M22-01. 20 Design Manual
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- Điều hướng trang này:
- Highway Design Speed (mph) Ramp Design Speed (mph) 0 15 20 25 30 35
- Grade Upgrade Downgrade
- Chapter 1360 Interchanges WSDOT Design Manual M 22-01.20 Page 1360-17 September 2021
| Chapter 1360
Interchanges WSDOT Design Manual M 22-01.20 Page 1360-16 September 2021 Exhibit 1360-11 Deceleration Lane Length Edge of through lane Off-ram p First point at each ramp design speed 12 ft Deceleratio n lane A Edge of through lane Off-ra mp First point at each ramp design speed 12 ft Decelera tion lane A Tapered Off-Connection Parallel Off-Connection Highway Design Speed (mph) Ramp Design Speed (mph) 0 15 20 25 30 35 40 45 50 60 70 30 235 200 170 140 35 280 250 210 185 150 40 320 295 265 235 185 155 45 385 350 325 295 250 220 155 50 435 405 385 355 315 285 225 175 55 480 455 440 410 380 350 285 235 180 60 530 500 480 460 430 405 350 300 240 65 570 540 520 500 470 440 390 340 280 185 70 615 590 570 550 520 490 440 390 340 240 80 735 710 690 670 640 610 555 510 465 360 265 Minimum Deceleration Lane Length (ft) Grade Upgrade Downgrade 3% to less than 5% 0.9 1.2 5% or more 0.8 1.35 Adjustment Factors for Grades Greater Than 3% Note: Lane widths are shown for illustrative purposes. Determine lane widths based on Exhibit 1360-6. Chapter 1360 Interchanges WSDOT Design Manual M 22-01.20 Page 1360-17 September 2021 1360.04(5)(b) Gores Gores (see Exhibit 1360-12 and Exhibit 1360-13) are decision points. Design them to be clearly seen and understood by approaching drivers. In a series of interchanges along a freeway, it is desirable that the gores be uniform in size, shape, and appearance. The paved area between the physical nose and the gore nose is the reserve area. It is reserved for the installation of an impact attenuator. The minimum length of the reserve area is controlled by the design speed of the main line (see Exhibit 1360-12 and Exhibit 1360-13). In addition to striping, raised pavement marker rumble strips may be placed for additional warning and delineation at gores. (See the Standard Plans for striping and rumble strip details.) Keep the unpaved area beyond the gore nose as free of obstructions as possible to provide a clear recovery area. Grade this unpaved area as nearly level with the roadways as possible. Avoid placing obstructions such as heavy sign supports, luminaire poles, and structure supports in the gore area. When an obstruction is placed in a gore area, provide an impact attenuator (see Chapter 1620) and barrier (see Chapter 1610). Place the beginning of the attenuator as far back in the reserve area as possible, desirably after the gore nose. tải về 1.86 Mb. Chia sẻ với bạn bè của bạn:
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