Civil Engineering Reference
In-Depth Information
Fig. 15.1
Factors impacting on congestion delay from a roadway incident
(t
3
-
t
2
) = time elapsed after the incident is reported and when the incident team
arrives;
(t
4
-
t
3
) = time needed to restore capacity (all lanes reopened);
(t
5
-
t
0
) = duration of delay if traf
c demand continues unabated;
(t
6
-
t
0
) = duration of delay if traf
c demand is reduced;
(t
7
-
t
4
) = delay time to last vehicle in longest platoon (Q
max
) before it resumes
normal speed;
(t
4
-
t
8
) = maximum delay time before capacity is restored;
t
0
) = time interval when roadway operates at reduced capacity.
The impact of an incident on delay depends upon:
(t
4
-
The severity of the incident (number of lanes blocked) and the volume of traf
c
on the roadway at the time of the incident;
The time the incident is detected;
The time it is reported to the responding agency;
The agency response time;
The time elapsed before the roadway capacity is completely restored;
The volume of upstream traf
c approaching the incident location.
