Hi, sorry for the delay. I will implement composite spline for the next release, that mean you will be able to enable meshes that can be part of bridges (like support and pylon, i will add this to default content for example). So bridges will be more easy to do in the next version, even if you can already make bridges. For tunnel, it is pretty easy to do, you disable auto digging on a part of the road, paint a hole where the spline passes through the landscape and fulfill with stones around the hole for good looking. Take 1 minute. I will also include a dome for example to add on the 2 lane road. I think it is a good idea for the next version to make 2 videos : how to make a bridge and how to make a tunnel 