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i <br />i <br />Location <br />i <br />TURN LANE DESIGN CHECKLIST (PAGE 1 OF 2) <br />STEP 1 — DATA GATHERING <br />State Roadway: Intersection: - <br />❑ Left Turn Lane Design for Approach: N / S / E / W <br />!9. Right Turn Lane Design for Approach: N / S law <br />Vehicle Speed Choose one. Shown in order of preference - <br />Page B-zDesign Speed: 4� mph 14r ¢� �' <br />❑ 85th Percentile Speed: mph <br />Forecast Traffic <br />Volumes <br />Page B-3 <br />i <br />❑ Statewide_ Average Speed: <br />Choose one. Shown in order of preference. <br />mph (page B-2, Figure B-1) <br />Design Year Volumes (provided by District/Central <br />Office Planning Staff) 2fl I v <br />❑ Historic Volumes (existing volumes extrapolated to <br />estimate 20 year forecast volumes) <br />j ❑ 20-Year Multiplier (documented by State Aid and found <br />at the following website under County Reference Data: <br />i http:!iwAfw dot.state.mn us/stateaid/sa_csah.html <br />Turning Volumes: see graphic at right, also note the <br />number of lanes for each movement. <br />Daily Volumes <br />Heavy <br />Commercial <br />Page 8-5- <br />Grade <br />Page 8-5 <br />Seasonal <br />Variations <br />17 7„ 3 r <br />Roadway <br />Geometry and <br />Corridor <br />Characteristics <br />?age 8-6 <br />Determine <br />Facility Type <br />Page B-3 <br />Intersection <br />Control <br />Page 3-9 <br />7 7? <br />1 <br />'T <br />Major Street Daily Traffic Volumes: vehicles per day <br />Minor Street Daily Traffic Volumes: ("s3C vehicles per day <br />Percent Heavy Vehicle: I % (If percentage of heavy commercial is high special consideration should <br />be taken in Step 4 for deceleration and storage length of turn lane) <br />❑ Upgrade ❑ Downgrade <br />Grade of approach: _ % (If greater than 3%, apply deceleration adjustment in Step 4) l <br />Is there a large seasonal variation within the corridor (recreational routes, primary farm to market routes, etc)? If <br />yes, consider the variation and potential increase in traffic volumes during peak periods. Is it enough of an <br />increase to change the design? ❑ Yes, adjust traffic volumes Wo <br />Is the intersection located on a horizontal curve? If yes, adjust taper in Step 4. (See Page B-17 and Table B-8) <br />❑ Yes, on horizontal curve *c No <br />Are there adjacent intersections that may influence the turn lane design? If yes, consider adjustments to the turn <br />lane design to better accommodate the constrained conditions. (See Pages B-23 and 24) <br />Yes, constrained location ❑ No <br />STEP 2 — DETERMINE FACILITY TYPE <br />Rural vs. Urban (based on Access Management Category Assignments: <br />Urban ❑ Rural <br />Expressway vs. Conventional (determined by Mn/DOT Office of Traffic, Safety and Technology) <br />❑ Expressway "Conventional <br />❑ Signalized: sec cycle length 'K Unsignalized ❑ Future Signal? (see Figure B-3) <br />Development of Turn Lane Design Guidelines <br />