HCM Chapter 13

Freeway Weaving Segments

Estimate capacity, weaving and nonweaving speeds, density, and level of service for a freeway weaving segment.

The compute engine reproduces the published HCM worked examples for this chapter under both editions. The 7th Edition and Edition 7.1 are different models. The same segment can land a full LOS letter apart between them, and weaving LOS F begins at 35 rather than 43 pc/mi/ln under 7.1, so results are only comparable within one edition. Please report discrepancies on GitHub.

Configuration

Weaving segment geometry and lane-changing configuration.

Edition 7.1 replaces this chapter's methodology; the editions report different speeds, capacities, and LOS.

ft

Distance between the barrier markings of the entry and exit gores.

2 or 3 for one-sided segments, 0 for two-sided segments.

lc/veh
lc/veh
lc/veh
int/mi

Hover a movement to trace it through the segment. The picture follows the inputs.

L_S

Traffic

Component demand volumes and traffic-stream characteristics.

veh/h
veh/h
veh/h
veh/h
mph
%
pc/h/ln

Capacity of an equivalent basic freeway segment at the same FFS.

Use 1.00 for base conditions.

Use 1.00 for base conditions.

Outputs

Results populate after pressing Calculate.

Weaving Flow Rate (pc/hr):
Nonweaving Flow Rate (pc/hr):
Total Flow Rate (pc/hr):
Volume Ratio:
Maximum Weaving Length (ft):
Operates as Weaving Segment:
Capacity (veh/hr):
Volume-to-Capacity Ratio:
Weaving Speed (mi/hr):
Nonweaving Speed (mi/hr):
Average Speed (mi/hr):
Density (pc/mi/ln):

Segment LOS: