234.3 Directional Interchanges - Revision history

Hoskir: /* 234.3.9 Grading */ changed GeoPak to OpenRoads Designer

2024-01-16T15:32:29Z

234.3.9 Grading: changed GeoPak to OpenRoads Designer

← Older revision		Revision as of 10:32, 16 January 2024
Line 201:		Line 201:
	==234.3.9 Grading==		==234.3.9 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.

	==234.3.10 Site Grading==		==234.3.10 Site Grading==

Smithk: /* 234.3.9 Grading */ Per CADD, deleted some CADD links

2019-06-24T15:11:25Z

234.3.9 Grading: Per CADD, deleted some CADD links

← Older revision		Revision as of 10:11, 24 June 2019
Line 201:		Line 201:
	==234.3.9 Grading==		==234.3.9 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.

	==234.3.10 Site Grading==		==234.3.10 Site Grading==

Smithk at 19:14, 28 September 2018

2018-09-28T19:14:54Z

← Older revision		Revision as of 14:14, 28 September 2018
Line 45:		Line 45:
	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:234.2 Figure 1 Diamond Interchange Alignment Controls.pdf\|geometric layout]] of a directional 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:234.2 Figure 1 Diamond Interchange Alignment Controls.pdf\|geometric layout]] of a directional 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: /* 234.3.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type) */

2015-04-30T17:28:09Z

234.3.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)

← Older revision		Revision as of 12:28, 30 April 2015
Line 121:		Line 121:
	==234.3.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)==		==234.3.4 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: new photo

2013-11-07T18:38:11Z

new photo

← Older revision		Revision as of 13:38, 7 November 2013
Line 257:		Line 257:

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

			[[image:234.3.15.jpg\|center\|1075px]]

	[[category:234 Interchanges]]		[[category:234 Interchanges]]

Smithk: /* 234.3.7 Superelevation */ added Green Book reference

2013-06-17T12:25:46Z

234.3.7 Superelevation: added Green Book reference

← Older revision		Revision as of 07:25, 17 June 2013
Line 141:		Line 141:

	{\| BORDER="1" style="text-align:center" cellpadding="3" align="center"		{\| BORDER="1" style="text-align:center" cellpadding="3" align="center"
	\|+ '''TABLE 3, Minimum Radii (ft.) for Design Superelevation Rates, ''e''<sub>max</sub> = 6%'''		\|+ '''TABLE 3, Green Book Table 3-9'''
			\|-
			\|+'''Minimum Radii (ft.) for Design Superelevation Rates, ''e''<sub>max</sub> = 6%'''
	\|-style="background:#F0C68C "		\|-style="background:#F0C68C "
	!rowspan="2"\|''e'' (%) !!colspan="14"\|Anticipated Posted Speed		!rowspan="2"\|''e'' (%) !!colspan="14"\|Anticipated Posted Speed

Smithk: /* 234.3.7 Superelevation */

2013-06-13T20:20:06Z

234.3.7 Superelevation

← Older revision		Revision as of 15:20, 13 June 2013
Line 143:		Line 143:
	\|+ '''TABLE 3, Minimum Radii (ft.) for Design Superelevation Rates, ''e''<sub>max</sub> = 6%'''		\|+ '''TABLE 3, Minimum Radii (ft.) for Design Superelevation Rates, ''e''<sub>max</sub> = 6%'''
	\|-style="background:#F0C68C "		\|-style="background:#F0C68C "
	!rowspan="2"\|''e'' (%) !!colspan="14"\|Anticipated Posted Speed~~, mph~~		!rowspan="2"\|''e'' (%) !!colspan="14"\|Anticipated Posted Speed
	\|-		\|-
	\|-style="background:#F0C68C"		\|-style="background:#F0C68C"
	!15\|\|20\|\|25\|\|30\|\|35\|\|40\|\|45\|\|50\|\|55\|\|60\|\|65\|\|70\|\|75\|\|80		!15<br>mph\|\|20<br>mph\|\|25<br>mph\|\|30<br>mph\|\|35<br>mph\|\|40<br>mph\|\|45<br>mph\|\|50<br>mph\|\|55<br>mph\|\|60<br>mph\|\|65<br>mph\|\|70<br>mph\|\|75<br>mph\|\|80<br>mph
	\|-		\|-
	\|'''Normal Crown'''\|\|868\|\|1580\|\|2290\|\|3130\|\|4100\|\|5230\|\|6480\|\|7870\|\|9410\|\|11100\|\|12600\|\|14100\|\|15700\|\|17400		\|'''Normal Crown'''\|\|868\|\|1580\|\|2290\|\|3130\|\|4100\|\|5230\|\|6480\|\|7870\|\|9410\|\|11100\|\|12600\|\|14100\|\|15700\|\|17400

Smithk: /* 234.3.7 Superelevation */ added table for min. radii for 6% superelevation (AASHTO Table 3-9, 2011)

2013-06-13T20:13:53Z

234.3.7 Superelevation: added table for min. radii for 6% superelevation (AASHTO Table 3-9, 2011)

@@ Line 138: / Line 138: @@
 ==234.3.7 Superelevation==
-Minimum controls for superelevation of short radius curves on ramps are shown in [[#TABLE 2| Table 2]].  A maximum super elevation rate of 6% is used when a short radius curve is on a bridge structure.  This is the maximum superelevation suitable for satisfactory traffic safety under snow and ice conditions.  The maximum rate of cross slope change is 5% per 100 ft. to transition the superelevation cross slope back to normal cross slope.  Ramp entrances and exits are designed to reach full superelevation at the ramp nose, if full superelevation can be obtained at this point.  Superelevation transition for typical ramp entrances and exits are shown on standard plans.  At ramp terminals with the thruway, the maximum algebraic difference in pavement cross slope is 5%.
+Minimum controls for superelevation of short radius curves on ramps are shown in [[#TABLE 2| Table 2]].  A maximum super elevation rate of 6% is used (refer to Table 3, below) when a short radius curve is on a bridge structure.  This is the maximum superelevation suitable for satisfactory traffic safety under snow and ice conditions.  The maximum rate of cross slope change is 5% per 100 ft. to transition the superelevation cross slope back to normal cross slope.  Ramp entrances and exits are designed to reach full superelevation at the ramp nose, if full superelevation can be obtained at this point.  Superelevation transition for typical ramp entrances and exits are shown on standard plans.  At ramp terminals with the thruway, the maximum algebraic difference in pavement cross slope is 5%.
 ==234.3.8 Grades==

Smithk: Per Design, updated AASHTO figures

2013-01-04T20:08:29Z

Per Design, updated AASHTO figures

← Older revision		Revision as of 15:08, 4 January 2013
Line 20:		Line 20:
	\|[[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"]]
	\|}		\|}

Line 122:		Line 121:
	==234.3.4 Auxiliary Lanes for Acceleration and Deceleration (Parallel Type)==		==234.3.4 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.

	==234.3.5 Clear Zones==		==234.3.5 Clear Zones==

Smithk: /* 234.3.10 Site Grading */ removed archaic links, per CM

2010-07-02T16:57:32Z

234.3.10 Site Grading: removed archaic links, per CM

← Older revision		Revision as of 11:57, 2 July 2010
Line 151:		Line 151:
	==234.3.10 Site Grading==		==234.3.10 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.