Highway Engineering

Parameters:

m=capacity

r=ratio of actual flow to capacity =q/m

q =actual flow

C =1 for random arrivals and service patterns

C =0 for regular arrivals and service patterns

L 0 =queue length at start of time interval under consideration

t =time.

It is reasonable to set C equal to 1. Therefore, Equations 5.8, 5.9, 5.11 and 5.12

can be simplified as:

(5.16)

(5.17)

(5.18)

(5.19)

(5.20)

Q (5.21)

tL

t

=+ÊËÁ ˆ ̄ ̃

(^220)
m
r
m
PtL=¥-[]05 1()--() 0

1

. r 1
m

GL=+ 420 rmt

FtL=¥-[]05 1()rm-+ 0 1.

B=4 L() 0 +rmt

A= 1()-rmt+- 1 L 0

114 Highway Engineering

Example 5.2 – Computing capacities, queue lengths and delays at a

priority intersection

Figure 5.13 indicates a set of design reference flows for the evening peak hour

at a proposed urban-based priority intersection. All flows are in passenger

car units per hour.

175

B

550

150

75

750

125

C A

Figure 5.13Design reference flows at priority intersection.

Contd