Spiritual Meaning:
Crashing actually suggests breaking up and signifies, therefore, a difficulty in remaining whole or complete in a spiritual sense.

Psychological / Emotional Perspective:
A crash as in a collision suggests a traumatic occurrence, perhaps by not paying attention to detail. Crashing out would suggest losing a hold on reality.

Everyday Material Aspects:
A computer crashing in dreams signifies a loss of information or power.  To hear a crash is to be alerted to an imminent problem.

Also consult the entries for Car and Journey.