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Trumpet Interchanges

Started by Haljackey, November 26, 2011, 01:05:26 PM

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Section 3: Trumpet Interchanges

This part of the guide will cover trumpet interchanges, a popular, realistic way to connect two RHWs together in a 3-way intersection.  Although they consume a good amount of space, trumpet interchanges are cheap to build and their design works particularly well with toll roads.

In right hand drive, the one loop in the trumpet interchange usually contains the ending highway, but this design can be mirrored to contain the starting highway.

3.1 Simple Trumpet Interchange
3.2 Complex Trumpet Interchange
3.3 Compact, Complex Trumpet Interchange
3.4 Video of a Realistic Trumpet Interchange

Back to the Table of Contents


Section 3.1: Simple Trumpet Interchange (Created by Haljackey)

This post will show you how to build a simple trumpet interchange, perfect for those who are new to the RHW or when space is a constraint.

So let's get started.  Construct your primary RHW (the one that is not starting/ending at the interchange).
-I am using the RHW-4 with a one tile median for this example.

Now construct a pair of MIS overpasses like so:
-Make sure the yellow and white lines line up to ensure you have a working connection.

Allright, on one end of the MIS overpasses, plop two MIS/RHW-4 splitter pieces, one for each direction.

Now, begin to drag your MIS stubs to create a design like so:

Select RHW-4 ramp type "B", and plop four of them where the MIS meets the RHW-4.  It should look like this when finished:

Lastly, extend your newly formed RHW network.

...And there you have it.  A trumpet interchange!

That also marks the first RHW-to-RHW interchange in this guide.


Section 3.2: Complex Trumpet Interchange (Created by Haljackey)

Fasten your seatbelts and prepare yourself, for I am about to show you how to make a large, realistic trumpet interchange.
-Note: you will need the hole digging lots for this guide.

I am going to be as comprehensive as possible, but I don't want to flood the page with an exceptional amount of images.  Despite this, this will be the largest tutorial in the guide so far.  Just make sure you have enough experience using the RHW before following along.  If this is too much for you, then I recommend using the simple trumpet interchange guide in the post above.

This interchange will have a higher capacity than the simple trumpet interchange because I am going to use RHW-4 for the ramps instead of the MIS ramps.  The advantage here is that by using RHW-4, smooth curves can be made.  Proper acceleration and deceleration ramps will also be constructed.

Let's begin.  Like the last guide, I am using a RHW-4 with a one tile median.
-Place your ground lifters from the hole digging lots at least one tile away from the highway.

Now drag road.  Start at the ground lifter, and drag away from the RHW.

Demolish the roads and the ground lifters. 
-Now is also a good time to adjust the slope of the newly created hill.  I recommend using a slope mod to achieve this.

Use road, street, or RHW stubs to create a 3x3 box at the top of your hills.
-At this point, I have also further sloped the sides of the hill to create a more realistic appearance.

Delete the two rows of stubs closet to the RHW and drag a road or street along the side of the RHW for two tiles.  This will also flatten the area so a smooth overpass can be made.

Construct two RHW-4 overpasses using the Elevated RHW on-slope pieces.
-Make sure the yellow and white lines line up to ensure you have a working connection.

Begin to drag your RHW from the overpasses.  Be sure to leave enough space for smooth curves, which will be added later.
-A good trick to ensure you left enough space is to plop it first, then demolish it.

Begin to drag your RHW from the overpasses in the other direction.  Place a pair of smooth inner RHW-4 curves where the slope ends.
-In this photo, I have turned on the grid to make it easier to see where the slope ends.  I use a very restrictive slope mod to create a low incline/decline angle.

Now to construct the ramps.  Use a pair RHW-6S to dual RHW-4 pieces at the edge of the inner curves.  Then drag the RHW-6S for a few tiles before using a RHW-6S to RHW-4 transition to start/end the lane.  I have used the RHW-6S for 7 tiles here.  Also now is a good time to drag your new RHWs from the curves and connect them to the main RHW in a similar fashion.
-You can also use the dual RHW-4 to RHW-8 pieces here if you want, depending on how high capacity you want your starting/ending highway to be.

Place a RHW-6S to RHW-4 transition at the edge of the overpass like so:
-As of RHW 3.2, the El-RHW-4 cannot cross networks wider than the RHW-4.  The extra length of the overpasses allow for a wider RHW to pass below when this is added in a future version.

Allow about 7 tiles of RHW-6S before placing the RHW-6S to dual RHW-4 piece.  This will give a realistic look to the deceleration lane.  (Road stubs are used here only to show the 7 tiles)
-Again, the length of the lane can be whatever you wish, I just think 7 tiles is a good length to use for the purpose of this guide.  (Personally, I like to use 9 or more tiles.)

Start to drag out your RHW from the on-ramp.  This will form the loop of the trumpet.
-Also, if you have not done so yet, connect the outer ramps to the main RHW as seen in the top-right of this image.

Construct the loop, joining the overpass with the on-ramp.  Leave enough room for curves. 
-Also construct the outer ramp that follows the trumpet.

Add in your smooth curves.  Outer curves go on the outer RHW, inner curves go on the inner RHW.  Makes sense, right?  :P

Join your outer ramp with the main RHW.  Its pattern is exactly like the other ramps.  Allow 7 tiles or so for the off-ramp.  Place the last smooth curve here.

Now is a good time to smoothen the terrain if you so wish.  I would avoid using the level terrain tool as it can demolish all your hard work.  Drag a road/rail network to create a smoothed slope and then demolish it. 
-Again, this is why a slope mod comes in handy.

The finished result.  The bumps and steep slopes in the hills are now smoothed.

...You're done!  This is a large interchange, so I'll have to zoom out to show the whole thing:

Congratulations!  You have now made a realistic trumpet interchange!  &apls &apls &apls

Additional Image:
Like almost every interchange, it can be further customized.  This image shows the loop ramp elongated to create a more circular curve.  However, this will increase the size of the interchange by a significant amount and is not at all needed.  Some players might find this appearance to look better than a straighter loop shown in this guide.

Anyways, I you enjoyed this guide!  Have fun constructing a complex, realistic trumpet interchange!


Section 3.3: Compact, Complex Trumpet Interchange (Created by Haljackey)

This guide will show you how to make the trumpet interchange I displayed in Section 3.2 more compact, while still maintaining its complexity and realistic look.  The major change here is that the loop ramp will be considerably more circular, reducing the footprint of the interchange.

I will also show some other applications to the interchange at the end of this guide.

To start, follow Section 3.2 until you see this picture.

Now, unlike the last guide, I am going to construct the loop's on-ramp (a dual RHW-4 to RHW-6S transition) on the other side of the overpass.
-Don't worry about the graphical problems, just redraw the network to fix them.

On the other side of the overpass, begin to drag out your RHW in the form of a trumpet.  For the loop ramp, let the RHW-4 follow the mainline for about 7 tiles before curving it (this is where the RHW-6S to RHW-4 transition was in section 3.2.).  This will allow enough room to construct the loop ramp.
-As stated in the last guide, the widest RHW network the El-RHW can pass over is the RHW-4.  By drawing two RHW-4s side by side, a "loophole" can be found as you can connect them together on the other side to create a wider network (such as a RHW-6S or RHW-8.)

Now plop in your smooth curves.  Remember inner curves go on the "inner" RHW, and outer curves go on the "outer" RHW.
-Watch your slopes as well.  The smooth curves are larger than the standard curves, so they require more room to create a smooth slope.

Again, don't forget about your outer RHW's off-ramp.  Use a a dual RHW-4 to RHW-6S transition once again and a (inner) smooth curve to hook it up.  Extend the RHW-6S for about 7 tiles before using a RHW-6S to RHW-4 transition.

And there you have it, a compact, yet realistic trumpet interchange!
-Don't forget to connect the loop ramp to the main RHW.  See the step above for instructions.

The size of the interchange is considerably smaller than the trumpet shown in the last guide.

Other applications

These pictures will demonstrate some additional things you can do with this trumpet interchange and is not part of the guide above.  Again, this is optional.

Since we now have some extra room between the loop ramp and where the on-ramp is, this is a good spot to plop a RHW-4 to MIS transition.  This will concentrate all entering traffic from the loop into a single lane, making transitions smoother when the MIS meets the on-ramp.  Change the RHW-6S to RHW-4 ramp to a RHW-4 type "C" ramp. 

The rest of the route can remain the same as shown in the guide.


You can also use dual RHW-4 to RHW-8 transitions in place of the dual RHW-4 to RHW-6S transitions.  This will create a wider RHW network able to handle higher traffic volumes.

The rest of the route can remain the same as shown in the guide.

Here's what the high-capacity interchange looks like when zoomed out:
-Note how I didn't use any transitions to narrow the RHW-8 to a RHW-4.

Bonus images

So after I made the interchange displayed in the last image, I decided to play around with it and add in some eyecandy.  Here's an example of what the interchange can look like when it is all "decked out":

Zoomed in:

Zoomed out:

Anyways that will be all for now.  Have fun constructing your own compact, realistic trumpet interchanges!

I have also added a poll to get some feedback on this guide.  Please vote even if you haven't found it useful!

If you have any questions or comments, please feel free to post them below.


Section 3.4: Video of a Realistic Trumpet Interchange. (Created by Samerton)

In this tutorial I will show you how to create a trumpet interchange.

Don't forget to watch in 1080p ;)

Thanks Haljackey for letting me post this here.