Most Americans have no idea that Congress is a step closer to making a dangerous decision: allowing bigger, heavier tractor-trailers onto the roads they use every day.

The proposal sounds technical, which is exactly why it may escape public notice. But buried in the highway bill in Congress is a plan to let states raise the federal truck-weight limit on interstate highways from 80,000 pounds to 91,000 pounds. That is an extra 5.5 tons per truck.