Movement |W |C |B |T |S |

Learn how to optimize traffic flow in SimCity 4 with this guide. Discover the best uses for one-way roads, avenues, and highways to keep your Sims moving and your city thriving.

Hey there! So, you're diving into SimCity 4 and want to get a handle on how your Sims get around? It's a big part of making your city happy and functional, and honestly, it can get pretty wild with traffic if you're not careful. This guide is all about mastering movement, from the basic roads to the fancy new stuff in the Rush Hour expansion.

First off, if you haven't already, do yourself a favor and grab the Network Addon Mod (NAM) from Simtropolis. It seriously makes your Sims smarter about choosing their travel routes – they'll actually use public transport if it's faster! Also, check out thy451's guide if you haven't; it's a great primer on the game's concepts.

One Way Roads

These are exactly what they sound like: roads where traffic only flows in one direction. The big upside? Since traffic only goes one way, the road's capacity is effectively doubled. This makes intersections a breeze because you don't have to worry about cars turning across oncoming traffic. The trick, though, is that for every one-way road you place, you'll likely need another one nearby going the opposite direction to manage traffic flow effectively. Think of it like this:

|->->->->->->->->->|
|CCCCCCCCCCCCCCCCCC|
|CCCCCCCCCCCCCCCCCC|
|CCCCCCCCCCCCCCCCCC|
|CCCCCCCCCCCCCCCCCC|
|CCCCCCCCCCCCCCCCCC|
|CCCCCCCCCCCCCCCCCC|
|<-<-<-<-<-<-<-<-<-|

The arrows show the direction of traffic. You can see how having opposing one-way roads nearby is key.

Now, where should you zone these areas? Commercial zones are usually the best bet. More traffic means more potential customers, which is great for businesses. Residential zones, however, can suffer. The constant flow of cars means more noise and pollution, which your Sims might not appreciate. I tend to use one-way roads sparingly, preferring a robust public transportation system. But if you're a big fan of cars or need to manage traffic in the absolute heart of your city, these are essential for keeping things moving and preventing gridlock.

Avenues

Avenues are a game-changer, especially with the Rush Hour expansion. While you *could* just build two roads side-by-side, avenues offer significant advantages. Traffic flows in two lanes in each direction, unlike single-lane roads. This means higher speed limits and much better capacity for handling heavy traffic loads. Roads just can't keep up when things get congested, but avenues can handle it so much better.

You'll want to use these in your busiest areas. Sometimes, you might even need to demolish existing buildings to make space for them. When planning new high-density residential zones, definitely consider replacing smaller streets with avenues. High-density living inevitably leads to more cars, even with good public transport.

Don't go overboard with avenues, though. They have a higher maintenance cost. However, the boost in Sim happiness and improved commute times often pay for themselves through increased tax revenue. Here’s a layout idea I use for planning residential areas:

===============================
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
+++++++++++++++++++++++++++++++
+++++++++++++++++++++++++++++++
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
=RRRRRRRRR=RRRRRRRRR=RRRRRRRRR=
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
=CCCCCCCCC=CCCCCCCCC=CCCCCCCCC=
===============================
Key
= means Road
+ means Avenue
C means Commercial Zoning
R means Residential Zoning

This basic plan shows residential lots facing the avenue. This way, traffic from residential zones flows directly onto the avenue, relieving congestion on the smaller roads. The commercial zones nearby provide local jobs, further reducing the need for Sims to travel long distances and easing pressure on the avenue. Remember, this is just a starting point! You'll still need to add public transport and other amenities to make it a great place to live.

Speaking of public transport, there's a fantastic mod available on Simtropolis that lets you place bus or subway stations right on roads, avenues, and streets. It saves space and allows for integrated transit systems with minimal maintenance. With this mod, I've seen maintenance costs for stations and subways around §3,000, while generating about §8,000 in fares. See? Public transport can be profitable!

Ground Level Highways

Okay, I'll be honest, I'm not the biggest fan of highways in general, and ground-level ones are no exception. Their main draw is their massive commercial development boost. Ground-level highways are cheaper to build and maintain than their elevated counterparts. However, unlike elevated highways, you can't build roads or streets underneath them. This means you'll need overpasses to let traffic cross, which can get expensive to maintain if you have a lot of them.

These overpasses are also crucial for highway access and act as U-turn points. Traffic can enter via side on-ramps, which run parallel to the highway, and then use the overpass to reverse direction. Like other highways, they have three lanes.

My main issue with highways lies in their intersections. Roads and avenues allow for natural turning points, but highways require specific, space-consuming junctions like T-junctions and the infamous Cloverleaf. The Cloverleaf is the worst offender, gobbling up huge amounts of valuable land that could be used for your city's economy. T-junctions, while slightly better, still consume a lot of space where one highway meets another perpendicularly.

Another problem is lane management. While there are three lanes, there's no easy way to switch between them or directions without dedicated interchanges. The need for overpasses to facilitate U-turns and crossings is a constant design challenge.