Pavement Markings--Design and Typical Layout Details (2006) / Chapter Skim
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Pages 36-42
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From page 36... ...
Paragraph 6 of Section 3B.05 contains the following support: "Channelizing lines at entrance ramps as shown in Figure 3B-9 promote reasonably safe and efficient merging with the through traffic." Paragraph 9 of Section 3B.05 contains the following guidance: "For entrance ramps, a channelizing line should be placed along the side of the neutral area adjacent to the ramp lane." Paragraph 11 of Section 3B.05 contains the following option: "For entrance ramps with a tapered acceleration lane, lane line markings may be placed to extend the channelizing line, but not beyond a point where the tapered lane meets the near side of the through traffic lane as shown in Figure 3B-9." Paragraph 5 of Section 3B.05 contains the following support: "Channelizing lines at exit ramps as shown in Figure 3B-8 define the neutral area, direct exiting traffic at the proper angle for smooth divergence from the main lanes into the ramp, and reduce the probability of colliding with objects adjacent to the roadway." Paragraph 7 of Section 3B.05 contains the following standard: "For exit ramps, channelizing lines shall be placed along the sides of the neutral area adjacent to the through traffic lane and the ramp lane." This standard is universally followed. Paragraph 8 of Section 3B.05 contains the following option: "White chevron markings may be placed in the neutral area for special emphasis as shown in Figure 3B-8." Although this paragraph immediately follows a paragraph regarding exit ramps and although Figure 3B-9 does not mention the option of using chevrons in the paved gores for entrance ramps, there are no provisions in the MUTCD that 36 specifically prohibit the use of chevrons in the paved gores for entrance ramps.
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From page 37... ...
The design standards consistently show the channelizing line on the left-hand side of an entrance ramp extending to the downstream end of the paved gore (where the ramp and the mainline roadway become adjacent to one another) when a parallel acceleration lane is used.
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From page 38... ...
The design standards consistently show the channelizing line extension on the left-hand side of an entrance ramp extending to the downstream end of the paved gore (where the left-hand side of the ramp reaches the edge of the mainline roadway) when a tapered acceleration lane is used.
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From page 39... ...
The design standards consistently show that the use of a channelizing line on the right-hand side of the mainline roadway is required for exit ramps. Upstream End of Channelizing Lines for Exit Ramps with Tapered Deceleration Lanes (44 agencies)
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From page 40... ...
The following points (measured downstream from the downstream end of the paved gore) are explicitly specified in the design standards for the downstream end of the channelizing line on the right-hand side of the mainline roadway: AL, CA, FL, GA, IN, IA, MA, MI, MN, MO, MT, NV, NY, NC, OK, OR, UT, VT, WA, WY, PR -- 0 ft ND -- 0 ft for parallel deceleration lanes and 200 ft from the upstream end of the paved gore for tapered deceleration lanes NH -- 5 ft CT -- 20 ft HI -- 40 ft DE -- less than 50 ft (the point on the right edge line where a perpendicular line would line up with the downstream end of the gore striping on the ramp)
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From page 41... ...
show that the use of a dotted line to extend the right edge line of the mainline roadway to the upstream end of the paved gore of exit ramps with tapered deceleration lanes is optional. The design standards for 11 agencies (CA, FL, LA, MD, MN, MO, NE, NV, SC, VA, and WA)
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From page 42... ...
The design standards for Alabama show that for exit ramps with a tapered deceleration lane and a parallel recovery lane, diagonal 12-in.-wide lines at 20-ft intervals in urban areas and 30- to 40-ft intervals in rural areas are used within the right shoulder of the parallel recovery lane for the recovery 42 lane's entire length and within the left shoulder of the ramp for a distance of 80 ft beyond the point where the paved portion of the gore ends. For exit ramps with a recovery area, diagonal 12-in.-wide lines at 20-ft intervals in urban areas and 30- to 40-ft intervals in rural areas are used within the right shoulder of the mainline roadway for a distance of at least 320 ft beyond the point where the paved portion of the gore ends and within the left shoulder of the ramp for a distance of 80 ft beyond the point where the paved portion of the gore ends.
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