The bridge is situated on the site where US paratroopers crossed the river in boats during Operation Market Garden, in an attempt to take the single bridge across the river. (I'm sure you've seen "A Bridge Too Far": they were succesfull in Nijmegen, but failed in Arnhem, over at the next river.)
The bridge is called "de Oversteek" ("the crossing"), after the operation. There was a small monument at the north side of the river where the paratroopers landed, but now there's the bridge. The bridge also has a light art installation to commemorate the 48 paratroopers who died during the crossing. The bridge has 48 pairs of streetlights, and at dusk they are turned on one-by-one from south to north, at a walking pace.
You can read more in this press release by the Dutch Embassy in the US. The opening will be attended by veterans who participated in the crossing and relatives of the paratroopers who died.
We can't go today, but tomorrow the bridge is open for cyclists and pedestrians, so we'll check it out then. Monday the bridge will be open for cars.