232.2 Passing Lanes - Revision history

Smithk: /* 232.2.1 Discussion */

2021-07-28T18:45:06Z

232.2.1 Discussion

← Older revision		Revision as of 13:45, 28 July 2021
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	\|[[media:232.2.3.2.pdf\|Roadway Typical Section for Passing Lanes]]		\|[[media:232.2.3.2.pdf\|Roadway Typical Section for Passing Lanes]]
	\|-		\|-
	\|[https://www.modot.org/media/16900 Std. Plan 626.00 ~~Ruble~~ Strips]		\|[https://www.modot.org/media/16900 Std. Plan 626.00 Rumble Strips]
	\|-		\|-
	\|[[626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]		\|[[626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]
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	\|-		\|-
	\|}		\|}


	==232.2.2 Passing Lane Location==		==232.2.2 Passing Lane Location==

Smithk: Per TS, replaced now-archaic special sheet with link to new Std. Plan 626.00. Also updated typical section sheet to reflect new Std. Plan 626.00.

2021-07-27T18:36:06Z

Per TS, replaced now-archaic special sheet with link to new Std. Plan 626.00. Also updated typical section sheet to reflect new Std. Plan 626.00.

Smithk: Per TS, minor clarifications

2020-11-04T16:30:07Z

Per TS, minor clarifications

← Older revision		Revision as of 11:30, 4 November 2020
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	==232.2.1 Discussion==		==232.2.1 Discussion==

	A passing lane is an added lane provided in one or both directions of travel on a conventional two-lane highway to improve passing opportunities. This definition includes intermittent or continuous passing lanes in level or rolling terrain, and short four-lane sections. The objectives of using passing lanes on a two-lane highway are:		A passing lane is an added lane provided in one or both directions of travel on a conventional two-lane highway to improve passing opportunities. This definition includes intermittent or continuous passing lanes in level or rolling terrain and short four-lane sections. The objectives of using passing lanes on a two-lane highway are:
	{\|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:1px solid #a9a9a9; text-align:center; font-size: 95%; background:#f5f5f5" width="160px" align="right"
	\|-		\|-
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	\|'''Passing Lanes, Design/Location Criteria'''		\|'''Passing Lanes, Design/Location Criteria'''
	\|-		\|-
	\|[~~http~~://~~library~~.modot.mo.gov/~~RDT~~/~~reports~~/~~RI02018~~/RDT04008.pdf Report 2004]		\|[https://spexternal.modot.mo.gov/sites/cm/CORDT/RDT04008.pdf Report 2004]
	\|-		\|-
	\|'''See also:''' [https://www.modot.org/research-publications Research Publications]		\|'''See also:''' [https://www.modot.org/research-publications Research Publications]
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	* Average travel speed – the length of a highway segment divided by the average travel time of all vehicles traversing the segment during a designated interval of time		* Average travel speed – the length of a highway segment divided by the average travel time of all vehicles traversing the segment during a designated interval of time

	The Highway Capacity Manual contains methods to evaluate the capacity of a two-lane roadway with a passing lane. The operation of multiple passing lane sections on a corridor should be evaluated with software such as the TWOPAS traffic simulation module contained in the [http://www.tfhrc.gov/safety/ihsdm/tamweb.htm Interactive Highway Safety Design Model].		The ''Highway Capacity Manual'' contains methods to evaluate the capacity of a two-lane roadway with a passing lane.

	~~The level-of-service criteria for Two-Lane Highways is as follows:~~		Passing lanes have been found to increase average travel speed by as much as 8 to 11 percent, depending on traffic volume, within the passing lane itself. The speed benefits of passing lanes continue for approximately 2 miles downstream of the passing lane. Passing lanes typically reduce the percent time spent following by 58 to 62 percent, depending on traffic volume, within the passing lane itself. The percent time spent following benefits of passing lanes can continue up to 13 miles downstream of the passing lane.

	~~{\| border="1"~~
	~~!style="background:#FFD700"\|LOS!!style="background:#FFD700"\|Percent time spent following!!style="background:#FFD700"\|Average travel speed (mph)~~
	~~\|-style="background:#cccccc"~~
	~~\|align="center"\|A\|\|align="center"\|≤35\|\|align="center"\|>56~~
	~~\|-style="background:#cccccc"~~
	~~\|align="center"\|B\|\|align="center"\|>35-50\|\|align="center"\|>50-56~~
	~~\|-style="background:#cccccc"~~
	~~\|align="center"\|C\|\|align="center"\|>50-65\|\|align="center"\|>43-50~~
	~~\|-style="background:#cccccc"~~
	~~\|align="center"\|D\|\|align="center"\|>65-80\|\|align="center"\|>37-43~~
	~~\|-style="background:#cccccc"~~
	~~\|align="center"\|E\|\|align="center"\|>80\|\|align="center"\|≤37~~
	\|-
	~~\|style="background:#FFD700 colspan="3"\|Note: LOS F applies whenever the flow rate exceeds the segment capacity. (Source: Transportation Research Board, Highway Capacity Manual, 2000)~~
	\|-
	\|}

	Passing lanes have been found to increase average travel speed by as much as 8 to 11 percent, depending on traffic volume, within the passing lane itself. The speed benefits of passing lanes continue for approximately 2 mi downstream of the passing lane. Passing lanes typically reduce the percent time spent following by 58 to 62 percent, depending on traffic volume, within the passing lane itself. The percent time spent following benefits of passing lanes can continue up to 13 mi downstream of the passing lane.

	If the [[:Category:232 Facility Selection\|desired level of service]] for a project cannot be attained with a conventional two-lane highway, the addition of passing lanes is to be considered. For any project for which passing lanes are considered, the level of service for alternative [[232.2 Passing Lanes#232.2.3.1 Alternative Configurations \|passing lane configurations]] are evaluated to identify a configuration that provides the desired level of service. If the desired level of service cannot be attained with a configuration with maximum passing lanes, then a [[:Category:231 Typical Section Elements for Roadways\|four-lane cross section (D-61)]] is considered.		If the [[:Category:232 Facility Selection\|desired level of service]] for a project cannot be attained with a conventional two-lane highway, the addition of passing lanes is to be considered. For any project for which passing lanes are considered, the level of service for alternative [[232.2 Passing Lanes#232.2.3.1 Alternative Configurations \|passing lane configurations]] are evaluated to identify a configuration that provides the desired level of service. If the desired level of service cannot be attained with a configuration with maximum passing lanes, then a [[:Category:231 Typical Section Elements for Roadways\|four-lane cross section (D-61)]] is considered.
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	!style="background:#FFD700"\|Directional flow rate (pc/h)!!style="background:#FFD700"\|Passing lane length (mi)		!style="background:#FFD700"\|Directional flow rate (pc/h)!!style="background:#FFD700"\|Passing lane length (mi)
	\|-style="background:#cccccc"		\|-style="background:#cccccc"
	\|align="center"\|100\|\|align="center"\|≤0.50		\|align="center"\|Less than 100\|\|align="center"\|≤0.50
	\|-style="background:#cccccc"		\|-style="background:#cccccc"
	\|align="center"\|~~200~~\|\|align="center"\|>0.50-0.75		\|align="center"\|100 - 400\|\|align="center"\|>0.50-0.75
	\|-style="background:#cccccc"		\|-style="background:#cccccc"
	\|align="center"\|400\|\|align="center"\|>0.75-1.00		\|align="center"\|400 - 700\|\|align="center"\|>0.75-1.00
	\|-style="background:#cccccc"		\|-style="background:#cccccc"
	\|align="center"\|≥700\|\|align="center"\|>1.00-2.00		\|align="center"\|≥700\|\|align="center"\|>1.00-2.00
	\|-		\|-
	\|style="background:#FFD700 colspan="3"\|Source: Transportation Research Board, Highway Capacity Manual, ~~2000~~		\|style="background:#FFD700 colspan="3"\|Source: Transportation Research Board, Highway Capacity Manual, 6<sup>th</sup> Edition
	\|-		\|-
	\|}		\|}
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	==232.2.3 Passing Lane Design==		==232.2.3 Passing Lane Design==

	Where a ~~[http://www.tfhrc.gov/safety/ihsdm/tamweb.htm~~ capacity analysis] shows that a passing lane is needed, several possible configurations are to be evaluated.		Where a capacity analysis shows that a passing lane is needed, several possible configurations are to be evaluated.

	The recommended minimum transition distance between passing lanes in opposing directions is 500 ft. for "tail-to-tail" and 1,500 ft. for "head-to-head".		The recommended minimum transition distance between passing lanes in opposing directions is 500 ft. for "tail-to-tail" and 1,500 ft. for "head-to-head".
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	===232.2.3.1 Alternative Configurations===		===232.2.3.1 Alternative Configurations===

	Where a ~~[http://www.tfhrc.gov/safety/ihsdm/tamweb.htm~~ capacity analysis] shows that a passing lane is needed, several possible configurations are to be evaluated. The [[media:232.2 Basic Passing Lane Configuration.pdf\|basic layout]] of a passing lane is available. Alternative passing lane configurations and their typical applications are described in the following:		Where a capacity analysis shows that a passing lane is needed, several possible configurations are to be evaluated. The [[media:232.2 Basic Passing Lane Configuration.pdf\|basic layout]] of a passing lane is available. Alternative passing lane configurations and their typical applications are described in the following:

	[[image:232.2.3.1 Isolated Passing Lane.jpg\|center\|600px\|thumb\|<center>'''Isolated Passing Lane'''</center>		[[image:232.2.3.1 Isolated Passing Lane.jpg\|center\|600px\|thumb\|<center>'''Isolated Passing Lane'''</center>
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	[[image:232.2.3.1 Intermittent Passing Lanes, Adjoining head-to-head.jpg\|center\|600px\|thumb\|<center>'''Intermittent Passing Lanes, Adjoining Head-to-Head'''</center>		[[image:232.2.3.1 Intermittent Passing Lanes, Adjoining head-to-head.jpg\|center\|600px\|thumb\|<center>'''Intermittent Passing Lanes, Adjoining Head-to-Head'''</center>
	* Often used in pairs, one in each direction of travel, at regular intervals along a two-lane highway.		* Often used in pairs, one in each direction of travel, at regular intervals along a two-lane highway.
	<blockquote>* Buffer area between passing lanes ~~depends~~ in opposing directions is typically 1500 ft. or more.</blockquote>		<blockquote>* Buffer area between passing lanes in opposing directions is typically 1500 ft. or more.</blockquote>
	<blockquote>* Where a buffer area of sufficient length cannot be provided or where longer passing lanes are needed to achieve the desired level of service, overlapping passing lanes may be considered. See discussion of configurations of f and g below.</blockquote>]]		<blockquote>* Where a buffer area of sufficient length cannot be provided or where longer passing lanes are needed to achieve the desired level of service, overlapping passing lanes may be considered. See discussion of configurations of f and g below.</blockquote>]]

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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a ~~[http://www.modot.org/Shared4-Lane/Shared4Lane.htm~~ continuous three-lane section with alternating passing lanes], known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.

Smithk at 20:10, 18 August 2020

2020-08-18T20:10:21Z

← Older revision		Revision as of 15:10, 18 August 2020
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	\|[http://library.modot.mo.gov/RDT/reports/RI02018/RDT04008.pdf Report 2004]		\|[http://library.modot.mo.gov/RDT/reports/RI02018/RDT04008.pdf Report 2004]
	\|-		\|-
	\|'''See also:''' [~~http~~://www.modot.~~gov~~/~~services/OR/byDate.htm Innovation Library~~]		\|'''See also:''' [https://www.modot.org/research-publications Research Publications]
	\|}		\|}

Smithk: /* 232.2.3 Passing Lane Design */ updated link

2018-10-23T18:42:59Z

232.2.3 Passing Lane Design: updated link

← Older revision		Revision as of 13:42, 23 October 2018
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	[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.		[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.

	Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[626.2 Centerline Rumble Strips\|pavement marking]] and [~~http~~://www.modot.~~mo.gov/business/standards_and_specs~~/~~documents~~/~~62600.pdf~~ centerline rumble strip] (also see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]) provisions must be addressed.		Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[626.2 Centerline Rumble Strips\|pavement marking]] and [https://www.modot.org/media/16900 centerline rumble strip] (also see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]) provisions must be addressed.

	===232.2.3.1 Alternative Configurations===		===232.2.3.1 Alternative Configurations===

Smithk: updated links

2018-10-23T18:36:29Z

updated links

← Older revision		Revision as of 13:36, 23 October 2018
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	\|[[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]		\|[[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]
	\|-		\|-
	\|[[~~:Category:626 Rumble Strips#~~626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]		\|[[626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]
	\|-		\|-
	\|[[:Category:231 Typical Section Elements for Roadways\|Standard Roadway Typical Sections]]		\|[[:Category:231 Typical Section Elements for Roadways\|Standard Roadway Typical Sections]]
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	[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.		[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.

	Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[~~:Category:626 Rumble Strips#~~626.2 Centerline Rumble Strips\|pavement marking]] and [http://www.modot.mo.gov/business/standards_and_specs/documents/62600.pdf centerline rumble strip] (also see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]) provisions must be addressed.		Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[626.2 Centerline Rumble Strips\|pavement marking]] and [http://www.modot.mo.gov/business/standards_and_specs/documents/62600.pdf centerline rumble strip] (also see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]) provisions must be addressed.

	===232.2.3.1 Alternative Configurations===		===232.2.3.1 Alternative Configurations===

Smithk: /* 232.2.3.2 Geometric Aspects */

2017-01-25T13:44:54Z

232.2.3.2 Geometric Aspects

← Older revision		Revision as of 08:44, 25 January 2017
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section] with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section with alternating passing lanes], known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.

Smithk: /* 232.2.3.2 Geometric Aspects */

2017-01-25T13:44:08Z

232.2.3.2 Geometric Aspects

← Older revision		Revision as of 08:44, 25 January 2017
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section] with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.

Smithk: minor clarification

2010-04-01T16:12:42Z

minor clarification

← Older revision		Revision as of 11:12, 1 April 2010
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	Passing lanes can operate effectively with no separation between opposing lanes of travel. While no separation is required, AASHTO guidance recommends that some separation, however small, between the lanes in opposite directions of travel is desirable. Therefore, a flush separation of 4 ft. between the opposing directions of travel is preferred (see [[media:232.2 Passing Lane Typical Cross Section.pdf\|typical section]]), if at all possible.		Passing lanes can operate effectively with no separation between opposing lanes of travel. While no separation is required, AASHTO guidance recommends that some separation, however small, between the lanes in opposite directions of travel is desirable. Therefore, a flush separation of 4 ft. between the opposing directions of travel is preferred (see [[media:232.2 Passing Lane Typical Cross Section.pdf\|typical section]]), if at all possible.

	[[903.13 Typical Signing Applications#Figure 903.13.24 Typical Signing for Passing Lanes\|Signing and delineation]] are essential to the operation of passing lanes. Additional information concerning signing and marking of passing lanes can be found in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.2.1 Establishing and Recording No Passing Zones \|620.2 Pavement and Curb Markings (MUTCD Chapter 3B)]].		[[903.13 Typical Signing Applications#Figure 903.13.24 Typical Signing for Passing Lanes\|Signing and delineation]] are essential to the operation of passing lanes. Additional information concerning signing and marking of passing lanes can be found in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.2.1 Establishing and Recording No Passing Zones \|EPG 620.2 Pavement and Curb Markings (MUTCD Chapter 3B)]].

	[[Category:232 Facility Selection]]		[[Category:232 Facility Selection]]

Smithk: /* 232.2.3.2 Geometric Aspects */alternating passing lane sign photo added

2009-12-17T15:20:49Z

232.2.3.2 Geometric Aspects: alternating passing lane sign photo added

← Older revision		Revision as of 10:20, 17 December 2009
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
			[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

← Older revision		Revision as of 08:44, 25 January 2017
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section] with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section with alternating passing lanes], known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.

← Older revision		Revision as of 08:44, 25 January 2017
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a [http://www.modot.org/Shared4-Lane/Shared4Lane.htm continuous three-lane section] with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.

← Older revision		Revision as of 10:20, 17 December 2009
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
			[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media:232.2 Passing Lane Special Sheet.pdf\|Passing Lane Special Sheet]]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

← Older revision		Revision as of 13:36, 27 July 2021
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	\|'''Figures'''		\|'''Figures'''
	\|-		\|-
	\|[[media:232.2 ~~Passing Lane Typical Cross Section~~.pdf\|Roadway Typical Section for Passing Lanes]]		\|[[media:232.2.3.2.pdf\|Roadway Typical Section for Passing Lanes]]
	\|-		\|-
	\|[[media~~:232~~.~~2 Passing Lane Special Sheet~~.~~pdf\|Passing Lane Special Sheet]~~]		\|[https://www.modot.org/media/16900 Std. Plan 626.00 Ruble Strips]
	\|-		\|-
	\|[[626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]		\|[[626.2 Centerline Rumble Strips\|Centerline Pavement Marking]]
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	[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.		[[231.3 Lane Width\|Lane]] and [[231.4 Shoulder Width\|shoulder widths]] in passing lane sections are to be consistent with adjacent sections of two-lane highway, unless reduced widths would substantially reduce costs.

	Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[626.2 Centerline Rumble Strips\|pavement marking]] and [https://www.modot.org/media/16900 centerline rumble strip] (also see [[media~~:232~~.~~2 Passing Lane Special Sheet~~.~~pdf\|Passing Lane Special Sheet]~~]) provisions must be addressed.		Some separation between lanes in opposite directions of travel is desirable; however, passing lanes can operate effectively with no separation. However in either situation, [[626.2 Centerline Rumble Strips\|pavement marking]] and [https://www.modot.org/media/16900 centerline rumble strip] (also see [https://www.modot.org/media/16900 Std. Plan 626.00 Rumble Strips]) provisions must be addressed.

	===232.2.3.1 Alternative Configurations===		===232.2.3.1 Alternative Configurations===
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	Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.		Transitions between passing lanes in opposing directions are carefully designed; intersections, bridges, two-way left-turn lanes or painted medians can often be used effectively to provide a buffer area between opposing passing lanes. The [[media:232.2 Buffer Length Between Opposing Passing Lanes.pdf\|length of the buffer area]] between adjoining passing lanes depends on whether the configuration is "tail-to-tail" (Configuration "d") or "head-to-head" (Configuration "e"). For a pair of "tail-to-tail" passing lanes, the buffer area is typically 500 ft. or more, but the adjoining passing lanes may be located immediately adjacent to one another. For a pair of "head-to-head" passing lanes, the buffer area is typically 1,500 ft. or more.
	[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]		[[image:232.2.3.2.jpg\|right\|190px\|thumb\|<center>'''Configuration "i" illustrates a continuous 3-lane section with alternating passing lanes'''</center>]]
	Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [[media~~:232~~.~~2 Passing Lane Special Sheet~~.~~pdf\|Passing Lane Special Sheet]~~]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.		Configuration "i" illustrates a continuous three-lane section with alternating passing lanes, known as a "shared 4-lane" (also known as a 2+1) roadway (see [https://www.modot.org/media/16900 Std. Plan 626.00 Rumble Strips]). When volume demand exceeds the capacity of a shared 4-lane roadway, a four-lane cross section is to be considered.

	Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.		Typical [[231.4 Shoulder Width\|shoulder widths]] are to be used throughout the length of the passing lane unless a reduced shoulder width would substantially reduce costs. Whenever practical, the shoulder width in a passing lane section is not to be narrower than the shoulder width on the adjacent sections of two-lane highway. In no case shall the shoulder width be less than 4 ft. Typical lane widths of 12 ft. are to be used throughout the length of the passing lane unless a reduced lane width would substantially reduce costs. In general, the lane width is to be the same as the lane width on the adjacent sections of two-lane highway.
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	The length for a lane addition taper is to be at least 360 ft. for a 60-mph design speed. The length for a lane drop taper is computed using the MUTCD formula L = WS, where L is the taper length in feet, W is the width of the dropped lane in feet, and S is the off-peak 85th percentile speed in miles per hour. A wide shoulder is desirable at the lane drop taper to provide a recovery area should drivers encounter a merging conflict. Safe and effective passing lane operations require adequate sight distance on the approach to lane addition and lane drop tapers.		The length for a lane addition taper is to be at least 360 ft. for a 60-mph design speed. The length for a lane drop taper is computed using the MUTCD formula L = WS, where L is the taper length in feet, W is the width of the dropped lane in feet, and S is the off-peak 85th percentile speed in miles per hour. A wide shoulder is desirable at the lane drop taper to provide a recovery area should drivers encounter a merging conflict. Safe and effective passing lane operations require adequate sight distance on the approach to lane addition and lane drop tapers.

	Passing lanes can operate effectively with no separation between opposing lanes of travel. While no separation is required, AASHTO guidance recommends that some separation, however small, between the lanes in opposite directions of travel is desirable. Therefore, a flush separation of 4 ft. between the opposing directions of travel is preferred (see [[media:232.2 ~~Passing Lane Typical Cross Section~~.pdf\|typical section]]), if at all possible.		Passing lanes can operate effectively with no separation between opposing lanes of travel. While no separation is required, AASHTO guidance recommends that some separation, however small, between the lanes in opposite directions of travel is desirable. Therefore, a flush separation of 4 ft. between the opposing directions of travel is preferred (see [[media:232.2.3.2.pdf\|typical section]]), if at all possible.

	[[903.13 Typical Signing Applications#Figure 903.13.24 Typical Signing for Passing Lanes\|Signing and delineation]] are essential to the operation of passing lanes. Additional information concerning signing and marking of passing lanes can be found in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.2.1 Establishing and Recording No Passing Zones \|EPG 620.2 Pavement and Curb Markings (MUTCD Chapter 3B)]].		[[903.13 Typical Signing Applications#Figure 903.13.24 Typical Signing for Passing Lanes\|Signing and delineation]] are essential to the operation of passing lanes. Additional information concerning signing and marking of passing lanes can be found in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.2.1 Establishing and Recording No Passing Zones \|EPG 620.2 Pavement and Curb Markings (MUTCD Chapter 3B)]].

	[[Category:232 Facility Selection]]		[[Category:232 Facility Selection]]