M22-01. 20 Design Manual
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- Chapter 1360 Interchanges WSDOT Design Manual M 22-01.20 Page 1360-27 September 2021
| Chapter 1360
Interchanges WSDOT Design Manual M 22-01.20 Page 1360-26 September 2021 Exhibit 1360-17 On-Connection: Two-Lane, Parallel L g =300 ft min [3] . PT of ramp curve [6] End of ramp stationing A [2] PCC of Ramp curve Acceleration lane L A [1] 300 ft min R=4 ft [4] 24 ft min Edge of shoulder Edge of through lane [7] . 90.0° [5 ] . 8 ft 10 ft Notes: [1] For acceleration lane length LA, see Exhibit 1360-10. [2] Point A is the point controlling the ramp design speed. [3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the main line. The transition curve may be replaced by a 50:1 taper with a minimum length of 300 ft. [4] Radius may be reduced when concrete barrier is placed between the ramp and main line. [5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths, see Exhibit 1360-6. [6] Ramp stationing may be extended to accommodate superelevation transition. [7] Added lane or 1,500-ft auxiliary lane plus 600-ft taper. General: For striping, see the Standard Plans . Chapter 1360 Interchanges WSDOT Design Manual M 22-01.20 Page 1360-27 September 2021 Exhibit 1360-18 On-Connection: Two-Lane, Tapered Notes: [1] For acceleration lane length LA, see Exhibit 1360-10. [2] Point A is the point controlling the ramp design speed. [3] A transition curve with a minimum radius of 3000 ft is desirable. The desirable length is 300 ft. When the main line is on a curve to the left, the transition may vary from a 3000-ft radius to tangent to the main line. [4] Radius may be reduced when concrete barrier is placed between the ramp and main line. [5] Lane and shoulder widths are shown for illustrative purposes. For ramp lane and shoulder widths, see Exhibit 1360-6. [6] Approximate angle to establish ramp alignment. [7] Added lane or 1,500-ft auxiliary lane plus 600-ft taper. General: For striping, see the Standard Plans |