9.3.4.4 Arterials (or Urban Streets)

The LOS thresholds for urban arterial segments are based on travel speed of the vehicles traveling through the segment. HCM-based (mesoscopic) analyses are applicable for arterial and collector street segments with a length of two miles or less. If a segment is longer than two miles between boundary intersections, it is recommended that it is treated as a highway and the intersections are studied individually. If the segment being studied has intersections along its length, the speed and travel times of vehicles is largely dependent on intersection delay. Supplemental information with
example
applications is found in HCM 7th Edition Chapter 29 (Urban Street Facilities: Supplemental) and Chapter 30 (Urban Street Segments: Supplemental). shows the LOS criteria for urban arterial segments.
Table 9-12: HCM’s LOS Criteria: Motorized Vehicle Mode (On Urban Streets ≤ 2 miles)
LOS
Travel Speed Threshold by Base Free-Flow Speed (mi/h)
Volume-To-Capacity Ratio
a
55
50
45
40
35
30
25
A
>44
>40
>36
>32
>28
>24
>20
≤1.0
B
>37
>34
>30
>27
>23
>20
>17
C
>28
>25
>23
>20
>18
>15
>13
D
>22
>20
>18
>16
>14
>12
>10
E
>17
>15
>14
>12
>11
>9
>8
F
≤17
≤15
≤14
≤12
≤11
≤9
≤8
F
Any
>1.0
Note:
a
Volume-to-capacity ratio of through movement at downstream boundary intersection.