSIM). The weaving section will have a length and number of lanes based on the appropriate level of service outlined in the [[:category:232 Facility Selection\|Facility Selection]] article.

	Where a two-lane entrance ramp or a two-lane exit ramp is needed for capacity or lane balance, the effective length of auxiliary lane will be determined as illustrated in [[Media:~~234.2 Two Lane Exit Terminals~~.pdf\|~~Exhibits~~ 10-76]] and [[Media:~~234.2 Typical Two~~-~~Lane Entrance Ramps~~.pdf\|10-77]] of the AASHTO Green Book.		Where a two-lane entrance ramp or a two-lane exit ramp is needed for capacity or lane balance, the effective length of auxiliary lane will be determined as illustrated in [[Media:Green Book Fig 10-74.pdf\|Figures 10-74]] and [[Media:Green Book Fig 10-73.pdf\|10-73]] of the AASHTO Green Book.

	===234.4.1.7 Clear Zones===		===234.4.1.7 Clear Zones===

Smithk: Addition of SPUI video

2010-07-08T13:28:46Z

Addition of SPUI video

← Older revision		Revision as of 08:28, 8 July 2010
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	{\|style="padding: 0.3em; margin-left:15px; border:~~1px~~ solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="~~160px~~" align="right"		{\|style="padding: 0.3em; margin-left:15px; border:2px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="250px" align="right"
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	\|'''Figures'''		\|'''Figures'''
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	\|-		\|-
	\|[[Media:234.2 Typical Two-Lane Entrance Ramps.pdf\|'''Green Book Exhibit 10-77''', "Typical Two-Lane Entrance Ramps"]]		\|[[Media:234.2 Typical Two-Lane Entrance Ramps.pdf\|'''Green Book Exhibit 10-77''', "Typical Two-Lane Entrance Ramps"]]
			\|-
			\|'''Video'''
			\|-
			\|[[media:234.4 SPUI June 2010.wmv\|A SPUI Under Construction]]
	\|}		\|}