Difference between revisions of "620.8 Islands"

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m (620.7 Islands (MUTCD Chapter 3G) moved to 620.8 Islands: Per Traffic, revision to bring policy into substantial compliance with the 2009 MUTCD.)
m (Per TS, MoDOT no longer uses buttons)
 
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==620.7.1 General (MUTCD Section 3G.01)==
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==620.8.1 General (MUTCD Section 3I.01)==
  
'''Support.''' This addresses the characteristics of islands as traffic-control devices. Criteria for the design of islands are set forth in [[233.2 At-Grade Intersections with Stop and Yield Control#233.2.12 Islands|At-Grade Intersections with Stop and Yield Control]] and [[233.4 At-Grade Intersections with Signal Control#233.4.1.8 Islands|At-Grade Intersections with Signal Control]].
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'''Support.''' This addresses the characteristics of islands as traffic-control devices. Criteria for the design of islands are set forth in [[233.2 At-Grade Intersections with Stop and Yield Control#233.2.12 Islands|At-Grade Intersections with Stop and Yield Control]] and [[233.4 At-Grade Intersections with Signal Control#233.4.8 Islands|At-Grade Intersections with Signal Control]]. Also see ''MUTCD'' Section 1A.11 and ''A Policy on Geometric Design of Highways and Streets.''
  
'''Standard.''' An island for traffic control purposes shall be the defined area between traffic lanes for control of vehicular movements or for pedestrian refuge.  Within an intersection area, a median or an outer separation shall be an island.
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'''Option.''' An island may be designated by curbs, pavement edges, pavement markings, channelizing devices or other devices.
  
'''Option.''' An island may be designated by pavement markings, channelizing devices, curbs, pavement edges, or other devices.
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==620.8.2 Approach-End Treatment (MUTCD Section 3I.02)==
  
==620.7.2 Approach-End Treatment (MUTCD Section 3G.02)==
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'''Guidance.''' The ends of islands first approached by traffic should be preceded by  diverging longitudinal pavement markings on the roadway surface, to guide vehicles into desired paths of travel along the island edge.
  
'''Guidance.''' The ends of islands first approached by traffic should be preceded by a gradually diverging marking on the roadway surface, to guide vehicles into desired paths of travel along the island edge.
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'''Standard.''' Channelizing devices, when used in advance of islands having raised curbs, shall not be placed in such a manner as to constitute an unexpected obstacle.
  
'''Option.''' Approach-end markings that can be readily crossed even at considerable speed may contain slightly raised (usually less than 1 in. tall) sections of coarse aggregate or other suitable materials to create rumble sections that provide increased visibility of the marked areas and that produce an audible warning to road users traveling across them.
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'''Option.''' Pavement markings may be used with raised bars to better designate the island area.
  
'''Standard.''' Rumble strips or other devices, when used in advance of islands having raised curbs, shall not be placed in such a manner as to constitute an unexpected obstacle.
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==620.8.3 Island Marking Application (MUTCD Section 3I.03)==
  
'''Guidance'''. Bars or buttons should not project more than 1 to 3 in. above the pavement surface and should be designed so that any wheel encroachment within the area will be obvious to the vehicle operator, but will not result in loss of control of the vehicle.
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'''Standard.''' Markings, as related to islands, shall consist only of pavement and curb markings, channelizing devices and delineators.
  
'''Option.''' Bars or buttons may be preceded by rumble sections, or their height may be gradually increased as approached by traffic.
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'''Option.''' Pavement markings as described in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.10 Approach Markings for Obstructions (MUTCD Section 3B.10)|EPG 620.2.10 Approach Markings for Obstructions]] for the approach to an obstruction may be omitted on the approach to a particular island based on engineering judgment.
  
Pavement markings may be used with raised bars to better designate the island area.
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==620.8.4 Island Marking Colors (MUTCD Section 3I.04)==
  
==620.7.3 Island Marking Application (MUTCD Section 3G.03)==
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'''Guidance.''' Islands outlined by curbs or pavement markings should be marked with retroreflective white or yellow material as determined by the direction or directions of travel they separate (see [[620.1 General (MUTCD Chapter 3A)#620.1.5 Colors (MUTCD Section 3A.05)|EPG 620.1.5 Colors]]).
  
'''Standard.''' Markings, as related to islands, shall consist only of pavement and curb markings, object markers, and delineators.
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Island curbs with non-mountable curbs at least 6 in. tall shall be marked with retroreflective markings or delineators.
  
On the approach to islands, the triangular neutral area in advance of the end of the island shall include pavement markings as described in [[620.2 Pavement and Curb Markings (MUTCD Chapter 3B)#620.2.10 Approach Markings for Obstructions (MUTCD Section 3B.10)|Approach Markings for Obstructions (MUTCD Section 3B.10)]].
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The retroreflective area should be of sufficient length to denote the general alignment of the edge of the island along which vehicles travel, including the approach end, when viewed from the approach to the island.
  
'''Option.''' As indicated in [[#Approach-End Treatment (MUTCD Section 3G.02)|Approach-End Treatment (MUTCD Section 3G.02)]], rumble sections, or other similar traffic control designs which contrast with the pavement surface, may also be applied in the triangular neutral area in advance of the end of an island.
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'''Option.''' On long islands, curb retroreflection may be discontinued so that it does not extend for the entire length of the curb, especially if the island is illuminated or marked with delineators or edgelines.
  
'''Guidance.''' When raised bars or buttons are used in these neutral areas, they should be marked with white or yellow retroreflective materials, as determined by the direction or directions of travel they separate.
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An island with mountable curbs less than 3 in. tall may be marked with retroreflective markings or delineators.
  
==620.7.4 Island Marking Colors (MUTCD Section 3G.04)==
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==620.8.5 Island Delineation (MUTCD Section 3I.05)==
  
'''Guidance.''' Islands outlined by curbs or pavement markings should be marked with retroreflective white or yellow material as determined by the direction or directions of travel they separate (see [[620.1 General (MUTCD Chapter 3A)#620.1.4 Colors (MUTCD Section 3A.04)|Colors (MUTCD Section 3A.04)]]).
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'''Standard.''' Delineators installed on islands shall be the same colors as the related edge lines except that, when facing wrong-way traffic, they shall be red (see [[620.5 Delineators (MUTCD Chapter 3F)#620.5.3 Delineator Application (MUTCD Section 3F.03)|EPG 620.5.3 Delineator Application]]).
  
'''Standard.''' Island curbs with non-mountable curbs at least 6 in. tall shall be marked with retroreflective markings or delineators.
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Each roadway through an intersection shall be considered separately in positioning delineators to assure maximum effectiveness.
 
 
The retroreflective area should be of sufficient length to denote the general alignment of the edge of the island along which vehicles travel, including the approach nose, when viewed from the approach to the island.
 
 
 
'''Option.''' On long islands, curb retroreflection may be discontinued such that it does not extend for the entire length of the curb, especially if the island is illuminated or marked with delineators or edge lines.
 
 
 
An island with mountable curbs less than 3 in. tall may be marked with retroreflective markings or delineators.
 
 
 
==620.7.5 Island Object Markers (MUTCD Section 3G.05)==
 
  
'''Option.''' Object markers may be installed alone or in combination with signs (such as KEEP RIGHT, KEEP LEFT, double arrows, or guide signs) located within the island.
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'''Option.''' Retroreflective or internally illuminated raised pavement markers of the appropriate color may be placed on the pavement in front of the curb and/or on the top of curbed approach ends of raised medians and curbs of islands, as a supplement to or as a substitute for retroreflective curb markings.
  
==620.7.6 Island Delineators (MUTCD Section 3G.06)==
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==620.8.6 Pedestrian Islands and Medians (MUTCD Section 3I.06)==
  
'''Standard.''' Delineators installed on islands shall be the same colors as the related edge lines except that, when facing wrong-way traffic, they shall be red (see [[620.4 Delineators (MUTCD Chapter 3D)#620.4.3 Delineator Application (MUTCD Section 3D.03)|Delineator Application (MUTCD Section 3D.03)]]).
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'''Support.''' Raised islands or medians of sufficient width that are placed in the center area of a street or highway can serve as a place of refuge for pedestrians who are attempting to cross at a midblock or intersection location. Center islands or medians allow pedestrians to find an adequate gap in one direction of traffic at a time, as the pedestrians are able to stop, if necessary, in the center island or median area and wait for an adequate gap in the other direction of traffic before crossing the second half of the street or highway. The minimum widths for accessible refuge islands and for design and placement of detectable warning surfaces are provided in the [https://www.access-board.gov/guidelines-and-standards/buildings-and-sites/about-the-ada-standards/background/adaag ''Americans with Disabilities Act Accessibility Guidelines for Buildings and Facilities (ADAAG)''] (see ''MUTCD'' Section 1A.11).
  
Each roadway through an intersection shall be considered separately in positioning delineators to assure maximum effectiveness.
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<div id="Fig. 620.8.6"></div>
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[[Image:620.9.6.jpg|thumb|center|700px|<center>'''Fig. 620.8.6, Markings for Islands Painted and Raised'''</center>]]
  
[[Image:620.7 Markings for Islands Painted and Raised.gif]]
 
  
[[Category:620 Pavement Marking|620.07]]
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[[Category:620 Pavement Marking|620.08]]

Latest revision as of 12:39, 4 September 2020

620.8.1 General (MUTCD Section 3I.01)

Support. This addresses the characteristics of islands as traffic-control devices. Criteria for the design of islands are set forth in At-Grade Intersections with Stop and Yield Control and At-Grade Intersections with Signal Control. Also see MUTCD Section 1A.11 and A Policy on Geometric Design of Highways and Streets.

Option. An island may be designated by curbs, pavement edges, pavement markings, channelizing devices or other devices.

620.8.2 Approach-End Treatment (MUTCD Section 3I.02)

Guidance. The ends of islands first approached by traffic should be preceded by diverging longitudinal pavement markings on the roadway surface, to guide vehicles into desired paths of travel along the island edge.

Standard. Channelizing devices, when used in advance of islands having raised curbs, shall not be placed in such a manner as to constitute an unexpected obstacle.

Option. Pavement markings may be used with raised bars to better designate the island area.

620.8.3 Island Marking Application (MUTCD Section 3I.03)

Standard. Markings, as related to islands, shall consist only of pavement and curb markings, channelizing devices and delineators.

Option. Pavement markings as described in EPG 620.2.10 Approach Markings for Obstructions for the approach to an obstruction may be omitted on the approach to a particular island based on engineering judgment.

620.8.4 Island Marking Colors (MUTCD Section 3I.04)

Guidance. Islands outlined by curbs or pavement markings should be marked with retroreflective white or yellow material as determined by the direction or directions of travel they separate (see EPG 620.1.5 Colors).

Island curbs with non-mountable curbs at least 6 in. tall shall be marked with retroreflective markings or delineators.

The retroreflective area should be of sufficient length to denote the general alignment of the edge of the island along which vehicles travel, including the approach end, when viewed from the approach to the island.

Option. On long islands, curb retroreflection may be discontinued so that it does not extend for the entire length of the curb, especially if the island is illuminated or marked with delineators or edgelines.

An island with mountable curbs less than 3 in. tall may be marked with retroreflective markings or delineators.

620.8.5 Island Delineation (MUTCD Section 3I.05)

Standard. Delineators installed on islands shall be the same colors as the related edge lines except that, when facing wrong-way traffic, they shall be red (see EPG 620.5.3 Delineator Application).

Each roadway through an intersection shall be considered separately in positioning delineators to assure maximum effectiveness.

Option. Retroreflective or internally illuminated raised pavement markers of the appropriate color may be placed on the pavement in front of the curb and/or on the top of curbed approach ends of raised medians and curbs of islands, as a supplement to or as a substitute for retroreflective curb markings.

620.8.6 Pedestrian Islands and Medians (MUTCD Section 3I.06)

Support. Raised islands or medians of sufficient width that are placed in the center area of a street or highway can serve as a place of refuge for pedestrians who are attempting to cross at a midblock or intersection location. Center islands or medians allow pedestrians to find an adequate gap in one direction of traffic at a time, as the pedestrians are able to stop, if necessary, in the center island or median area and wait for an adequate gap in the other direction of traffic before crossing the second half of the street or highway. The minimum widths for accessible refuge islands and for design and placement of detectable warning surfaces are provided in the Americans with Disabilities Act Accessibility Guidelines for Buildings and Facilities (ADAAG) (see MUTCD Section 1A.11).

Fig. 620.8.6, Markings for Islands Painted and Raised