Do you think my program will work?

    analogWrite(moteur, 90);  //run the motor
    delay(500);  //wait a bit while it runs in the direction that the car was already pointing
    myservo.write(0);  //steer left (maybe right).  Will the servo have time to move before
    myservo.write(90);  //immediately steer straight ahead

Is that what you meant ?