What a Transportation Engineer Calls "Walkable"

A transportation engineer sent Charles Marohn a video to prove how walkable his "diverging diamond" overpass design is. Marohn overdubbed his not-so-flattering reply.

Previously featured on Planetizen, the "diverging diamond" is a road design strategy that eliminates left turns to supposedly increase pedestrian safety. This video shows a pedestrian's view of the design, with commentary from Marohn over the supposed "walkability":

Full Story: The diverging diamond



Snow removal?

My first thought when I saw the pedestrian "walkway" at the 5 minute mark was how much use is that going to get in the winter. Now, I'm from NY so I'm not sure how much snow MO gets, but I'm thinking not many peds are going to use it in the wintertime. The streets get plowed and where will that snow go... right into the "walkway." Not a preferred design in my opinion.

It's just as safe as an standard interchange

There's a lot of ridiculous and unfounded commentary here. In the beginning at 0:50, there is no sidewide. The sidewalk wasn't removed to create the diverging diamond interchange. This would be a challenge for a pedestrian in any circumstance. At 01:07, the video doesn't portray the undulation in the sidewalk treatment. The yellow concrete pad has patterned 3D bubbles to alert vision-impaired pedestrians. Again, this would be the same conditions for a standard interchange. The commentator is also belittling the vision-impaired by calling street traffic noise "terrifying". That is very condescending. With "weeds on one side" and traffic on the other, the commentator is identifying that this, indeed, is a sidewalk.

At 02:00 the commentator is concerned about safety for pedestrians. There is a striped buffer zone for the turn lane and a pedestrian island refuge that's some 25 feet wide. The clear striping and concrete island serves as a delineator for anyone who wants to safely cross. The red decorative brick is to provide a CLEAR and DISTINCT refuge for pedestrians that contrast with the road. The fact that there are large jersey barriers to protect pedestrians in the median is completely undermined by the commentator's discussion on the lack of pedestrian safety. I am over 4 minutes into a 10 minute video, and nothing this guy is saying holds water. Everything is "terrifying" and the "insanity" of it all is too great for the commentator. He would do well in a padded cell; that would keep him safe from this world.

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