Adventures in Transit: Rigging a RHW intersection

[jonnyquest 71]

Often while imagining how everything fits together within a region, I have the desire to terminate a RHW at some point within a city. In real life, highways (even interstate ones) occasionally feature intersections with stoplights as they pass through major cities, although this doesn't seem to be something that's natively possible with RHW currently. So after a bit of messing around I was able to come up with the solution in the attached image.

To create my faux intersection, I crossed an avenue with two five-lane one-way roads from the Network Widening Mod (the closest approximation I could come up with for the RHW 10-S I'm working with). Through a careful process of disconnecting tiles and using filler pieces to adjoin my RHW, I was able to arrive at a pretty good visual solution. The autonoma do turn onto the RHW, although they fade away almost immediately after. Go figure 

But more importantly, a look at the Traffic data view shows that the Sims *are* turning onto the RHW here for their commute to the neighboring city. Success!

Has anyone else faced this dilemma of wanting to build a highway intersection like this, and what strategies do you use for terminating highways?

[rsc204 21,866]

2 hours ago, jonnyquest said:

Has anyone else faced this dilemma of wanting to build a highway intersection like this, and what strategies do you use for terminating highways?

So your basic problem here is that a highway with 5 lanes in each direction, can't end at a 2-way road like this. From 1 lane in each direction, traffic has 5 lanes to enter the highway, which is simply inefficient. But in the opposite direction, 5 lanes of highway speed traffic come to a dead halt with only 2 lanes (in each direction again) to exit the 5-lane highway from. Put simply, this would be a traffic nightmare in the real world.

If you want to end a highway like this, start by considering how the lanes would consolidate, ideally at the end you'll end up with no more than 6 lanes (3 in either direction at a T intersection.

By ending the RHW as a RHW-6C here, I've been able to interact with a Ave6 T QuickTurn intersection, which gives turn lanes and the most efficient junction for such a situation.

Yes perhaps some of the NWM OWR-4/OWR-5 stuff would be faster if they are supported, I suspect you'll need + junctions for the lane counts to work.

On the left side of the first image is where the RHW-10S heads off, by using junctions with D type ramps on one side, I've reduced the lane count with the two junctions leading up to the highway terminating. I've also used a RHW C to S transition pieces between the two junctions:

You can't simply think about the number of lanes as more = better. Traffic levels and road usage dictate what is needed and if you don't design systems that take advantage of the capacity, they are just expensive eye-candy.

I'd also advise you to look carefully at how I've designed the major arteries around the highway intersections, Ave and Ave6 have been many used, to create a large capacity where the traffic flows in. Systems like this using further FTL pieces are key to ensuring your networks around the RHW can service it properly. Again I'm just showing an example, but if an AVE-2 is sufficient for ending the RHW, you won't be needing RHW 10s there in the first place.

[Tarkus 6,933]

One of the concepts that comes up in the NAM Documentation (particularly for the NWM) is that of "lane math", to which @rsc204 alluded.  The "Network Capabilities" section in the NWM Feature Guide is particularly useful in this regard.  The two ways lane math works involve the "T-End Min" and the "T-In Max".  The former describes the network that is ending (i.e. the RHW-10S/OWR-5), while the latter applies to the thru network (the Avenue).  Here's the official explanation of them:

T-End Min: If the given network is to end at a T-intersection, this value is the minimum number of total lanes that needs to be on the cross network. For instance, while an RD-6 (T-End Min = 3) can end at an ARD-3 (3 total thru lanes), it cannot end at a Road (2 total thru lanes). Center lanes on TLA networks do not count toward the overall figure (i.e. the TLA-5 would be considered to have 4 lanes total in this instance).

T-In Max: If a cross network ends at the given network in a T-intersection, this value is the maximum number of lanes on the cross network heading inbound to the T-intersection (half the network, in the case of a two-way network, the full network if one-way). For instance, an AVE-2 can have an Avenue or RD-4 end at it (AVE-2 T-In Max = 2, while the Avenue and RD-4 have 4 lanes total, 2 heading inbound to the intersection), but an OWR-1 cannot (T-In Max = 1). Center lanes on TLA networks do not count toward the overall figure (i.e. the TLA-5 would be considered to have 4 lanes total in this instance).

Here's a full listing of the T-End Min and T-In Max values for the NWM and Maxis networks:

*depends on side of ARD-3 used

In short, in order to end an OWR-5 at a T-intersection, you'd need to have a network with a T-In Max of at least 5.  The only possible networks are the OWR-5 itself, the RD-6, the AVE-6, and the TLA-7.  (Again, the TLA-5's center turn lane doesn't count--it's a 4-lane network for the purposes of T-In Max.)  Otherwise, with an OWR-5 (5 lanes per direction) ending at an Avenue (4 total lanes), one of the lanes off the OWR-5 has nowhere to go--it's basically like musical chairs, but with traffic lanes. 

I very frequently pass through the intersection below, between an AVE-6 and a TLA-3 (with a bunch of fancy turn lanes), and turn left off the AVE-6 to the TLA-3.  Once, I had a semi truck (lorry for the UK/Commonwealth types) think the leftmost thru lane was a second left turn lane off the AVE-6, and because of the truck driver's lack of comprehension of lane math (there's a reason there's only one left turn lane there), we were both fighting to get into the one lane heading outbound from the intersection on the TLA-3 (I was in the green path, the truck was in the red path).  I had to gun it to beat the truck and avoid what would have been a nasty wreck.  The fact that it was a vehicle with slow acceleration that was making the illegal turn helped . . . if it had been a normal car, things might not have been so easily avoided.

 

For those of you out there who have wondered why you can't end your RD-6 (3 lanes per direction) at a plain Road (2 lanes total) . . . that is why.  You'd be putting your sim citizens in that sort of a situation every time the light turned green on that RD-6.

All that being, I think the solutions rsc204 proposed are going to be more realistic and elegant than trying to end side-by-side OWR-5s/RHW-10Ses at a T-intersection, even with a network that supports having a 5-lane-per-direction network end at it--and especially with the OWR-5 at its current stage of development.  If you were planning on continuing the OWR-5s beyond that intersection, and it was anticipated to carry a lot of traffic through your downtown area, it'd maybe be a bit of a different story.

-Tarkus

[jonnyquest 71]

On 10/3/2021 at 5:56 PM, rsc204 said:

You can't simply think about the number of lanes as more = better. Traffic levels and road usage dictate what is needed and if you don't design systems that take advantage of the capacity, they are just expensive eye-candy.

I'd also advise you to look carefully at how I've designed the major arteries around the highway intersections, Ave and Ave6 have been many used, to create a large capacity where the traffic flows in. Systems like this using further FTL pieces are key to ensuring your networks around the RHW can service it properly. Again I'm just showing an example, but if an AVE-2 is sufficient for ending the RHW, you won't be needing RHW 10s there in the first place.

I'm aware of the capacity of the 10-S thx.  My goal in the region is to create a large central tile with many commercial office skyscrapers and funnel as many residents into that tile as possible, thus the selection of highway was intended to facilitate that and not merely to serve as eye candy (well, perhaps there was a slight element of that in my selection of 10-S over 8).

Realism isn't really something I go for in my play style and the AVE-2 actually services things okay given the level of I traffic I have currently (I'll have to revisit it as traffic grows obviously). This post was really intended more as a proof of concept for a functionality I'd discovered which I hadn't seen demonstrated anywhere. But it hadn't occurred to me to interface an avenue by dragging it directly into a RHW so I appreciate that tip