The highways in Colorado, one of the nation’s fastest-growing states, are frequently clogged with suburban workers driving into Denver, skiers heading high into the Rocky Mountains and trucks rumbling across the Interstates.A Western frontier state with an affinity for the open road and Subaru Outbacks, Colorado’s traditional answer to traffic congestion could be summed up in two words: more asphalt.But widening highways and paving new roads often just spurs people to drive more, research shows. And as concerns grow about how tailpipe emissions are heating the planet, Colorado is among a handful of car-dominated states that are rethinking road building.In December, Colorado adopted a first-of-its-kind climate change regulation that will push transportation planners to redirect funding away from highway expansions and toward projects that cut […]