I also was very surprised, when server started with no any vehicles.
OK, I shutted down server, restored db from the backup, double checked and was sure, that there was filled vehicle table.
Now, I started server again, but when I connected to server as player and checked vehicle table again:
mysql> SELECT * FROM vehicle;
Empty set (0.00 sec)
So, bug can be somewhere in Exile module. Before I administrated Epoch and were no such surprises. Yea, sometimes vehicles exploded, but clear (redis) tables - never