General Road and Highway Discussion

[danbrotherston]

I see.  So what you are describing are what the region refers to as something like "enhanced, delayed decision point slip lane" (because drivers must slow down and nearly stop at the corner instead of being able to turn at speed) and they are preferred by regional engineers in new construction.

Yes, they are not as bad as traditional turn islands. But I disagree that these are better for peds than no slip lanes, yes, they do reduce the crossing distance, but I still don't believe drivers are looking for peds while making turns, the main goal is still to benefit drivers, why not just have a tighter turn with no slip lane.  The value here is only that drivers can turn faster.  Large trucks can easily make these turns, even far tighter turns.  They're only "better" when prioritizing cars is the assumed condition.

Well, this pedestrian would rather cross an intersection with carefully designed slip lanes. So you may want to consider that this isn’t entirely a motor vehicle enthusiast vs. pedestrian safety enthusiast issue.

Why are they called “delayed decision”? It seems to me the driver has to make a decision to use the slip lane earlier than they are forced to make that decision at a non-slip-lane intersection or at one like Weber and University which has small slip lanes.

I’m a bit confused by “The value here is only that drivers can turn faster”. With the slip lanes I favour, I don’t see how they can turn faster, because of the tight turn at the exit.

The decision the name is referring to is the decision to turn or not, i.e., they're focused on looking for traffic, that decision point is later in the ramp because the driver must slow down more. The main reason engineers now prefer these ramps over the traditional is they have fewer car collisions.

And yes, what I mean is that, instead of having any slip ramp, we could have a tighter turn radii---I believe this would be better for peds, but drivers would have to slow down more.  The slip ramps (of any kind) exist in order to allow turning traffic a few benefits, first being much wider corners without requiring to the signal poles to be moved too far back from the intersection, and second being a yield instead of a stop for drivers.