How polarized are the two political parties on key questions about transportation policy and climate change? As you can imagine, the answer is “very.”

The senior Democrat and Republican on the Senate Environment and Public Works Committee — California’s Barbara Boxer and Oklahoma’s Jim Inhofe, respectively — each wrote an opinion this week for the Eno Center for Transportation about a proposed federal rule to require state DOTs to measure their impact on greenhouse gas emissions.

Boxer is the ranking Democratic member of the committee. Her column applauds the move to measure the climate impacts of state and regional transportation policy:

Establishment of a performance measure for carbon pollution is critically needed now. Since 1970, carbon emissions produced by the transportation sector have more than doubled, increasing at a faster rate than any other end-use sector. By requiring transportation agencies to track carbon emissions, we can evaluate whether transportation investments are effective in meeting the goal of protecting the environment.

Meanwhile, Committee Chair Inhofe challenged the legitimacy of the rule:

The goal of the laws I co-authored is to improve the safety and advance the modernization of our roads and bridges. FHWA’s proposed GHG regulation would divert the limited time and resources of States and local governments away from this goal to pursue instead the administration’s unlawful and overzealous climate agenda.

Yes, the “overzealous agenda” of transparently documenting how much carbon pollution is caused by billions of dollars of spending on transportation.

FHWA regulators will be wading through these and many other comments in the coming months as they produce a rule that may or may not require states and regional planning agencies to finally measure their impact on the climate.