Click for next page ( 64


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 63
At the upstream start of the full lane width of the ATL, place a lane configuration sign (side-mounted MUTCD R3-8 series sign) and add lane- use pavement markings to both the ATL and CTL lanes at this same point to provide lane-use confirmation for drivers. Place overhead lane configuration signs for both the ATL and CTL on the signal mast arm for the approach to provide additional confirmation of lane use for drivers. Step 4: Design the Downstream Full-Width Lane Segment of the ATL Similar to Step 3, this step identifies the signing and pavement markings for the downstream ATL segment: Place a 10-foot skip stripe with 30-foot breaks along the entire length of the downstream full-width lane. Provide a side-mounted "Right Lane Ends" W9-1 sign approximately 50 feet minimum from the crosswalk (extension of opposite stop bar). Place the "Lane Ends" W4-2 sign at a point halfway between the extension of the opposite stop bar and the end of the full-width lane segment, approximately 150 feet from the extension of the opposite stop bar. Note: Ensure a minimum distance of 100 feet between the W4-2 sign and the upstream "Right Lane Ends" W9-1 sign. Step 5: Design the Tie-ins at the Intersection Design the curb tie-ins on both the upstream and downstream sides of the intersection to connect the ATL to the principal arterial cross street, as described in the following bullets: Determine the appropriate design vehicle for the intersection based on local standards. In this example, the design vehicle is a WB-50. Place an appropriate radius for the curb return to connect the ATL to the cross street exit leg based on the WB-50 envelope. In this example, a 50- foot curb return radius is used. Place an appropriate radius for the curb return to connect the principal arterial approach to the ATL based on the WB-50 envelope. In this example, a 50-foot curb return radius is used. SUMMARY Exhibit 6-8 illustrates the result of the design process for the sample application of the one-CTL approach with a shared ATL. Remaining design steps for an ATL are similar to that of any full (continuous)-lane widening design process. They include developing plans for the vertical profile, drainage, and utility relocations (where necessary) and preparing final design plans, specifications, and a cost estimate for the ATL improvement. Page 64

OCR for page 63
Exhibit 6-8 Comparison of the Base Case to the Preferred Alternative Design Page 65