234.5 Cloverleaf Interchanges - Revision history

Hoskir: /* 234.5.9 Grading */ changed GeoPak to OpenRoads Designer

2024-01-16T15:44:53Z

234.5.9 Grading: changed GeoPak to OpenRoads Designer

← Older revision		Revision as of 10:44, 16 January 2024
Line 152:		Line 152:
	==234.5.9 Grading==		==234.5.9 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.

	==234.5.10 Site Grading==		==234.5.10 Site Grading==

Smithk: /* 234.5.9 Grading */ Per CADD, removed CADD links

2019-06-24T15:13:19Z

234.5.9 Grading: Per CADD, removed CADD links

← Older revision		Revision as of 10:13, 24 June 2019
Line 152:		Line 152:
	==234.5.9 Grading==		==234.5.9 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.

	==234.5.10 Site Grading==		==234.5.10 Site Grading==

Smithk at 19:16, 28 September 2018

2018-09-28T19:16:38Z

← Older revision		Revision as of 14:16, 28 September 2018
Line 50:		Line 50:
	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 [[media:234.5 Cloverleaf Design.pdf\|geometric layout]] of a cloverleaf interchange is prepared by the district and includes a plan sheet and a profile grade sheet. This information is submitted to the Design Division for review and comment.		The [[media:234.5 Cloverleaf Design.pdf\|geometric layout]] of a cloverleaf interchange is prepared by the district and includes a plan sheet and a profile grade sheet. This information is submitted to the Design Division for review and comment.

Smithk: /* 234.5.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type) */

2015-04-30T17:30:43Z

234.5.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)

← Older revision		Revision as of 12:30, 30 April 2015
Line 126:		Line 126:
	==234.5.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)==		==234.5.4 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 20:25, 4 January 2013

2013-01-04T20:25:51Z

← Older revision		Revision as of 15:25, 4 January 2013
Line 21:		Line 21:
	\|[[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:Green Book Fig 10-68.pdf\|'''Green Book ~~Exhibit~~ 10-68''', "Minimum Ramp Spacing"]]		\|[[Media:Green Book Fig 10-68.pdf\|'''Green Book Figure 10-68''', "Minimum Ramp Spacing"]]
	\|-		\|-
	\|[[Media:Green Book Table 10-3.pdf\|'''Green Book Table 10-3''', "Minimum Acceleration Lengths for Entrance Terminals"]]		\|[[Media:Green Book Table 10-3.pdf\|'''Green Book Table 10-3''', "Minimum Acceleration Lengths for Entrance Terminals"]]

Smithk: Per Design, updated AASHTO figures

2013-01-04T20:25:14Z

Per Design, updated AASHTO figures

Smithk: /* 234.5.10 Site Grading */ removed archaic links, per CM

2010-07-02T16:59:50Z

234.5.10 Site Grading: removed archaic links, per CM

← Older revision		Revision as of 11:59, 2 July 2010
Line 156:		Line 156:
	==234.5.10 Site Grading==		==234.5.10 Site Grading==

	Grading quantities in interchange areas ~~([[Section_200#ITEM NO: 203-10.00 (203-10.05)\|~~ Class A]], ~~[[Section_200#ITEM NO: 203-20.00 (203-20.05)\|~~Class C]] or ~~[[Section_200#ITEM NO: 203-50.00 (203-50.05)\|~~Unclassified Excavation~~]])~~ will include site grading necessary to properly handle drainage, to improve appearance, and to eliminate poor sight distance of other intersections. Where possible site grading is done for all interchange areas. Preliminary plans are reviewed carefully to determine if minimal site grading will address these items and yet provide economy in the design.		Grading quantities in interchange areas Class A, Class C or Unclassified Excavation will include site grading necessary to properly handle drainage, to improve appearance, and to eliminate poor sight distance of other intersections. Where possible site grading is done for all interchange areas. Preliminary plans are reviewed carefully to determine if minimal site grading will address these items and yet provide economy in the design.

	Where site grading of an interchange area is made, it is desirable to provide flat slopes and smooth contour lines. Slopes on the outside of ramps will not be steeper than 1:3 and carried back to its intersection with the mainline roadway.		Where site grading of an interchange area is made, it is desirable to provide flat slopes and smooth contour lines. Slopes on the outside of ramps will not be steeper than 1:3 and carried back to its intersection with the mainline roadway.

Smithk: minor clarifications

2010-04-02T13:28:08Z

minor clarifications

Smithk: article construction

2009-07-27T14:07:09Z

article construction

Show changes

EPG-Admin: reorient picture to uncover some text

2009-02-04T18:50:59Z

reorient picture to uncover some text

← Older revision		Revision as of 13:50, 4 February 2009
Line 24:		Line 24:
	==234.5.1 Introduction==		==234.5.1 Introduction==

	~~[[Image:234 Photo4 Cloverleaf Interchange.jpg\|left\|350px]]~~

	'''Advantages'''		'''Advantages'''

	* A configuration with loop ramps to safely accommodate left-turning movements that is well suited for the intersection of two freeways.		* A configuration with loop ramps to safely accommodate left-turning movements that is well suited for the intersection of two freeways.
			[[Image:234 Photo4 Cloverleaf Interchange.jpg\|right\|350px]]
	* Well suited for use in rural or suburban locations where space is available.		* Well suited for use in rural or suburban locations where space is available.

← Older revision		Revision as of 08:28, 2 April 2010
Line 122:		Line 122:
	Chapter 10 of the AASHTO Green Book has additional information concerning the coordination of lane balance and the basic number of lanes.		Chapter 10 of the AASHTO Green Book has additional information concerning the coordination of lane balance and the basic number of lanes.

	Major fork and branch connection designs with appropriate signing (see [[:category:903 Highway Signing\|903 Signing]]) to designate the optional exit lane destinations may be considered where appropriate as discussed in the AASHTO Green Book. Separate lanes with separate lane use signing are preferred where major forks occur.		Major fork and branch connection designs with appropriate signing (see [[:category:903 Highway Signing\|EPG 903 Highway Signing]]) to designate the optional exit lane destinations may be considered where appropriate as discussed in the AASHTO Green Book. Separate lanes with separate lane use signing are preferred where major forks occur.

	==234.5.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)==		==234.5.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)==
Line 183:		Line 183:
	* The mainline and crossroads are well lighted		* The mainline and crossroads are well lighted
	* Good lighting is provided at the ramp junctions.		* Good lighting is provided at the ramp junctions.
	* Detailed information is contained in [[:category:901 Lighting\|901, Lighting]].		* Detailed information is contained in [[:category:901 Lighting\|EPG 901 Lighting]].

	'''Signing''':		'''Signing''':
Line 192:		Line 192:
	* Traffic guide sign applications on the exit ramps are to be consistent with mainline signing.		* Traffic guide sign applications on the exit ramps are to be consistent with mainline signing.
	* Use advance signing such as lane use signs over each lane on the roadway approaching the interchange. The sign support structure is placed at or just beyond the point where the turn lane is fully developed.		* Use advance signing such as lane use signs over each lane on the roadway approaching the interchange. The sign support structure is placed at or just beyond the point where the turn lane is fully developed.
	* Detailed information is contained in [[:category:903 Highway Signing\|903, Signing]]		* Detailed information is contained in [[:category:903 Highway Signing\|EPG 903 Signing]]

	'''Pavement marking''':		'''Pavement marking''':

	* Appropriate pavement marking is provided in the interchange to avoid motorist confusion.		* Appropriate pavement marking is provided in the interchange to avoid motorist confusion.
	* Detailed information is contained in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)\|620.2 Pavement and Curb Markings]].		* Detailed information is contained in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)\|EPG 620.2 Pavement and Curb Markings]].

	==234.5.15 Maintenance and Emergency Crossovers==		==234.5.15 Maintenance and Emergency Crossovers==
Line 207:		Line 207:
	Maintenance crossovers may be needed at one or both ends of interchange facilities, depending on the type of interchange.		Maintenance crossovers may be needed at one or both ends of interchange facilities, depending on the type of interchange.

	Information concerning their location and requirements for construction can be found at [[:Category:240 Maintenance and Emergency Crossovers\|240 Maintenance and Emergency Crossovers]].		Information concerning their location and requirements for construction can be found at [[:Category:240 Maintenance and Emergency Crossovers\|EPG 240 Maintenance and Emergency Crossovers]].
	[[category:234 Interchanges]]		[[category:234 Interchanges]]