DENVER -- Take a drive along Interstate 70 during rush hour and you'll see a lot of brake lights, but what you don't see, Shawn Chandler walks under every day to get to work.
"It's really bad underneath there, " said Chandler. "You can see where the concrete is like chipping away."
He's talking about the old I-70 bridge over Harlan Street.
It's one of the top five most traveled, structurally deficient bridges in the state, according to a new report by the American Road and Transportation Builders Association.
"A good chunk of our bridges in Colorado are structurally deficient and that's scary," said Christian Reece, executive director of Club 20.
"People always ask me what keeps me up at night; challenges with bridges keep me up at night," said Shailen Bhatt, executive director of CDOT.
The crumbling I-70 viaduct bridge, overpass at US 6 and Wadsworth St., and I-70 bridge at Havana -- which CDOT has already replaced -- also made the list.
"You don't have to think too far to Minneapolis and the US I-35 bridge that came down," said Bhatt.
Bhatt said FASTER funding has helped pay for some bridge improvements, but not enough.
"Now I've got Quebec, I've got Montview, I've got Harlan - I've got all these other bridges built in the 60s on I-70 that need to be replaced," he said.
Bhatt also said any voter approved increase in the gas or sales tax would help pay for other much needed repairs. He points to the bridge at Floyd Hill as the second worst bridge in the state.
"If we get this finding, I promise you we'll fix Floyd Hill, we'll get another lane coming out of Denver and we can have it built in five years," said Bhatt.
Voters could be asked to approve a tax increase this November.