2. Corridor:
A Corridor is a set of essentially parallel & competing
facilities & modes with cross – connectors that serve trips
between two designated points. It may contain rural
highway ,urban street ,pedestrian ,etc.
Corridor Traffic forecasting
Corridor Traffic Study
Count
Segment
Point
3. o Segment: Segments are stretches of a facility in which the traffic
demand and capacity conditions are relatively constant.
o Point: Points are locations at the beginning and end of each segment, at
which traffic enters, leaves, or crosses the facility.
o Freeway: A freeway is defined as a divided highway with full control of
access and having two uninterrupted flow or more lanes for the exclusive
use of traffic in each direction. All the access is through a ramp a separate
entrance or exit way to or from the Freeway.
4. o Segment Capacity :
Capacity is the maximum hourly flow rate, at which persons or
vehicles reasonably can be expected to traverse a point or a
uniform section, of a lane or roadway during a given time period,
under prevailing roadway, traffic and control conditions. But
sometimes the demand may exceed the capacity during peak
hours, which will bring Queue delay. Thus demand adjustment is
required and is done as follows: Adjusting for excess demand
from the capacity is necessary only if working with forecasted or
estimated demands rather than counted traffic. If the demand
exceeds the capacity at any point in time or space, then the
excess demand must be stored on the segment and carried over
to the following hour. The downstream demands are reduced by
the amount of excess demand stored on the segment. The
algorithm starts with the entry gate segments on the periphery of
the corridor and works inward until all segment demands have
been checked against their capacity.
5. o Corridor Identification Steps:
Step One: Data Collection & Review -1. Collect and review various background information.
2. Review existing plans and recommendations for the study area.
Step Two: Identify Issues & Planning Concepts -3. Identify planning process issues.
4. Visualize issues and identify alternative concepts.
5. Review and discuss background information, issues and concepts with
community.
6. o Corridor Identification steps..
Step Three: Develop & Choose Alternatives -6. Identify land use alternatives.
7. Present & review land use alternatives with community.
8. Evaluate alternatives.
9. Choose recommended alternative.
Step Four: Create Plan -10. Identify implementation priorities.
11. Review draft plan, recommended alternative, and implementation
with community.
12. Draft & adopt plan.
7. o Corridor Analysis :
Corridor analysis is the method of combining
point , segment & Facility analysis to estimate
the overall performance of multimodal corridor.
Mostly the performance measure of any
corridor are determined by calculating its
capacity ,the travel & queue delay in the
given section. Since this tool is required for
multi facility & multimodal transportation
system mostly it covers highway subsystem (
freeways,rural highways & urban streets) &
transit.
8. o
Queue Delay :
The queuing delay only the amount due to demand
exceeding capacity is computed for all segments. The
queuing delay is computed for each direction of each
segment and time period only when demand is greater
than Capacity.
o Free flow Travel time:
The segment free-flow traversal times are obtained by dividing the
length of the segment by the estimated free-flow speed (FFS).
9. Cordon Line Survey
Objective
To understand the present internal-external travel patterns
(Origin - Destination matrix) The survey supplements the
Home Visit Survey.
Methodology
Traffic Count Survey
Interview Survey (Roads, Railway, Airport)
10.
11. o Screen Line Survey :
o Objective
The estimated OD matrix from PT Survey will be verified by
comparing estimated demand on the selected links in the
traffic simulation with the counted traffic volume on the
screen line
o Methodology
Traffic Count (Hourly traffic volume by vehicle type by
direction, 24 hours and 16 hours)
12.
13. o Screen Line Analysis :
o Screen line analysis compare the results of trip
assignment with the traffic counts on roads. More
precisely, it is a process of comparing the directional
sum of ground count traffic volumes across a screen line
or a cordon line with the directional sum of the assigned
traffic volumes across the same screen line or corridor
line.
o
Screen line analysis is a useful tool for the calibration of
trip assignment models, & it can also be used for more
general purpose of calculating flows that cross a screen
line .
14. o Conclusion :
o Delay due to traffic congestion accounts 28.9%
(PHD/PHT) of the total number of travel.
o No any over saturation (i.e., no Queue delay). So that
the sub system is good.
o Though many vehicles are passing without stopping
there is operational failure (there are few vehicles
passing the section with stopping).