0 in switch case?

Sorry for maybe dumb question, but i have HUGE problem with one case when i have some int variable with value of 0(zero).

            switch ($starost_vozila){
                case (0):
                    switch ($podaci['tip_motora']){
                        case ("motor1"):
                            $eko_taksa = 485;
                        break;
                        case ("motor2"):
                            $eko_taksa = 243;
                        break;
                        case ("motor3"):
                            $eko_taksa = 121;
                        break;
                        case ("motor4"):
                            $eko_taksa = 194;
                        break;
                    }
                break;
                case ($starost_vozila < 6):
                    switch ($podaci['tip_motora']){
                        case ("motor1"):
                            $eko_taksa = 485;
                        break;
                        case ("motor2"):
                            $eko_taksa = 243;
                        break;
                        case ("motor3"):
                            $eko_taksa = 121;
                        break;
                        case ("motor4"):
                            $eko_taksa = 194;
                        break;
                    }
                break;
                case ($starost_vozila > 5 && $starost_vozila < 11):
                    switch ($podaci['tip_motora']){
                        case ("motor1"):
                            $eko_taksa = 667;
                        break;
                        case ("motor2"):
                            $eko_taksa = 273;
                        break;
                        case ("motor3"):
                            $eko_taksa = 136;
                        break;
                        case ("motor4"):
                            $eko_taksa = 218;
                        break;