Star Sign up now to gain access to all the features of this website. NEW — access is now open to ALL USERS! — Already registered? Please log in.

Geometry of weaving segments

Alexandre Hering Coelho
Universidade Federal de Santa Catarina
Geometry of weaving segments was posted on May 16th, 2018 at 10:21 AM EDT
regarding Chapter 12: Freeway Weaving Segments

Good morning everyone.

What would be the correct determination of the geometric characteristics of the weaving segment illustrated in this figure http://ahcoelho.net/downloads/temp/question_weaving_geometric.pdf, involving LCfr, LCrf and Nwl? Should the segment considered one or two-sided? Could exists weaving segments with LCfr or LCrf greater than 1? On the figure I tried to classify the lanes for the determination of Nwl, considering one-sided. The lanes 4 and 5 are merging on the segment, becoming one lane to classify for Nwl. Coming from the freeway this lane counts (0 lane changes required), but coming from the ramp it doesn't (2 lane changes required). In this situation, what prevails for the classification of this lane?

Thank you for ant comment.

Joseph Fazio
RE: Geometry of weaving segments was posted on May 16th, 2018 at 11:30 AM EDT

In my opinion, the diagram indicates a one-sided weave because on p. 13-5 6th Ed. HCM the definition of a two-sided weave is "one in which at least one weaving maneuver requires three or more lane changes to be completed successfully or in which a single-lane on-ramp is closely followed by a single-lane off-ramp on the opposite side of the freeway."

In the diagram, there are no single lane ramps, and LC_FR = 0 lc and LC_RF = 2 lc. Thus, the weave segment is not two-sided.

On p.13-7, NWL is "number of lanes from which a weaving maneuver may be completed with one lane change or no lane changes."

In the diagram, Lane 1 weavers must make 2 lc, Lane 2 weavers must make 1 lc, Lane 3 makes 0 lc, Lane 4 makes 0 lc, Lane 5 weavers makes 2 lc, and Lane 6 makes 3 lc. Thus, NWL = 3 ln.

(Edited May 16th, 2018 at 11:32 AM EDT)

Sign in to add a reply. Don't have an account? No problem, sign up for free.