L=(WS²)/60 for 40MPH or less, L=WS for 45MPH or more - Formula for Min. taper length The off peak 85th percentile. Which is the speed at or below which 85% of vehicles travel operating speed in free flow conditions - speed used in formulas should be 125' - Distance of L for 25 MPH with 12' Lane width 245' - Distance of L for 35 MPH with 12' Lane width 540' - Distance of L for 45 MPH with 12' Lane width 660' - Distance of L for 55 MPH with 12' Lane width 780' - Distance of L for 65 MPH 12' Lane width L Minimum - Merging Taper Length 1/2 L Minimum - Shifting Taper Length 1/3 L Minimum - Shoulder Taper Length 50'-100' regardless of speed 6 devices 10'-20' apart - One-Lane, Two-Way Taper (Flagger taper) Length and number of devices 50'-100' per lane - Downstream taper Length 2L - Tangent distance (between tapers) 1/2L - Tangent distance before shifting taper Buffer Space Work Space Traffic Space - Activity Area Sub-components (3) Recovery Area for errant vehicles: Forgiving design This study source was downloaded by 100000886958468 from CourseHero.com on 06-18-2024 14:42:02 GMT -05:00 https://www.coursehero.com/file/226586731/uuuidocx/ Protects workers and Motorists Always completely empty or clear No vehicles, truck-mounted attenuator, equipment, or materials STRONGLY RECOMMENDED: unless there is a documented reason not to - Longitudinal Buffer Space Where road users are returned to their normal path extends from the downstream end of the work area to the last device such as end work zone sign May contain: end work zone sign: usually 500' past last device downstream taper = 50'-100' per lane - Termination Area is: can contain: (2) 100' - Recommended Advanced Warning Sign Spaceing: Urban (low speed) 350' - Recommended Advanced Warning Sign Spaceing: urban (high speed) 500' - Recommended Advanced Warning Sign Spaceing: Rural 1000', 1500', and 2640' - Recommended Advanced Warning Sign Spaceing: freeways and expressways (3) 1 Mile 50% shoulder at beginning of taper if possible, if not, as close to beginning as possible inside taper. - Arrow board visibility distance by design: night time dimming: location: taper: not to exceed distance in feet = to posted speed limit tangent: distance = double posted speed limit - device spacing taper: tangent: A: Low intensity flashing B: High-intensity flashing C: Steady Burn D: 360° steady burn - Warning lights types: Type A: Type B: Type C: Type D: Uses for portable changeable message sign PCMS - speed drops significant delays adverse conditions advance notice of closures advance notice of road changes reinforce static signage