This post originally appeared on Orphan Road.

Let’s forget about fancy-schmancy infrastructure projects for a minute here on OR and focus on sidewalks:

Forty percent of Seattle streets lack full sidewalks on both sides of the road — totaling 650 miles, the city estimates — but installing them is a staggering expense of about $2 million per mile. It’s not just the cost of the pavement: When a curb is built, it changes the flow of surface water, triggering legal requirements for drainage systems, which in turn can involve buying adjacent property. Many cities can build them only as part of a major street-paving project.

650 miles @ $2M a mile, that’s $1.3B to do the whole city, including drainage systems!

A few weeks ago, city staff estimated it would cost Seattle up to $4.5 billion to add sidewalks for all Seattle streets — and this doesn’t include the cost of putting in drainage systems.

Oh. Well, okay, so it’s $4.5B, plus the drainage systems. Well, we better get cracking!

The Seattle Department of Transportation plans to spend about $1 million annually on sidewalk installation, out of the Bridging the Gap levy approved by voters last year.

At that rate, it’ll only take … 450 years to do the whole city. D’oh!

All joking aside, I do hope that the city continues its innovative natural drainage program when it finally does get around to installing these sidewalks.