Larry Jaques wrote:

Close, but no cigar, since you assumed vehicles of equal mass. If you
have a Chebby Geo meet a Suburban, it will be closer to 75mph Geo vs
25mph Suburban. The doubled mass of the heavier vehicle will keep
pushing until it shoves the Geo a wee bit more. You'd definitely
rather be an occupant in the larger, heavier vehicle.

Only if you are committed to a collision and have
no other options. Otherwise I'd prefer a agile
vehicle with good braking and cornering performance.

And that would be neither a Suburban or a Geo.