WASHINGTON (AP) — The Obama administration sent a four-year, $302 billion transportation plan to Congress on Tuesday, hoping to jump-start a national debate on how to repair and replace the nation’s aging infrastructure while accommodating the needs of a growing population.

Action is urgently needed because the federal Highway Trust Fund is expected to run dry by late August, said Transportation Secretary Anthony Foxx. Unless Congress acts to shore up the fund, transportation aid to states will be held up and workers laid off at construction sites across the country, he said.