A bike bridge across Highway 101 isn’t a bad idea. I wouldn’t want to negotiate the Steele Lane underpass on my bike. But $20 million (as suggested in a city report)? For a bridge and approach ramps that might, conservatively, stretch a half-mile from east to west?

Even the $13 million figure presented at Tuesday’s council meeting seems excessive.

Consider some other transportation projects:

The estimated cost of the 70-mile SMART rail system is $695 million, about $9.9 million a mile.

The Highway 101 widening project from Santa Rosa to Windsor was recently completed for about $15.1 million a mile. For the 14.6 miles widened from Rohnert Park to Windsor since 2001, the cost was about $19.3 million a mile. Most expensive was the 2½-mile elevated segment from Highway 12 to Steele Lane, which cost $46 million per mile.

And a bike bridge across a six-lane highway is going to cost the equivalent of $25 million a mile? Sounds more like pro sports than public works.

See our editorial page on Thursday for more discussion of this project.

— Jim Sweeney