08-19-2017, 12:40 PM
(08-19-2017, 10:19 AM)danbrotherston Wrote:(08-18-2017, 10:08 PM)tomh009 Wrote: How much room does a barrier take? 20cm? Even if you couldn't get any of that space from the vehicle lane (and really taking 10 cm from there should be a non-issue) that would leave 1.3m for the protected bike lane. How much space does a protected bike lane need in order to be usable?
So it depends on what type of barrier. You might be able to fit flex posts in 20 cm, but something like a curb takes 0.5 meters. Jersey barriers take even more.
A 1.3 m bike lane might be okay in some contexts, but between two barriers on a substantial uphill grade I don't think is going to be one of them.
As for taking space from vehicle lanes, I entirely agree, but sadly the engineers are utterly opposed to doing anything other than 3.35 meter lanes, and 3.65 meter curb face lanes. It's incredibly frustrating. But sadly that is the current situation.
What’s even more ridiculous is that if we would just reduce the road to a single traffic lane in each direction over the bridge, we would have tons of space for non-motor-vehicle traffic. It wouldn’t even be a matter of making any particular tradeoffs — you could probably have both a sidewalk and a bidirectional cycle track on each side. And I don’t believe a free-running segment of road with no intersections or driveways is where we need the additional lanes — it’s at intersections or locations with significant driveway activity that additional lanes are actually useful rather than just being a waste of resources, at least at the traffic levels that I understand exist on this particular road.