Two identical cars are driving in opposite directions at the same speed. their kinetic energies have

The equation for determining the kinetic energy of the system is,

      KE = 0.5mv²

where m is the mass, v is velocity and KE is the kinetic energy. When both objects have the same mass, and velocity but different direction, they will have the same kinetic energy. 

This is because the exponent in the velocity is squared cancelling out the effect of the sign appearing before the number.