ECF Lane Tapers - ID Check Area Widening
This module calculates the taper lengths for tapering from an approach zone into an ID check area, and from an ID check area into a response zone. This considers a possible change in the number and width of lanes between these areas, as well as the presence of a guard booth.
Fill in the matrix for number of lanes and lane width in the approach zone, ID check area, and response zone. Additionally, enter the width of guard islands in the ID check area. Guard islands are assumed to be used between lanes, and not needed for the left-most lane since guards would utilize the median.
Design speed: Select the design speed. If it is not known, use either the 85th percentile travel speed or the posted speed limit plus up to 10 additional mph.
Widening can occur symmetrically from the middle or only to one direction. Check the appropriate box.
The approach zone taper length is the total length of the taper to transition from the approach zone to the ID check area.
The response zone taper length is the total length of the taper to transition from the ID check area to the response zone. Note that this calculation does not influence the location of active vehicle barriers and cannot be used for placement of active barriers.