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Cities: Skylines Efficient City Guide - A grid city that is better than grid cities.

Cities: Skylines Efficient City Guide

Building a modular city that is simple, convenient, and scalable.

The goal of a city builder is not to simply build a place for people to live and work, but to build a traffic network that avoids jams, and provide public services that efficiently satisfies the most people. However, the larger the city, the more complex it becomes to expand without creating problems. What works on a small scale may not work on a large scale, so you need to create a system that allows you to easily expand in an orderly manner to avoid painting yourself into a corner.

Cities: Skylines is complete enough without DLCs or mods, so this guide is for the unmodded base game.

Modular road hierarchy

The biggest rookie mistake is using an ordinary grid of roads. Not only is it boring, it leads to worse traffic flow because it creates intersections everywhere, making it hard for traffic to quickly pass through without running into each other. A good road layout is one where you have small, dead-end neighbourhoods that connect to higher capacity central arteries that connect to long-distance, limited-stop expressways. This ensures that vehicles do not go where they do not need to and interfere with local traffic.

If you have seen my SimCity 4 guide, I like to build my city in modules because they are simple to build, space efficient, rail and highway friendly, and self-contained with services. It breaks down a big problem into a small problem repeated over and over. But rather than replicate my SimCity modules in this game, I have come up with a new module design tailored for Cities' mechanics. There are no hard map edges and you start in the middle of the region, so you cannot plan the whole city from the start; you are expected to build your city organically. This means no dead-end modules intended to be built along map edges, and consistent module spacing to run highways and rails through any path. Any excess spacing can be filled in later when you have settled on a layout.

One of the problems with Cities is that it only provides grids and guidelines relative to existing roads while roads can be placed with fluid precision on the ground. While this allows you to build more curvy cities, it complicates straight-line layouts that require everything to line up exactly. However, Cities provides an asset editor that lets you pre-make roads on a fixed grid to use as a template you can paste in game to make city expansion quick and accurate. The editor limits how big you can make a module, but you can create a quarter of a module that can be rotated and snapped four times to form the complete module. You can also create difficult intersections like highway exits so you can be consistent without wasting time making it again every time you need one.

When designing road templates in the editor, one factor to watch out for is inclines. The terrain in the editor is perfectly flat, but real maps are bumpy. If you try to build a pre-made incline on a slope, any bridges and tunnels will tilt with the slope and may result in "Slope too steep" errors. You can avoid this by making your inclines as shallow as possible, although this will take up more land space.

Road considerations

The main advantage of road hierarchy is that it collects cars so that they don't go where they don't need to. The main disadvantage of road hierarchy is that it collects cars so that they get in each other's way. Fixing road congestion is not as simple as just upgrading to a wider road. Intersections are a major point of trouble because cars will block each other as they turn. Often, you will end up with a long line of cars that want to turn in one direction, typically in the direction of the highway, so they jam together on one lane, leaving the other lanes empty. Providing multiple paths to the same place can fix this. You can also use one-way roads to redistribute traffic and improve flow. One-ways are good for intersections because they allow two lanes to turn into them, which reduces line-up. They can also prevent left turns so cars will not block each other.

Four-lane roads can be zoned, but they have a middle partition that prevents traffic from crossing over. This is important to consider when you have a long stretch of road with zones on both sides. Traffic coming from one direction may be forced to drive around to reach buildings on the wrong side of the road. Six-lane roads do not have such a partition and are your only option for both capacity and flexibility.

Highways are ideal for express roads across the city, but intersections take up a lot of space, not to mention you are required to build opposite directions separately. If you want to run highways through your city, I highly recommend having only one direction down one path, and the opposite direction through another path. This distributes the traffic so that cars wanting to enter the highway are not interrupted by those exiting and vice versa. If you want to keep both directions together, you can end the highway into a single intersection by merging the highway into a six-lane road with a Y-connection, but this can lead to congestion due to the bottleneck.

A developed residential module with all services A module is a self-contained community that has everything it needs. Expanding the city is a just a matter of building this over and over again. A quarter of a module built in the asset editor With the asset editor, you can create a perfectly sized and shaped piece to make module construction a breeze. Highway access point that exits on the left and tunnels underground to save space and reduce congestion Highway ramps that enter/exit on the right take up a lot of land space, but this method keeps the highway narrow enough to fit between modules, avoids bottlenecks, and does not interrupt the road above. Those little Y-ramps can be changed to two-lane, one-way roads for double wide access. One-ways used to organize highway access One-ways can be used to prevent left turns, which allow cars to turn without interruption at an intersection.


Another rookie mistake is filling out every space with zoning, leaving little to no green space. Not only is noise pollution a factor, but every building adds traffic, more so with high density (HD). Therefore, to keep traffic flowing smoothly, you have to limit development concentration and spread things out. HD is not a pure upgrade of low density (LD) because the sheer number of people crammed into such a small area will create a traffic nightmare. Your city should be mostly LD with spread out pockets of HD.

You should also avoid putting all of one zone type together in one area to prevent the entire city from converging into one place. Modular city construction allows you to be flexible with zone placement, so you can scatter different zones all around the city to keep things distributed. However, keep industry and commercial next to each other to ensure quick delivery of goods.

An efficient city is one where the supply of residents is equal to the demand for workers so that everyone has a job and every business has enough workers to operate. You can respond to RCI demands as they come, but knowing the correct zoning ratio is useful so you do not make a mess. The zoning ratio I have found to work is roughly 4:1:1 RCI. Once HD zones are unlocked, residential and commercial modules can be more densely developed while industrial zones do not have HD, which allows the residential ratio to drop somewhat. However, it is safer to have too many than too few residences to avoid worker shortages. You also have to give new residents time to become educated or else high-level commercial zones will not have enough educated workers or wealthy customers.

Just keep in mind that you will need a lot of residential modules for each commercial or industrial module regardless of what the demand meters show. The demand meters quickly deplete as zones are built, but this is only temporary to prevent you from building too much at once. Unemployment is a more accurate indicator of overall zoning needs than the demand meters. 3% unemployment is the breaking point before adding more workplaces will result in worker shortages, so be sure to build residences first so people have time to move in.

Zone distribution map showing distributed zoning An efficient city has different zones scattered around, like multiple small cities put together to keep things in balance. Residential module between an industrial and commercial module while insulated from noise The beauty of modular construction is that it lets you build residential zones next to commercial and industrial zones and not have to worry about noise pollution.


Services increase land value in a circle as big as the happy faces appear when you build them, and they are required for buildings to level up and generate more tax income. Bigger and more happy faces indicates a stronger effect, but zones that are farther away receive less of an effect, so having perfect coverage is difficult. Services do not have any marginal cost scaling, so you can build as many as needed to cover as much as possible. Large versions of services (e.g. police headquarters, hospitals) provide higher capacity and coverage range, but they are not required to reach max level, and they are way more expensive than just building multiple small facilities or just leaving stragglers with less than perfect coverage. One peculiarity to note is that elder and child care facilities do not create happy faces when you build them, but they do increase land value.

In a modular city, each module is sized so that it can efficiently have its own services. But even then, zones on the edges tend to have insufficient land value to max out. Adjacent modules provide overlapping service that makes up for it, but buildings on the city edge will suffer this problem.

Public transportation stops also act as services that contribute to building levels, and you can level up stubborn zones by spamming bus stops that don't go anywhere. Office zones are especially dependent on public transit routes to level up, and you really need to cram bus stops on every stretch of road to get them to max level. They won't even see much usage either, yet they make office people happier for some reason. In fact, the same is true for health care. With a well-designed city, people rarely get sick, yet clinics increase land value just by existing. You will end up with tons of empty facilities that generate profit because people somehow become wealthier by the mere presence of them.

Office module with bus stops crammed into every street Offices love bus stops. I have no idea if there is a more elegant way to max out offices.

Mass transit

Buses and subways are not optional, they are vital for cutting down road traffic and generating supplemental income. Mass transit is a bit complicated to set up because you have to manually plot routes that form a closed loop. How you design routes can affect traffic flow as well because you can have multiple overlapping routes getting in each other's way. Like roads, an efficient mass transit system follows a hierarchy, with each type of transit serving its own purpose. Buses are for gathering and distributing people in a small area, while subways and trains are for transporting people across the city.


Buses are the first form of mass transit you get, and it is also the most complicated to set up effectively. For a modular city, the most effective bus route system is a linked array where each module has outbound routes for north, east, south, and west linking only to the adjacent modules. The northbound route connects to the southbound route of the north module, and so on. This allows people to hop from one module to the next and reach any module in the city. However, it is still faster to take subways to travel longer distances. Any redundant links that just go from residential to residential can be excluded to save money.

The biggest problem with bus stops is that they have a tendency to get overcrowded with hundreds of people while a single bus can only hold thirty. While you can increase the number of buses, that will easily cause road congestion. To fix this, you can reduce the number of stops, and create a separate overlapping route that makes up for the lost stops. Rather than having one route make eight stops, you can have two routes with four stops each. Buses will always stop at each of their stops regardless if they are full, which just slows them down. If a bus is filling up at the first stop, there is no point making it stop to pick up even more people along the way. However, do not put stops on top of each other or else the buses will get in each other's way and create traffic jams.

Mass transit network that covers every module A good mass transit system provides full coverage of the entire city to encourage everyone to use it, reducing overall traffic and making you money. Close-up of a single modules bus stops There are two separate routes going north (red and orange). Each route has only two stops on opposite sides in the module, which allows the buses to move people faster than if there was just one route with four stops.

Subways and trains

Subways provide higher capacity transport over buses, but they are more expensive and less flexible. Rather than replace buses, subways are best used to collect bus traffic and tunnel the passengers straight to commercial centres. Buses will then distribute the passengers where they need to go. Subway trains can reverse direction at a stop, so setting up routes is a lot simpler than for buses. Just build a subway line that runs through all of your commercial zones and draw a route through all of the stations in both directions.

Subway stations have two platforms that go in opposite directions. If you have two routes going to a station, make sure their stops are not on top of each other or else they will get in each other's way. This also means that you cannot have an elaborate interconnected subway system with multiple routes going to the same station. A subway system should be a line or a loop, never some horrific magnetic field converging into a single station. If you need to connect multiple routes to one place, build separate stations for them. People will walk from one station to another to transfer.

Cost is another problem. If you keep the global metro budget at 100%, you will have a hard time maintaining net profit because the subway stations themselves incur a hefty fixed cost just for existing. An income exploit you can do is reduce the global budget to minimum and just increase individual line budget to get the needed number of vehicles. This halves the cost of each subway station while still allowing them to service all of the passengers. Only increase the global budget if you need more vehicles than the individual line budget allows. If you want to save even more money, you can use above-ground metro stations instead of subways.

Passenger trains are the highest capacity mass transit and also the most expensive. These have niche use in the event that subways get overburdened with passengers who want to travel to the other side of the city without stopping along the way. You can see this if your subway trains are filling up at the start, but no one wants to get off at each stop along the way. This might happen if you have multiple stops in residential zones before going to commercial zones.

Subway station with two routes going in opposite directions without interference When plotting two different subway routes going to the same station, start at the station and plot in their respective directions to ensure the trains start and return in different lanes so they don't block each other.

Cargo train

Industries need to transport raw materials from outside for production, and then deliver their products to commercial zones or outside to be sold. By default, they will do this via roads, but you can use cargo trains to ease the burden on your road infrastructure. However, cargo trains do not actually reduce the amount of road vehicles because the cargo eventually needs to be delivered by road to reach their destinations. Delivery vehicles also have to drive back to their origin building after dropping off their cargo. What trains do is allow you to change the origin of industrial traffic so they do not get in the way of other traffic, allowing you to better balance the load.

Because trains cannot turn 90 degrees, intersections have to be built as a diamond or triangle with sides at least as long as a cargo train. Trains are quite long regardless of how much cargo they carry, and it can lead to circular gridlock at intersections if the rails are not long enough to prevent the trains' tail ends from sticking out and blocking the others. This means train intersections take up a lot of land space, but in tighter areas, you can s-curve the rails to extend them.

The biggest drawback is that the terminals are expensive and generate no income to offset the cost, although they do provide indirect income by levelling up nearby industry. Therefore, do not build them simply to transport goods to isolated commercial zones, express roads are preferable. You can also lower the train budget to save money, but this will reduce each terminal's service coverage range. Although, you could just spam bus stops to make up for it.

Two cargo terminals distributing traffic Multiple terminals may be needed to distribute the load. One-way roads are key to dividing traffic. Train diamond intersection Green space is important to fit intersections like this. Small rail triangle intersection with circular gridlock Everyone waiting for each other to get out of the way, so they end up like crabs in a bucket. Same rail triangle intersection, but with curved sides to lengthen them If the shortest path between two points is a straight line, curve it until they fit!

Taxes and Policies

Taxes not only affect your income, but happiness and demand. Commercial zone happiness is particularly sensitive to taxes, and it will remain stubbornly low unless you lower taxes for them. But if you need money, the maximum taxes you can set in all zones before people will threaten abandonment is 12%. This will not affect demand enough to make it impossible to grow, so you can keep it at that to maximize income. In the late game, lowering taxes even by 1% will really hurt your income, so if you want a low-tax regime, you will need to sacrifice nice things like unique buildings to stay afloat. If your priority is rapid expansion, you can temporarily lower taxes to get a demand spike to help you build up faster. If you really need cash, you can temporarily raise taxes above 12% and then lower it before people abandon.

Policies are options you can enable to control behaviour and improve the effectiveness of various things in the city at a cost. You can also set districts and apply policies only to those districts if applying them city-wide will cause problems. Some policies are more useful than others, and some are just pointless for role-playing. The best policies I have found are Parks and Recreation, Small Business Enthusiast, and Big Business Benefactor. The income boost from those business policies is huge with developed commercial zones, so enable those as soon as you can.

Industrial Space Planning and Industry 4.0 seem great on the surface, but they increase industrial traffic substantially without much income boost. Industry 4.0 is especially difficult to work with because your entire city needs to be in a fully educated steady state or else industries will complain about a lack of educated workers, even if you apply it to only one single district. These are best used on isolated specialized industries to maximize their output and reduce city reliance on importing their resources.

High Tech Housing seems effective at levelling up residential zones at first, but it is actually more expensive than building enough services to maintain max level. You can temporarily use High Tech Housing to max out your residents, use the income to build every service, then disable the policy. You might end up with a few stragglers, but they are worth sacrificing. They will eventually be replaced with a slightly lower income household anyways. Some inequality is just a fact of life, but at least no one is poor.

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