Fifty-one billion miles.

That's more than 100,000 round trips to the moon.

The next time someone tells you that Colorado doesn't need to worry about highway capacity — because, you know, millennials don't drive as much as previous generations or because of some other reason that sounds plausible on the surface — remember that figure.

Last year motorists in this state very likely drove about 51 billion miles.

Officials don't know for sure because estimates haven't been finalized, but they do know that motorists in Colorado drove about 49 billion miles in 2014 — which was itself a significant jump from 2013. And as of October, the Federal Highway Administration estimated that vehicle miles traveled in Western states was growing at a robust 4.7 percent for the year.

Since Colorado's population has actually been rising faster than some Western states, motorists here probably equaled that percentage at least. Hence the ballpark estimate of 51 billion.

We emphasize this growth of vehicle miles traveled because the environmental statement for the plan to widen parts of Interstate 70 through north Denver entered its period of public review this month, and it continues through March 2. And once again some interest groups are saying Colorado doesn't need more highway capacity — not even on roads such as I-70 in north Denver that haven't been improved in half a century.


Now, it's absolutely true that you can't build your way out of congestion in metro Denver or indeed on much of the Front Range because of constraints of land and money. Smart transportation policy must be based on other strategies. But that doesn't mean when the opportunity presents itself to add capacity to a major highway that has to be reconstructed anyway — in this case because of a structurally deficient viaduct — that the state shouldn't seize the opportunity to address capacity.

That's especially true in a metro area that continues to add residents at a fast clip.

The Colorado Department of Transportation's goal for I-70 involves widening it from three to five lanes in each direction between Brighton Boulevard and Colorado Boulevard, and tolling the new lanes. But since it doesn't have money for four new lanes, it initially plans to build just one new managed lane each way.

That not only makes sense, it's absolutely essential.