Civil Engineering Reference
In-Depth Information
Table 8.8
Level of service
criteria for signalized
intersections: automobile
mode
Control delay (s/vehicle)
LOS by Volume-to-
capacity ratio
a
≤
1.0
>1.0
≤
10
A
F
>10
-
20
B
F
>20
-
35
C
F
>35
55
D
F
-
80 E F
>80 F F
a
For approach-based and intersection wide assessments, LOS is
de
ned solely by control delay
Source
Reference [
17
], Highway Capacity Manual 2010, Volume
3, Chapter 18
>55
-
Table 8.9
Level of service
criteria for unsignalized
intersections: automobile
mode
Control delay (s/vehicle)
LOS bv volume-to-
capacitv ratio
v/c ≤
1.0
v/c
> 1.0
0
10
A
F
-
>10
-
15
B
F
>15
25
C
F
-
35 D F
>35
-
50 E F
>50 F F
The LOS criteria apply to each lane on a given approach and to
each approach on the minor street. LOS is not calculated for
major-street approaches or for the intersection as a whole
Source
Reference [
17
], Highway Capacity Manual 2010, Volume
3, Chapter 19
>25
-
Table 8.10
Level of service
criteria corresponding to
travel speed on city streets
Travel speed as
a percentage of base
free-flow speed (%)
LOS By critical
volume-to-capacity ratio
≤
1.0
>1.0
>85
A
F
>67
85
B
F
-
>50
67
C
F
-
>40
-
50
D
F
>30
40
E
F
-
30 F F
The critical volume-to-capacity ratio is based on consideration of
the through movement volume-to-capacity ratio at each boundary
intersection in the subject direction of travel. The critical volume-
to-capacity ratio is the largest ratio of those considered
Source
Reference [
17
], Highway Capacity Manual 2010, Exhibit
16.4
≤
