T-Intersection
Use this function to design a T-Intersection.
This function completely designs the T-Intersection/Y-Intersections including deflection islands.
The function can handle any type of intersection (skew intersection, intersection on horizontal curves, etc.).
The resulted T-Intersection is a 2D drawing.
Run the function from the following locations:
MOUS_ICO Toolbar: Intersection Design: T-Intersection
MOUS_ICO Menu: Road > Intersection Design > T-Intersection
The dialog has a graphic area, which displays the intersection indicating the different road arms (approach roads).
The intersection is classified as three different road arms A, B, and C.
For each road arm, median/deflection island and left/right turn lane can be designed.
The parameters of the elements such as median widths, extra lane widths, curve radii, curb, etc., are defined using separate buttons.
Notes:
Depending on the lane setup (left/right lane driving) selected, the function designs the intersection.
The explanation below is in accordance with right lane driving.
For right-hand driving setup, either Left turn lane or Traffic separator of road arm C is available to select.
Similarly, for the left lane driving setup, either Traffic separator or Right turn lane of road arm A is available to select.
Construction parameters
Dimensional parameters
Use this button to define the design vehicle and design speed for the intersection.
Select the design vehicle for the pull-down menu at the field Design vehicle.
Enter the design speed in km/h.
Lanes
Use this button to define the parameters related to the road width.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The explanation text below is in accordance with the right lane driving setup.
Major road
Lane width outer (O) - Defines the outer lane width.
Increased widening outer (o) - The parameter refers to the mechanical widening in curves.
The widening can be calculated using the button Calculate. Depending upon the design vehicle, number of lanes and curve radius this function calculates the curve widening.
The same value will be mapped to the field Increased widening outer.
Alternatively, designers can type in a value for widening.
Lane width inner (I) - Defines the inner lane width.
Increased widening inner (i) - Same as Increased widening outer.
Minor Road
Lane width - Right (Br) - Define the lane width.
Lane width - Left (Bl) - Define the lane width.
Lane width - Deflection Island right side (Brd) - Define the lane width.
Lane width - Deflection Island left side (Bld) - Define the lane width.
Radius minor road - Deflection Island right side (Brr) - Define the radius.
Radius minor road - Deflection Island left side (Brl) - Define the radius.
Standard values
Press this button to reset all parameters to the default values.
Figure 1: Example lane parameters
Edge lines
Use this button to define the shoulder widths of all the joining roads at the intersection.
Shoulder/pedestrian path width and offset of curb from road edge can be defined for all the lanes.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with default driving lane setup, right lane driving for international installation of Novapoint.
Different shoulder widths for different traffic lanes can be defined.
From the major to minor road
Inner shoulder (is) - Defines the offset of the outer shoulder from the road edge.
Outer shoulder major road (os) - Defines the width of the outer shoulder for the road.
From minor to major road
Inner shoulder (is) - Defines the offset of the outer shoulder from the road edge.
Outer shoulder major road (os) - Defines the width of the outer shoulder for the road.
Outer major road
Inner shoulder (is) - Defines the offset of outer shoulder from the road edge of major road.
Outer shoulder major road (os) - Defines the width of the outer shoulder for the major road.
Standard Values
Press this button to reset all parameters to the default value.
Figure 2: Example of edge line parameters
Smooth corners
Use this button to define the edge line radius of the road lines at the intersection.
Defines the type of curves for edge lines from major to minor roads and the radius
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Corner radius
Defines separate settings for the vehicles diverging from major to minor road and the vehicles diverging from minor to major road.
The program handles three different types of curves as an edge line.
Mark the desired type of curve and define the radius.
Simple curve (R) - Curve with one arc element. Define the radius.
Double curve (R1-R2) - Curve with two arc elements. Define the radius for both arcs.
Compound Curve (2R-R-3R) - Curve with three arc elements. Define the radius for the central arc element. Radius for the other arc elements is by default defined as two times and three times that of the central arc element. The user can type in other parameters.
Figure 3: Example of smooth corners parameters
Sketch
Use the button Sketch to select the two centerlines. The parameters can be defined before selecting the road arms or after selecting the road arms.
Command prompts for:
Select a secondary road centerline, Deflection Island's location (bottom point):
Select the minor road joining the main centerline.
Pick centerline primary road, left arm of intersection as seen from the deflection island:
Select the major road to the left side of the intersection as seen from the minor road.
A preview of the intersection will be drawn in CAD.
Whenever values are changed, click the button Sketch to update the preview.
Select Objects
Select intersection elements such as Traffic separator, Right turn lane, Left turn lane, and Islands. Mark the checkbox to activate the object. Click the respective buttons to define the parameters involved.
Road A - Traffic separator and Right turn lane
Notes:
Right lane driving setup:
For Road arm A the user can select Traffic separator and/or Right turn lane.
For Road arm B the user can select Island and Right turn lane.
For Road arm C the user can select Traffic separator or Right turn lane.
Notes:
Left-hand driving setup:
The left turn lane will be available. The left turn lane is an extra lane designed for the vehicles diverging from road arm B to road arm C with a left turn.
For Road arm C - Traffic separator and Left turn separator.
Traffic separator
A traffic separator is a divider designed for road arm A.
All the parameters related to the median can be defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The explanation text below is in accordance with the right lane driving setup.
Parameters
Maximum width (2i) - Defines the width of the median.
Length of widening (Lbu) - Defines the length of the approach for the median.
Turning radius (Rsl) - Define the turn radius.
The parameter is related to the function Island of road arm B.
If the object Island of road arm B is selected, this parameter will be disabled as the program calculates the value for turning radius from the parameters defined for Island.
Front radius (r) - Defines the radius for the front rounded edge of the median.
Displacement from centerline (+/-f) - Define the displacement (across the carriageway) of the median (front part) from the centerline.
Displacement from intersection (dx) - Define the displacement of the whole median away from the intersection of minor and major road centerlines.
Kerb
All the parameters related to the kerb of the traffic separator can be defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with default driving lane setup (right lane driving for international installation of Novapoint).
Parameters
Distance road marking - kerb (kt) - Defines the offset from the road edge and the kerb.
Radius rare circle (rb) - Defines the radius of the rare edge of the curb. The length of the curb will be adjusted within the length of the traffic separator based on this radius.k
Displacement rare circle (fb) - Defines the displacement of the rare edge of the kerb from the centerline.
Taper length (Li) - Defines the length of the taper portion of the kerb.
Radius taper (ri) - Defines the radius for taper.
Radius taper transition (ro) - Defines the radius of transition from taper to straight.
Standard values
Press this button to reset all parameters to default values.
Figure 4: Example of traffic separator and curb parameters
Right turn lane
The right turn lane is an extra lane designed for the vehicles diverging from one road arm to other with a right turn.
All the parameters related to the right turn lane can be defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Right turning lane and/or weaving lane
The right turn lane is the extra lane provided for vehicles diverging from one road arm to the other with a right turn. The right turn lane can be designed in three different types.
Right turn lane only - This type will have an extra lane, only for the current road arm.
Right turn lane and weaving lane - This type will have an extra lane from both road arms.
Weaving lane only - This type will have an extra lane, only for the road arm the right turn leads to.
Depending on the type selected, some of the parameters will be disabled. For the type Right turn lane and Weaving lane, all the parameters will be available. The following text explains the option Right turn lane and Weaving lane.
Distance approach island (a) - Defines the distance from the rear end of the traffic separator of the current road arm to the start of the right turn lane on the current road arm.
Maximum widening (lane width) (i) - Defines the width of the extra lane.
Taper length out (direction of travel (Lu)) - Defines the transition length required for shifting the vehicles to the extra lane.
Length with constant width (Lk) - Defines the length of the extra lane with constant width.
Taper length in (direction of travel (Li)) - Defines the transition length required for shifting the vehicles to the extra lane.
Three Corner Island
In addition to the extra lane, a three-corner road island can also be designed.
Distance road marking kerb (kt) - Defines the distance of the three-corner road island edge from the road edge.
Radius towards the junction (rf) - Defines the radius for the rounded edge provided to the road island at its front portion.
Corner radius (rb) - Defines the radius for the rounded edge provided to the road island at its rear ends.
Standard values
Press this button to reset all parameters to default values.
Figure 5: Example right turn lane
Island
Road Island is a deflection island on road arm B.
All the parameters related to the deflection island can be defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Deflection Island
Width Deflection Island (hb) - Defines the width of the deflection island.
Length Deflection Island (hl) - Defines the length of the deflection island.
Curvature Deflection Island (Rs) - Defines the radius for deflection island.
Increased distance from major road (+/- a) - Defines the set back of the deflection island from the road edge of major road.
Kerb
All parameters related to the kerb of the deflection island can be defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Distance road marking Kerb (kt) - Defines the offset of the road edge from the kerb.
Radius rear circle (rb) - Defines the radius of the rounded edge provided to the deflection island at its rear end.
Displacement rear circle (fb) - Defines the displacement of the rear end of the deflection island away from the centerline.
Radius taper (ri) - Defines the radius of the taper. The parameter reflects if the angle of intersection is other than 90°.
Standard values
Press this button to reset all parameters to default values.
Figure 6: Example island parameters
Left turn separator
The left turn lane is an extra lane designed for the vehicles diverging from one road arm to another with a left turn.
All parameters related to the left turn lane can be defined in this dialog.
A traffic separator can also be designed.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Width median (a) - Defines the width of the traffic separator.
Width left turn lane (b) - Defines the width of the extra lane.
Length of widening (Lbu) - Defines the length of approach for the intersection.
Taper length (Lki) - Defines the transition length required for shifting the vehicles to the extra lane.
Braking distance (Ld) - Defines the stopping distance for the vehicles.
Queue Length (LkØ) - Defines the length of the road required to house the vehicles waiting for a left turn.
Taper radius (Rki) - Defines the radius for the tapered element designed at taper length.
Front radius (r) - Defines the radius of the rounded edge of the traffic separator at its front end.
Displacement from the centerline (+/- f) - Defines the displacement of the front end of the median from the centerline.
Displacement from the intersection (dx) - Defines the displacement of the whole traffic separator away from the intersection in the direction of the primary road.
Kerb
All the parameters related to the kerb of the left turn lane are defined in this dialog.
The unit of linear measurement is meters and angular measurement is decimal degrees.
The interface is in accordance with the default driving lane setup (right lane driving for international installation of Novapoint).
Distance road marking curb (kt) - Defines the offset from the road edge and the curb.
Radius front circle (rf) - Defines the radius of the rounded edge provided at its front end.
Radius rare circle (rb) - Defines the radius of the rounded edge provided at is back end. The length of the kerb will be adjusted with the length of the left turn lane based on this radius.
Displacement rare circle (fb) - Defines the displacement of the back edge of the kerb from the centerline.
Taper length (Li) - Defines the length of the taper portion of the curb.
Radius taper (ri) - Defines the radius for taper.
Radius taper transition (ro) - Defines the radius of transition from taper to straight.
Standard values
Press this button to reset all parameter values.
Figure 7: Example left turn separator
Intersection name
Define a name for the intersection. The name is inserted along the intersection and can be used to identify the junction.
Draw Options
Use this button to configure the drawing setup of different lines of the intersection.
A drawing setup for different lines of the intersection objects can be selected using this dialog.
The different lines of intersection objects are grouped in seven different groups.
The group number assigned for different lines of the intersection objects can be identified from the preview of the dialog.
Project name
The active Novapoint project will be displayed. The dialog Novapoint Project Settings will pop up with this button, where the project settings can be administrated.
Select line setup
The drawing setup for all the groups is selected from the drawing setups listed in the pull-down menus.
Line Setup
Use this button to activate the function Draw Single Alignment (Setup).
OK - Draw
Click OK - Draw to output the intersection to the current CAD drawing.
Example of complete T-Intersection
The example shows a T-Intersection with traffic separator; right turn lane of road arm A, island; right turn lane of road arm B and left turn lane of road arm B.
Figure 8: Example of complete T-Intersection
Next topic: X-Intersection