Researchers rely on many specific definitions to describe the performance of
traffic operation systems.
The clear understanding of such terminology is an important element is studying
two-way stop-controlled (TWSC) traffic operation system characteristics; defined
as: One of the uncontrolled intersections with stop control on the minor street
shown in Fig. 1.
Figure 1:
Two way stop controlled intersection
![\begin{figure}
\centerline{\epsfig{file=qfUnCtrlTwoWayStop.eps,width=8cm}}
% (source [5])}
\end{figure}](img1.png) |
At TWSC intersections, the stop-controlled approaches are referred to as the
minor street approaches; the intersection approaches that are not controlled by
stop signs are referred to as the major street approaches.
A three-leg intersection is considered to be a standard type of TWSC
intersection if the single minor street approach is controlled by a stop sign.
Three-leg intersections where two of the three approaches are controlled by stop
signs are a special form of uncontrolled intersection control.
TWSC intersections assign the right-of-way among conflicting traffic streams
according to the following hierarchy:
- The major street through and right-turning movements are the
highest-priority movements at a TWSC intersection.
This movements shown Fig. 2 are 2, 3, 5, 6, 15 and 16.
- Vehicles turning left from the major street onto the minor
street yield only to conflicting major street through and right-turning
vehicles.
All other conflicting movements yield to these major street left-turning
movements.
The movements on this rank are 1, 4, 13, 14, 9 and 12.
- Minor Street through vehicles yield to all conflicting major
street through, right-turning, and left-turning movements.
The movements on this rank are 8 and 11.
- Minor Street left-turning vehicles yield to all conflicting
major street through, right-turning, and left-turning vehicles and to all
conflicting minor street through and right-turning vehicles.
The movements on this rank are 7 and 10.
Figure 2:
Traffic flow stream in two way stop controlled intersection
![\begin{figure}
\centerline{\epsfig{file=qfUnCtrlTrafficFlow.eps,width=8cm}}
% source[1]}
\end{figure}](img2.png) |
All-way-stop-controlled intersection (AWSC) are mostly used approaching from
all directions and is required to stop before proceeding through the
intersection as shown in Fig. 3.
An all-way stop may have multiple approaches and may be marked with a
supplemental plate stating the number of approaches.
The analysis of AWSC intersection is easier because all users must stop.
In this type of intersection the critical entity of the capacity is the average
intersection departure head way.
Secondary parameters are the number of cross lanes, turning percentages, and the
distribution volume on each approach.
The first step for the analysis of capacity is select approach called subject
approach the approach opposite to subject approach is opposing approach, and the
approach on the side of the subject approach is are called conflicting approach.
AWSC intersections require every vehicle to stop at the intersection before
proceeding.
Since each driver must stop, the judgment as to whether to proceed into the
intersection is a function of traffic conditions on the other approaches.
If no traffic is present on the other approaches, a driver can proceed
immediately after the stop is made.
If there is traffic on one or more of the other approaches, a driver proceeds
only after determining that there are no vehicles currently in the intersection
and that it is the driver’s turn to proceed.
Figure 3:
All way stop controlled intersection
![\begin{figure}
\centerline{\epsfig{file=qfUnCtrlAllWayStop.eps,width=8cm}}
% (source [5])}
\end{figure}](img3.png) |
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