The purpose of the median is to physically separate driving directions to prevent head-on crashes, which is especially important at driving speeds above 70 km/h (see SWOV fact sheet Sustainable Road Safety). A large number of 80 or 100 km/h roads do not have medians; they would have to be constructed .
Medians can be made safer with a shielding structure (see the question What does a safe median look like?). Medians with a rigid shielding structure can be made safer by replacing the rigid shields with flexible shields (see the question What does a safe roadside (or outer verge) look like?). Widening the median generally makes it safer. It allows a greater distance of the shielding structure to the lane, reducing the risk of a crash in the median and providing a recovery zone for a vehicle with a breakdown. It also allows space for the larger working width of the flexible shielding structure. Finally, sufficient load-bearing capacity, inspection and maintenance are also important for keeping a median safe (see the question How to make roadsides safer?).