HCM Chapter 15

Two-Lane Highways

Estimate free-flow speed, follower density, average speed, and level of service for two-lane highway facilities, segment by segment.

Open in Builder Takes this form to the facility builder as a Chapter 15 fixture. That schema states the passing type, the grade and its class, and the subsegments a curve produced, so the builder recovers them as placed features.

Import

Optionally load a previously exported analysis.

Segments

Define the passing type and traffic characteristics of each segment.

#Passing TypeLengthGradePosted SpeedHoriz. CurvesDemand Vol.Opposing Vol.Vertical ClassPHF% Heavy Veh.
1
mi
%
mph
veh/h
veh/h
%

General Parameters

Facility-wide values and horizontal-curve subsegments.

ft
ft
/mi
%

Only applied when a Passing Lane segment is present.

Facility Layout

Visual sequence of the configured segments. Select one in either view to highlight its row. Expand to edit them here.

1 Not set
—

Outputs

Results populate after pressing Calculate.

Segment 1
Free-flow Speed (mi/hr):
Average Speed (mi/hr):
Percent followers in the
analysis direction (%):
Followers Density (followers/mi):
Segment LOS:

Facility LOS:

Facility Follower Density: