The silence is deafening within the Democratic primary for governor on the need to build and improve roads in Colorado after 20 years of neglect.  The Democratic contestants, U.S. Sen. Michael Bennet and Attorney General Phil Weiser, talk about liberal touchstones such as mass transit and bike lanes that few Coloradans find practical to use.   Try to find their solutions to deteriorating roads and highways, and it is as if those problems don’t exist.  iStock Not only do roads and highways not exist in the Democratic debate, legislative Democrats try to take credit for highway projects that their elected leaders from years ago actually opposed.  Republican Gov. Bill Owens, who served from 1999 to 2007, was the last governor who prioritized, built, and improved Colorado’s roads and highways.…