So I noticed that I can basically connect any type of road to a highway, and this got me thinking. What advantages does using a highway ramp actually bring?

Is it just that traffic can leave the highway at higher speed? If so why not just use a highway to connect right to your road? Does the one-way nature of a highway ramp make it more efficient?

Plus it seems that highway ramps are single lane, which would make them less efficient for higher density traffic.

2 Answers 2


If you use any multi-lane one-way road as an exit to a highway, you effectively reduces the highway to two lanes at that point. This is because the lane on that side of the highway typically becomes turn-only, while the middle lane will become turn/straight. Unsurprisingly, this can be bad for traffic flow on the highway. Note that this also applies for splitting a highway into two highways.

You will find similar problems when merging a multi-lane one-way road into a highway (again, this includes highways merging into highways), with traffic trying to merge across multiple lanes and potentially interrupting the flow of the highway.

Lane switching (to avoid turn-only lanes or merging traffic) has a negative effect on traffic flow on any highway with a moderate throughput of traffic. This is why junctions like this exist.

Other considerations:

  • Faster than all one-way roads, with a limit of 80 (down from 100 for highways).
    Note that this is twice the speed of two-lane roads, and thus should have about the same overall traffic capacity (at least while traffic is moving at full speed)
  • Cheap to build (30/cell; cheapest of all roads except gravel)
  • Cheap to maintain (0.32/cell; same as regular two-lane)
  • Cannot be zoned
  • No pavement for pedestrians to walk along
  • Traffic will never park on them

With all that said, personally I tend to use ramps as the entry/exit road from highways everywhere, but will often have exit ramps change into one-way two lane roads before they reach a junction, this can help the traffic to spread out as it waits at the junction and hopefully not back up down the ramp as far.


Well, the main advantage of highway ramp is its price, lower than a regular one-way road. But it term of function, it is the same as the regular one. But on the other hand, I don't think highway ramps are suitable for in-city use.

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