9.3.4.2 Freeways

LOS for freeway facilities is based on the facility-wide average density expressed in pcpmpl. There are separate density thresholds for urban and rural locations. The LOS for an overall freeway facility is typically accompanied by the LOS for the individual segments. LOS for basic freeway segments, weaving segments, merge, and diverge segments are also based on density. The LOS thresholds apply to both urban and rural locations. The thresholds for weaving segments are higher than basic segments because drivers tolerate higher density in areas where lane-changing is expected. Supplemental information with
example
 applications are provided in HCM 7th Edition Chapter 25 (freeway facilities), Chapter 26 (freeway and highway segments), Chapter 27 (freeway weaving), and Chapter 28 (freeway merges and diverges). For LOS criteria of various freeway facilities see and .
Table 9-6: HCM’s LOS Criteria for Basic Freeway
LOS
Density (pc/mi/ln)
A
≤ 11
B
>11-18
C
>18-26
D
>26-35
E
>35-45
F
Demand exceeds capacity OR density > 45
Table 9-7: HCM’s LOS Criteria for Urban and Rural Freeway Facilities
LOS
Urban Freeway Facility Density (pc/mi/ln)
Rural Freeway Facility Density (pc/mi/ln)
A
≤11
≤6
B
>11-18
>6-14
C
>18-26
>14-22
D
>26-35
>22-29
E
>35-45
>29-39
F
>45 or any component section v/c ratio > 1.0
>39 or any component section v/c ratio > 1.0
Table 9-8: HCM’s LOS Criteria for Freeway Merge and Diverge Segments
LOS
Density (pc/mi/ln)
A
≤10
B
>10-20
C
>20-28
D
>28-35
E
>35
F
Demand exceeds capacity
Table 9-9: HCM’s LOS for Weaving Segments
LOS
Freeway Weaving Segments
Weaving Segments on Multilane Highways or Collector-Distributor Roads
A
0-10
0-12
B
>10-20
>12-24
C
>20-28
>24-32
D
>28-35
>32-36
E
>35-43
>36-40
F
>43, or demand exceeds capacity
>40, or demand exceeds capacity