The Department of Public Works began installing a pretty monumental piece of the city’s bike network yesterday — parking-protected bike lanes on Arapahoe and Lawrence streets.

When complete in mid-November, the bike lanes will provide a downtown route for about a mile between Auraria Campus and 24th Street, with intersection treatments that will make it safer to cross wide streets like Speer Boulevard, Broadway, and Park Avenue. The curb will be to your right and parked cars to your left. The aim is for those vehicles to protect people on bikes from motorists driving in the travel lanes.

Making the treacherous, six-legged intersection of Arapahoe, Park, and Broadway safe for bike riders to cross is a cornerstone of the design. That’s where a contra-flow bike lane at Arapahoe and Broadway will get its own crossing phase, allowing riders to cross while traffic is stopped in all directions. People on bikes will get their own signal and crossing phase at Lawrence and Speer, and at 18th and Arapahoe as well. Bright green bike boxes at the top of busier intersections will give riders a safe head start, too.

Streetsblog Denver reported on more design specifics back in August when designs became more or less official, so check those out if you want to dig deeper.

I rode both stretches of each street today. Nothing has been done to Lawrence — the old striped bike lane is still there — but there’s some progress on Arapahoe. (Be careful when you ride Arapahoe. Workers have painted the bike lane and buffer on most of the street, but drivers are still parking along the curb on some blocks.)

It’s early, but it’s pretty exciting to see the work of DPW’s bike planners, BikeDenver, and countless advocates begin to bear fruit. Streetsblog Denver will continue to cover and critique these bike lanes. In the mean time, here are a bunch of photos: