paper on traffic management

1. Application of Fluid Dynamics in Traffic
Management
(Mechanical Engineering)
Jaydeep S. Deshpande
S.E. Mechanical Engineering
PVG’s College of Engineering & Technology
Pune
jaydesh1@gmail.com
In this paper I am presenting possible use of Fluid Mechanics
principles in governing road traffic. Models based upon fluid flow
patterns show striking similarities with traffic flow. Flow around
streamlined bodies and bluff bodies can directly be linked to flow
around structures present on the roads. By modifying fluid flow
equations, obtained results can be directly implemented on current
traffic conditions. Under dynamic conditions an experiment carried
out at Nal Stop Chouk Signal, Karve Road, Pune shows the signal
timings required to avoid traffic jams and current signal timings
configured.
B. Boundary Layer
Keywords: In case of fluids, when fluid flow is initiated over a surface,
a boundary layer is generated along the surface of very small
I. INTRODUCTION thickness. This layer almost sticks to the surface and slows
Traffic conditions in big cities are getting worse with ever down adjacent layers of the fluid. Similar phenomenon is also
increasing number of vehicles. Major routes in the cities face observed in traffic flow. Vehicles moving along the
the problem of traffic jams, or slow moving traffic. Social boundaries get slower as they go closer to the boundary. They
festivals, progressions further worsen the situation by also slow down nearby vehicles, shows an observation.
obstructing the traffic flow. Flow of traffic can be visualized as Boundary layer separation in case of fluid produces wake
flow of any fluid in similar virtual environment, where region (region having lower pressure). Similar condition is
continuously moving vehicles considered as continuum. Same also obtained in traffic flow; an empty spot is created behind
theory can still be applicable in case of open roads by co-
relating it with open channel flow analogy. Validation was an obstruction around which the flow is taking place. Such
carried out at Nal Stop signal by calculating signal timings. spot can be termed as wake region in traffic flow.
In case of sharp edged objects, wake region is bigger, where
as in case of smooth bodies no or very small wake region is
II. ANALOGIES
created. So is observed in case of traffic flow, where no dead
A. Nozzle Effect. spot (no vehicle is present) is obtained in case of streamlined
flow of vehicles. Flow around obstruction often results into
Nozzles are most commonly used in rocket motors. Their
formation of dead spots, where no vehicle travels from. It is
Function is to increase velocity of the exhaust gases. Similar
Phenomenon is also observed in case of traffic flow. Moving unused space of the road, and it certainly can be utilized by
vehicles suddenly speed up as they find open channel ahead. proper measures as shown. Shaping the obstructions with no
Choking of flow increases vehicle density, and thus as they or very few edges ensures smoother flow of vehicles around it.
approach an opening for an open channel, vehicles move away And thus traffic jams or dead spots are avoided.
from each other and accelerate.

2. Vehicle Flow Rate- ‘Q’ vehicles/sec
Average Velocity of Vehicles- ‘V’ m/sec
k- Traffic Density
B. Equation
t=100k/Q;
Also Q=kV.
C. Observations
• Flow is not steady as in case of fluids, thus the
equations give approximate results.
• Psychological factor cannot be included while
formulating the equations.
• Unlike fluids, traffic flow can sometimes show random
directions, and cause malfunctioning of the system.
• During the peak hours, flow can be considered steady,
and thus the equation above very well holds up.
• Average velocity is considered to be 40kmph, though it
can vary in certain range, it does not alter the results
much.
• At 9AM. Flow rate is found to be 8-10 vehicles/sec at
about 50kmph. That gives k=13.89.
III. EXPERIMENT: DESIGNING SIGNAL SYSTEM
Same logic can be extended to signals while designing D. Results
appropriate signal timings and overall traffic system. An Sr. Time ‘Q’ ‘t’ ‘t’ Remark(signal
experiment was carried out to verify it. Several readings were calculated actual t)
taken at Nal Stop Signal. Vehicle flow readings were noted 1 8 AM 6-8 198 100 Can be reduced
down at SNDT junction. The vehicle flow rates at different 2 10 12- 106 100 Perfect
times were recorded. A traffic distance of 100 m. was defined
as traffic jam and to calculate the accurate signal timings to AM 15
avoid traffic jams is formulated. 3 7 PM 18- 73 100 Jam!
20
E. Conclusion
Tool of fluid mechanics can be effectively utilized to
establish a good traffic system. Instead of adapting to
technologies like GPS, which are costly, it is possible to
have a good traffic management just by modifying existing
structure with the help of this tool. Results obtained by the
theory speak for the real time situation observed and are
closely comparable.
REFERENCES
[1] Fluid Mechanics- Frank M White
[2] Fluid Mechanics- R.K.Bansal
The figure shows variation in traffic flow rate with time [3] ScienceDailywebsite-
during different hours of the day. http://www.sciencedaily.com/articles/t/traffic_engineering_(transportati
on).html
[4] ERCIM NEWS-http://ercim-news.ercim.eu/fluid-dynamic-approach-to-
A. Abbreviations and Acronyms traffic-flow-problems
Signal Time to Avoid Traffic Jam-‘t’ sec.