The state’s program to remove old polluting vehicles from the roads may soon have to be temporarily halted, officials said. The North Central Texas Council of Governments, which operates the old vehicle voucher program for the state, has received 12,000 applications for people seeking money to help replace their cars and trucks. If all the applications are approved, it would exceed the first $30 million the state has allocated for the program. The council will probably stop taking applications in a few weeks, officials said. A second phase of the program should start in September with more funding from the state. The program, which began accepting applications in December, is aimed at lower-income residents of the Dallas, Houston and Austin areas who drive vehicles that are at least 10 years old. People who meet income limits of $30,630 for an individual and $72,390 for a family of five can be eligible for $3,000 vouchers to use on new or late-model vehicles. The vehicles they purchase must cost $25,000 or less.