They could make the trucks safer.  I remember when Don Young voted against the double-hulled oil tankers. The cost to the oil companies seem to upset him more than harm to our environment. He hasn't changed. Nor have the drill, baby, drill sycophants. 
You might want to check out how many oil spills we have with pipelines. it's not as low as you seem to think. 
I'm wondering why Bismarck got to vote against that pipeline but the Native Americans weren't allowed.