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Comment by konspence | Hacker News Reader

Same in Vancouver, BC. The Lions Gate bridge has reversible lanes toggled by overhead signs.

https://upload.wikimedia.org/wikipedia/commons/7/7e/Lions_Ga...

The Golden Gate Bridge had that for decades, but there were too many accidents. A "zipper" barrier was considered many times, but early versions weren't strong enough to stay put if hit, or were too wide, eating up too much lane width.

Lake Shore Drive in Chicago had solid lane dividers which were raised out of the pavement hydraulically.[1] These didn't work reliably and were abandoned in the 1970s.

[1] http://historicbridges.org/illinois/lincolnpark/ccp_passe.jp...

My memory is that the Golden Gate Bridge used movable traffic cones (pylons) for decades before the current barrier system. Was there a time that lane direction was only based on overhead signage?

Pictures of the bridge show a whole range of things the Golden Gate Bridge authority tried. Solid lines for every lane. Double lines down the middle. Neon signs ("2/3/4 lanes") at each end. Traffic cones at each end to guide cars into the 2/3/4 lane arrangement. Pylons that plugged into the bridge deck. (Probably post-1986, when the bridge deck was replaced, one section at a time. and the roadway was widened by two feet.)

A "zipper" movable barrier was considered several times, but early versions were too wide or not strong enough. Finally they got one that worked.

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