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RHW Interchange Guide - Moved To A New Home! (See the Child Board Above)

Started by Haljackey, January 23, 2009, 10:33:13 AM

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Have you found this guide useful?

Yes- very useful
256 (82.3%)
Yes- somewhat useful
44 (14.1%)
No- too simplistic
4 (1.3%)
No- too confusing
7 (2.3%)

Total Members Voted: 311

Jill Jacobs


Ok, time for another one, I told ya I'd be quick!   ;)

Section 2.5: Parclo A-4 Interchange with single acceleration/deceleration ramps.

This guide will be similar to 2.4 (the last one), with a twist.  Instead of having two ramps feeding traffic to the highway, there will just be one.  You might think to yourself this may save some space, when it is actually more space consuming than the dual-ramp setting.  The advantage of this setup is to make entering traffic more organized and contained, as well as allowing for proper merge lengths, essential for creating these realistic interchanges.

Like the last guide, I will make the accel/decel lanes 7 tiles long in this guide (per lane).

This time round its best to make yourself a RHW beforehand so everything can fit perfectly in place.

Since this is an elementary step, I'll show how to make it once more, taken from the first guide.

Place your starter pieces...

Drag the RHW using the RHW tool...

(Optional) Delete the starter pieces to create a RHW without any overrides.

And drag the stable network over it.

Now that you have a RHW, its time to build the interchange.  Start like so.  Construct part of your overpass as well as the MIS splitters as displayed, at least 3 tiles away from the overpass.
-Make sure you select the RHW-4 splitter and not the RHW-2 splitter.  You'll have 2-way traffic if you do that which is not what we want here.

Start by making your ramps first.  The example shown is the most compact you can build.

With your ramps in place, its time to finish building the overpass.

Now start getting your off-ramps ready.  Drag a RHW-2 from the avenue until you reach the RHW as shown.

Plop a type "C" ramp on the RHW at the edge of the RHW-2.
-You'll see a flawed RHW-6S as a result of plopping the type "C" ramp.  This is known.

Drag the stub from the ramp on your RHW-2 to establish an override.
-Also, redraw the highway from the offramp toward the overpass to restore it to a RHW-4.

Once you reach this point, you might want to consider what you want to do with your off-ramp.  Do you want it to be higher capacity?  If so you can convert the MIS to a one-way road for the intersection.

Or even better, you can widen the ramp all-together.  In this image I replaced the type "C" ramp with a RHW-6S/dual RHW-4 transition and dragged the RHW up to the edge of the intersection, joining it with a one-way road.

Getting back to making the interchange, its time to join our on-ramp to the main highway.  There are actually two ways you can do this, and I will show both.

The first way you can do it is to plop a RHW-8/dual RHW-4 puzzle picece, making both onramp lanes reach the highway.

Here's a shot of the setup away from the centre of the interchange.

Then just evenly apply your RHW-8/6S and RHW-6S/RHW-4 transition along the roadway.  This example is shown with a 7 tile transition per lane.
-Do the same with your off-ramp, which just requires the RHW-6S/RHW-4 transition.  It's best to make it 7 tiles long as well to make it match the length of your other transitions.

The second way you can do this is to allow the joining lanes transition to one before it reaches the highway.  This is a more realistic transition.

Drag your RHW-4 from the MIS splitter for 7 tiles, then apply the RHW-4/MIS transition.  Join the ramp to the highway using the RHW-6S/dual RHW-4 transition and drag for another 7 tiles.
-Don't forget to apply the RHW-6S/RHW-4 transition for your off-ramp!  It's best to make it 7 tiles long as well to make it match the length of your other transitions.

...And you're done!  In this zoom out you will see the first on-ramp configuration used in the north and the second configuration in the south for comparison.

Here's a few modifications to the interchange you can make.

In this image, I moved the outermost on-ramp connections to the avenue to the other side of the intersections.  This will improve traffic flow and reduce congestion.

Here, I've extended the loop ramps by one tile, making them look more realistic.

Lastly, I used one-way roads to connect the outermost on-ramps to the avenue, which resembles an off-ramp.
-You could also convert this part of the avenue to a RHW-4 and use a type "A" ramp to connect the MIS.

Anyways, that will do it.  I hope you found this guide useful!


Great article hal! This will indeed be useful.. especially to me.  ;D Thanks!


Copperminds and Cuddleswarms


I really want to see you making a Basketweave (for interchanging a Multi-RHW)
You already inspirit me with the last one :thumbsup:


A great guide! &apls
I've learned it!


2010.8.4 - I get on SC4D with PSP. So cool.:D
2010.8.14 - I can get on the Internet at home.:)

KoV Liberty

I have no Ideahow to make a Turbine inerchange. Plus I think we all could use a break from offramps.

My new MD. Check it out if you wish.

Adrian, I miss you man.


These are fabulous interchanges!  I'm still a newbie at building transport networks.  I've finally decided to use RHW as my main city connectors instead of Avenues.  I have a problem here.   ()what()  I don't want to post all over the place but I posted on NAM problems once already.  Figured out to tab through the RHW starter piece to get to the MIS ramp and MIS elevated ramp pieces.  Still have a problem... how do I get things to slope up or down?  Here's a picture of my further attempts at this simple interchange.    &ops   :(

EDIT:  I found the on/off ramp for the MIS thanks to  carkid1998    .

One more question:  "And drag the stable network over it."  Does this mean using the basic RHW tool and dragging over just like I would with a RR station (rail tool) or Marrast's underpass pieces (rail & road tools)?


First, bulldoze the MIS starter pieces. Then plop the ground-to-elevated MIS transition (near the end of the transitions tabring) in their place. That's all you need to do.
NAM Team Member | 3RR Collaborater | Virgin Shores


Good guide-I would have never known how to make the diamonds and I didn't know what a parclo was.
I am not a leader ;)


Greenbelt -

You should not need the MIS or EMIS starter pieces at all - the on/off ramps will act as starters.

And as deathtopumpkins posted, you need the ground-elevated (or elevated-ground) MIS transition from the transitions tabring. It will say ON or OFF in various positions - OFF is for traffic going down and ON for traffic going up.

KoV Liberty

What he said. Also for MIS ramps the easier thing to remember is that the Yellow Line is always on the left.


My new MD. Check it out if you wish.

Adrian, I miss you man.


I am most interested in how to make the trumpet(the T interchange) because we only got + interchanges tutorials on this thread, I would like to know how to make a nice looking T interchange and Y interchange

Those are good understandable tutorials  :thumbsup:

KoV Liberty

Hey I did a trumpet interchange for my MD so I thought I would help you out. I don't have multiple pics just one, sorry! Here it is...

My new MD. Check it out if you wish.

Adrian, I miss you man.


Come check out my new exciting MD:

"The Life of a Tour Guide"



Its a nice basic start driftmaster. But don't you think it could've looked better if it did have curved turns like haljackey's RHW has? But really, you got the basics down better than I would since I have trouble making realistic RHWs.


Haljackey, great tut, but the style you used, is better off in reverse where the traffic has ramps to exit each side on to the avenue, instead of having to wait at a light, because building the on and off system in reverse, the traffic does not have to be fighting to merge onto the MIS ramp just by making a left across the avenue to go onto the highway.


Quote from: j-dub on October 01, 2009, 08:07:20 PM
Haljackey, great tut, but the style you used, is better off in reverse where the traffic has ramps to exit each side on to the avenue, instead of having to wait at a light, because building the on and off system in reverse, the traffic does not have to be fighting to merge onto the MIS ramp just by making a left across the avenue to go onto the highway.

You would think the reverse would be better off, but in reality its not.  There's a simple explanation for that, in fact.  The arterial road (road/avenue) has a lower capacity than the highway (RHW).  Because of this, the extra ramps connect to the arterial road to make it more efficient, thus reducing traffic congestion.  Although all traffic exiting the highway must use the stoplight, this means it can be controlled at one point, making it more efficient.  In addition, these intersections are located away from the overpass allowing for more traffic movement.  (If a right turn ramp is made, then the lights just handle left turning traffic.)
-This design has won many awards and has been used commonly since the 1970s.  Its also an excellent alternative to a cloverleaf interchange when used with an arterial road.

Anyways, I do have something new to share.  Although this is technically "my" RHW interchange guide, that doesn't mean other people can't show their guides/creations here.  (I just have to approve them first! &scl()).  A Youtube user, who goes by the name of Asteconn, has created several RHW video tutorials on Youtube (you guessed it! :P).

If you want to take a look at his tutorials, here's a link to a playlist containing what he has made so far:

And a playlist video embed:

Oh, and by the way, he's British, so he drives on the left.  Right hand drivers, keep this in mind as he builds his junctions.  ;)

I hope you enjoy them!


The very least, that award winning design, would have signals on all sides coming to an avenue. In SC4, by default, it does not. This type of opportunity, I take advantage of and make custom signals, and signage for.

In the picture, it is too close to do this next thing, but just for future reference,
rather then first connecting the OWR from the avenue to the MIS, you can just connect the MIS directly to the avenue on an angle, instead of having traffic fight to merge before the ramp. Yes, I have been on this in reality, the old dual lanage on the ramp, merging on the ramp before merging onto the highway, and I still think it is stupid, and unsafe even then, especially with the slow semi trucks, because on a ramp, you need to speed up to merge, or you get hit, those guys slow you down, but that is besides the point. In situations other then this, MIS can make direct angular avenue connections, still without crossing the median, provided it hits both avenue tiles.

In reality, I don't know who made this idea, but I really came off an exit ramp where only the one side of the avenue going to the right had a stoplight and the other side on the left where it T's did not, and that made it harder, you had the green, but the side going to the left after did not even have a signal at all, and crossing was harder, because they saw the arrangement in SC4, and used it as a bad example.


Thank you so much Halijackey!  This is exactly what I was looking for!  This is one of the main reasons I did not like the RHW at first...the interchanges are very complicated.  But this makes it a lot easier.  Thanks again for all your hard work, and keep it up!