Propose fit alternatives to existing Networks (5:54 min)

00:00

INSTRUCTOR: Hi there.

00:01

In this video, we will be checking and validating

00:04

potential alternatives to the existing network of our road

00:07

and highway project.

00:09

This is where we are on the overall view

00:11

of the analysis in civil engineering learning path.

00:18

Before proposing new alternatives,

00:19

we will align the model that we will

00:21

use as the base for the rest of the proposals, PO1A.

00:26

To do so, we will remove all the sources

00:28

that are not relevant to our goal, which means buildings,

00:32

city furniture, and railways, leaving the ground imagery,

00:35

the roads, and the terrain.

00:38

Cleaning out the PO1A model will allow

00:40

us to regenerate the proposals quicker,

00:42

making it easy to undo or redo our model.

00:53

Let's now switch on the TSA, focus on the TSA4,

00:57

and run the long morning simulation.

00:60

We can observe that the level of service

01:02

is not unmissable for the delay threshold allowed

01:04

by the local authorities.

01:07

All intersections have delays above 35 seconds.

01:11

This is the East intersection which

01:13

crosses the two freeways within the area,

01:15

and it has an average delay of 81 seconds.

01:19

The South intersection is the only one

01:21

that is not signalized, meaning it does not have lights

01:24

controlling the intersection.

01:26

Having into account that the initial information,

01:29

the intention of the alternatives to be proposed

01:31

is to reach a good level of service

01:33

with delays below 35 seconds.

01:36

This is the first alternative proposed, PO1A roundabout.

01:42

As you see, the West intersection

01:44

which was signalized has been replaced by a roundabout.

01:48

After running the long morning simulation

01:50

with the same demands and TSA details

01:53

that the ones used for the original PO1 proposal,

01:57

we can observe that far from reducing

01:59

the delays in the network, we have increased them by 10.

02:04

The current arrangement starts collapsing

02:06

the East intersection, forming a queue

02:09

towards the newly installed roundabout that

02:12

ends up collapsing the roundabout as well.

02:15

Once the roundabout is collapsed,

02:16

the nearby demand zones are reached by the queues,

02:20

and we can spot failures in the simulation

02:22

with cars overlapping or moving in a strange way.

02:29

Straight away, without a single doubt,

02:31

we can obviously state that the PO1A roundabout proposal is not

02:36

a feasible alternative.

02:44

The next alternative proposed is called PO1A roundabout 1.

02:49

The new proposal substitutes designalized East intersection

02:53

with another roundabout, keeping the West roundabout

02:57

from the previous proposal.

02:59

After running the long morning simulation

03:01

on our traffic simulation asset card

03:04

the simulation results displayed on the canvas

03:07

show acceptable delays and levels

03:09

of service on the TSA full network analysis.

03:13

In order to validate our findings,

03:15

let's make sure that the demand matrix data is the same on this

03:19

and the original PO1 proposal.

03:32

Now that the validation has been confirmed,

03:35

let's try to find a way to polish our proposal winner,

03:38

PO1 roundabout 1.

03:42

The intention of the PO1 roundabout proposal

03:45

is to reduce risks on this South unsignalized intersection.

03:52

Bearing in mind the arrangement you can see,

03:54

the intention is to add two auxiliary lanes--

03:58

that has been done already--

03:60

then, force the second lane from the exterior

04:03

of the road 3 North a mandatory right turn into road 9.

04:08

Then force the other two lanes of the road

04:10

to the North to only go straight because that combined will

04:15

allow it to have a freeway or a yield control to the road

04:25

To start, lets force the second lane from the exterior through

04:34

That's done.

04:35

Now we're going to open tab and check the specific and detailed

04:40

behavior of each lane.

04:44

So far, everything looks fine.

04:46

The arrows are pointing to the correct direction,

04:48

but let's check the intersection.

04:51

To start, the road

04:54

controlled by a stop sign.

04:56

Given that the two internal street

04:58

lanes of the road 3 North are splitting in 4

05:01

to the intersection, we want amend the behavior

05:04

to allow the freeway proposed for the lanes coming

05:07

from the road number 9.

05:09

Once this is done, we can enable the freeway for the road

05:15

sign for the lane turning left.

05:24

After syncing to the cloud from tap, back in Infoworks,

05:29

we can run the simulation again and check how it looks like.