Once a teacher in my high school asked a similar question:
Which is worse-a head on collision with an identical car travelling the
opposite direction with equal speed, or a collision at the same speed with
an immovable brick wall.
( I wonder how he graded the responses?)
The doubling of the speed before hitting the immovable object has several
nasty effects. The car will need to get rid of four times the kinetic
energy, and may experience twice the force.
(if the collision times are equal)