Moveable bridge or lift bridge can move to allow passage for boats or barges or launches through the rivers. The advantage of making this moveable bridges are the lower cost, due to the absence of high piers and long approaches. The principal disadvantage is that the traffic on the bridge must be halted when it is opened for passages. These bridge can be seen over the small river but this river is busy. It is not possible to make this bridge higher in this small river. So, it is necessary a lift or moveable bridge on this river.
There are a lot of canals in the Netherlands and that means a lot of bridges. There is also a lot of experimentation and innovation there. Drawbridges are always interesting as designers look for different ways of getting roads and bike lanes out of the way of boats. The Slauerhoffbrug is such a bridge that stands out. The bridge, located in Leeuwarden, was designed to be a fully automatic bridge with an ability to sense and adapt to its surroundings. While this technology is not for just any bridge—more traffic requires a more intelligent controller—the bridge is sensibly high-tech for its area.

You can see this bridge is not the usual lift bridge like others. Its design is completely difference. It can set in the curve on the road. It has a weight on the opposite side of the bridge that keeps balance. Actually amazing innovation!