1.58 Update: Physics & Collisions Changes

As we prepare the ground for the arrival of new vehicle types through upcoming content for Euro Truck Simulator 2 and American Truck Simulator such as Road Trip and Coaches, we’ve revisited and significantly refined the in-game physics simulation, including how vehicles behave, how they respond to your inputs, and how collisions and contact with the world are handled. 

To make that possible, we had to take a major look “under the hood” and revisit some of the fundamentals of how physics is simulated in our games. Some adjustments were made with these new vehicle categories in mind, often lighter, shorter, and in some cases more powerful than what our simulation was originally tuned for but many of the improvements also benefit every vehicle, including the trucks you’re already familiar with.  

The goal throughout all of this has been simple, to improve realism and responsiveness, while keeping the core truck driving experience you know and love fully recognizable, just better refined. Pavel Č, one of our programmers here at SCS Software, explained that despite the scale of the work, the goal was always to enhance what players already know and enjoy. “A lot of things under the hood changed, but we tried very hard to make sure that the core truck driving experience is still recognizable, but better,” he shared.
 

One of the first areas addressed was throttle response, which is now properly calculated from a throttle torque engine map. Combined with a more realistic level of engine resistance when you’re off the throttle, this makes coasting feel more natural and gives cruising a smoother, more believable flow.

Beyond engine response, the update also includes mechanical improvements that add extra nuance to how trucks behave on different surfaces. Wheels now camber when going off-road in a way that better reflects how a solid axle suspension behaves, and turning wheels also incorporate caster. These are subtle details, but they contribute to a more authentic feel when the terrain gets uneven or when you move away from perfectly flat roads. The audio you hear whilst driving has also been refined, with turbocharger sounds now reflecting more accurately what the engine is doing, making the overall driving feedback feel more connected.

Another change that you may notice is that the engine now revs slightly to build up torque before pulling away. Pavel goes onto explain “This helps the truck feel a little more alive when moving off from a stop. However, that improvement also brought challenges in specific scenarios, particularly when starting on inclines, so a hill start assistant was introduced to support those situations and make them feel more reliable.” 

We've also spent time improving how the game feels for keyboard users, where the throttle control can often be an all-or-nothing experience. "We really wanted to improve the way the throttle behaves with keyboard controls", Pavel said, which led to the development of the double throttle control system. Holding the throttle key now applies partial throttle, allowing for smooth, controlled acceleration and making it easier to settle into a relaxed cruising pace. When you do need more power for situations like overtaking, or climbing a hill, you can "double tap" the throttle key for full acceleration potential. Once you've finished your overtake, or topped the summit of the hill, simply release the throttle key, and press it again to return to a partial throttle state.

This feature will be turned off by default, meaning vehicles will continue to deliver their full performance as usual. However, you’ll be able to enable it through the settings if you’d like to try a smoother, more relaxed throttle response on a keyboard. Once the 1.58 update arrives, we recommend giving it a go. It may be an option you find especially useful not only for trucking, but also for driving in the future.

Preparing the physics simulation for the arrival of smaller vehicles wasn’t simply a matter of tweaking a few values. It required careful attention to a system that has been developed and tuned around trucks for many years, and expanding that simulation beyond its original design. “We had a working physics simulation for trucks that was very in-depth, but extending a simulation outside of its original bounds meant a lot of changes,” Pavel explained.

We also took the opportunity to revisit another important part of the driving experience in this upcoming update. For American Truck Simulator, we’ve adjusted the collision geometry of almost all roads, and this work has also helped improve the stability of trucks in some specific cases. One example of where you may feel the difference is when entering turning lanes at highway intersections at higher speeds, where handling can now feel more consistent and controlled. 

More technically, this comes down to how road curvature was represented in the original triangle-based collision model. As the road roll angle changes, the triangles used to form curves could create a subtle “sawtooth” profile along the center of the road, as the collision faces turned toward each other. This could reduce the friction force applied to the wheels in certain situations, impacting stability and smoothness. With the updated collision model, we now have the opportunity to create smoother road curvature directly within the collision geometry, improving wheel contact and delivering more predictable behaviour on the road.

The 1.58 update is just the beginning of a wider set of improvements we’re working towards. It marks the starting point for bigger changes we’ll be making in preparation for upcoming content, while also pushing forward the overall quality, realism, and responsiveness of the driving experience for both Euro Truck Simulator 2 and American Truck Simulator. 

As we continue working on the new vehicle types coming to our games, especially for Road Trip, we’re stepping into territory we’ve never had to simulate before. Some of these vehicles can come with levels of power and torque that push our in-game world, assets, code, and physics systems in entirely new ways. 

From the very beginning, the plan with Road Trip has never been to compete with racing or hardcore simulation games, but to offer something different, a chance to explore and experience the virtual world we've created from a fresh perspective behind the wheel of iconic vehicles, striking a balance that would keep it enjoyable even for casual players. Because of that, we may prefer to set up a vehicle's performance settings so that the player is not punished too hard for driving errors. We will make choices that fit the limited narrative of the early Road Trip packs, choices which we may revisit later, as the ambition with our Road Trip concept is to evolve it over time. We want to ensure that the driving experience remains believable, stable, and enjoyable.

Our team involved in this project wanted to share a few words with you, our #BestCommunityEver “I would like to encourage all players to try the Open Beta once it is available, and share their feedback to help with further development. Input from our community is an integral part of our daily work, and it’s thanks to you that we can keep improving.”

We hope you enjoyed reading this blog on and perhaps learned a thing or two about the development of our driving physics. If you did, be sure to leave a comment on our blog. Until next time, keep on truckin’!