Create alignment widenings

00:04

We're going to add some widening now to the left offset alignment.

00:07

Widening can be used to create lay bys and parking areas or to add widening lanes,

00:12

select the offset alignment. And on the ribbon choose add widening

00:17

on the command line.

00:18

It's asking if you want to create a new alignment or to add to the existing one select.

00:23

Yes,

00:25

we often use a new alignment for lay bys where

00:27

we want to maintain a cross fall to the channel line

00:30

and have a positive grade to the back of the lay by

00:35

set the start station for the widening to 1250

00:39

and for the end station

00:41

enter 1500

00:46

the widening offset will be 24 ft as measured from the center line,

00:54

choose the side left

00:56

and the offset parameters, dialogue would be called up.

01:00

You can change the offset

01:02

the start and end stations

01:05

or you can enter a region length.

01:11

You can change the transition parameters at entry and exit

01:17

for the transition parameters.

01:20

The transition type controls the geometry of the alignment at the transition.

01:25

If you set the transition type to linear,

01:27

you can choose the taper input type of by length or by taper ratio.

01:33

If you set the transition type to one including curves,

01:36

you get options to modify the curve radii,

01:41

try editing the curve radii

01:43

to see the changes on the screen.

01:49

Review. The other options for different transition types,

01:54

both transitions should be set to linear

01:57

by length

01:59

with the transition length of 100

02:04

changes to the widening are applied immediately. There's no option to save them.

02:10

You can also create widening to an offset alignment, graphically

02:15

make sure dynamic input is turned on for these edits

02:21

slip. The right hand offset alignment,

02:24

click the plus symbol to create a new widening region.

02:27

It will automatically widen it out.

02:31

Use the diamond grip to drag the transition to line up with the opposite lay by

02:38

press escape to clear your selection and then select the offset again.

02:42

Now you'll see two plus grips one for each region

02:46

split the right hand region. Again,

02:50

use the diamond grip to move the new widened region into position.

02:56

Use the arrow grip for the third region to move

02:58

the offset back in type 12 as the widening value.

03:05

Now select the circle grip on the transition

03:08

and then use the smaller circle grips

03:11

to change the length of the transition.

03:15

Adjust the position of the transitions using the diamond grips.

03:21

Now, if you select the arrow group in the central region

03:25

and type 12, as the offset,

03:28

it will reset the widening

03:30

back into a single item again,