The importance of "Thrust Angle"

Thrust angle means the direction of vehicle's goes and it is fully dictated only by "Thrust Angle". But, steering changes the direction of the vehicle, how come? Yes, steering position is so controlled by a driver as the vehicle goes straight on a straight and flat road. The direction of front wheels total vector meets with that of rear wheels.
The thrust angle value is the same as front vector direction in broadly speaking.
Suppose, the driver in a vehicle with thrust angle should adjust the discrepancy all the time and the discrepancy causes circular movement according with the value of discrepancy, this is a Physical fact and truth, no room to cut in for any argument. Imagine again here,   very slight steering turn causes change of direction immediately, then how about forklift machinery, the same phenomena happens with rear wheel steering construction. When we go back with reverse gear selection, it is the same. Anyway, rear wheel should be fixed straight ahead with Zero Thrust Angle.
Though European Traffic Safety Standard stipulate the discrepant value as plus minus 10 minutes angle value, in case of driving with plus value in Right-hand traffic, it's very dangerous to drive such a vehicle. Probably, all the  driver must have experienced being attack by sleep, sleeping in a moment while driving, vehicle goes left side leading to head to head collision. Contraly, left-hand traffic such as UK and JP minus thrust angle is fatal at all. Sleeping with eye opening phenomena happens! Sleeping driver easily permits circular movement according to the thrust angle that the vehicle has innately.
Establishment of "Zero Thrust" is indispensable to drive a vehicle not only comfortably but to do safely.
This why I insist on thrust angle and put an emphasis on it.