at-grade junction where two or more roads or streets meet or cross. THIS AREA IS DESIGNATED FOR THE VEHICLES TO TURN TO Different Direction. VEHICLES MOVING IN DIFFERENT DIRECTION WANT TO OCCUPY SAME SPACE AT SAME TIME.

1. Introduction TO INTERSECTION
AT-GRADE JUNCTION WHERE TWO OR MORE ROADS OR STREETS MEET OR CROSS.
THIS AREA IS DESIGNATED FOR THE VEHICLES TO TURN TO DIFFERENT DIRECTION.
VEHICLES MOVING IN DIFFERENT DIRECTION WANT TO OCCUPY SAME SPACE AT SAME
TIME.

2. HISTORY

3. Development of modern roundabouts
Widespread use of the modern roundabout began when the UK's Transport Research
Laboratory during the 1960s.
Frank Blackmore led the development of the "priority rule" and subsequently invented the
mini-roundabout to overcome capacity and safety limitations.
In 1966, the United Kingdom adopted a rule at all circular junctions that required entering
traffic to give way to circulating traffic.
A Transportation Research Board guide reports that the modern roundabout represents a
significant improvement, in terms of both operations and safety.
 when compared with older rotaries and traffic circles. The design became mandatory in
the United Kingdom for all new roundabouts in November 1966.

4. SPREAD OF MODERN ROUNDABOUTS
 The modern roundabout spread to France and Norway in the 1970s.
 In 1991, France was building 1,000 roundabouts every year.
 As modern roundabouts rose in popularity in the 1980s
As of December 2015 there are about 4800 of these modern roundabouts in the United
States.
As of the beginning of the twenty-first century, roundabouts were in widespread use in Europe
 In 2019 France had more than 50,000 roundabouts.
While there are around 25,000 in the United Kingdom.

5. METHODOLOGY
The first phase of this study involved the selection of a suitable location.
We selected the Shahabad Gate intersection for its convenience in
collecting geographic data and the intersection plays a significant role In
Rampur City.
 Throughout the second phase, geographic and vehicular data of the
intersection were collected.
 In the third phase, after data collection the data will be analyzed to
determine the capacity of each entry lane, entry flow rate, circulating
and existing flow rate to.
As a final product of this study, we will convert the existing intersection to
roundabout and will present its possible benefits for sustainable
transportation.

6. TYPES OF INTERSECTION
•SIGNALIZGED
 INSTALLED AT MAJOR ROADS WITH TRAFFIC SIGNAL.
INVOLVED SEVERAL APPROACH LANES ON EACH LEG.
PROVIDE SPACE TO SUPPORT CYCLING TRANSPORT.
•UNSIGNALIZED
APPROACHES IS NOT CONTROLLED BY A REGULATORY SIGN.
USUALLY LIMITED TO VERY LOW VOLUME AND RESIDENTIAL AREAS.

7. MAJOR INTERCHANGES
Underpass
Overpass
Trumpet interchange
Diamond interchange
Cloverleaf interchange
Partial cloverleaf interchange
Directional interchange
Bridged interchange

8. UNDERPASS
• An underpass or a tunnel is an underground passageway, completely enclosed
except for openings for ingress, commonly at each end.
• A tunnel maybe for foot or vehicular road traffic, for rail traffic.

9. OVERPASS
An overpass also known as a flyover, is a bridge, road, railway or similar
structure that crosses over another road or railway.
A pedestrian overpass allows pedestrians safe crossing over busy roads
without impacting traffic.

10. TRUMPET INTERCHANGES
Trumpet interchanges have been used where one highway terminates at
another highway.
The principal advantages are low construction cost and are useful for
highways as well as toll roads.

11. ADVANTAGES OF ROTARY
 Traffic flow is regulated to only one direction of movement, thus eliminating
severe conflicts between crossing movements.
 All the vehicles entering the rotary are gently forced to reduce the speed
and continue to move at slower speed.
 Because of lower speed accidents and their severity are much less in
rotaries.
 Rotaries are self governing and do not need practically any control by
police or traffic signals.

12. DISADVANTAGES OF ROTARY
All the vehicles are forced to slow down and negotiate the intersection.
 Even when there is relatively low traffic, the vehicles are forced to reduce
their speed.
 Rotaries require large area of relatively at land making them costly at
urban areas.
 The vehicles do not usually stop at a rotary. They accelerate and exit the
rotary at relatively high speed.
 Therefore, they are not suitable when there are high pedestrian movements.

13. GUIDELINES FOR THE SELECTION
OF ROTARIES
• Rotaries are not suitable for every location. There are few guidelines that
help in deciding the suitability of a rotary
 Rotaries are suitable when the traffic entering from all the four approaches
are relatively equal.
 A total volume of about 3000 vehicles per hour can be considered as the
upper limiting case and a volume of 500 vehicles per hour is the lower limit.
 A rotary is very beneficial when the proportion of the right-turn traffic is
very high.
 Rotaries are suitable when there are more than four approaches.
 Rotaries are ideally suited if the intersection geometry is complex.

14. •Thank you!!!!