Deemphasizing Dead-EndsNavigating Today’s Dendritic Cities

Nate WesselPhD student at the University of Toronto

nate.wessel@mail.utoronto.ca

Background

Dead-ends are frustrating.

That’s why they put signs up. ->

What’s going on here?

Map #1

- All streets are the same

Map #2

- Dead-ends are 50% transparent- Indirect streets are up to 50%

transparent

1

2

What’s going on here?

Developed technique for a bike map in a hilly suburban city ->

Problem:

- Noisy map in the absence of road hierarchy

Solution

- Clarify topology- Reduce noise- Free up visual channels

So what are dead-ends, anyway?

So what are dead-ends, anyway?

Variability by mode

Variability by mode

Research Questions

1. How many dead-ends are there?2. Where are they?3. How dependant are they on mode?4. Is this even remotely helpful??

Methods

23 urban regions selected for variety and data quality

(whole built-up region used)

OpenStreetMap -> osm2po -> PostGIS -> R

Constructed graphs for: car, bike, foot

Code on Github at https://github.com/Nate-Wessel/dead-ends

Results: How many dead-ends are there?

Results: How many dead-ends are there?

Sorted by average

Results: How many dead-ends are there?

Sorted by variance

Results: Where are they?

● Edge centroids -> KDE surface weighted by edge length

● Ratio of dead-ending segments to total

● = % dead-ends, locally

Results: Where are they?

(Cincinnati by car)

Results: Dependence on mode?

Results: Dependence on mode?

Anecdotal musings:- European cities and New Urbanism

- Dead-ends for cars, connections for people

Next Step: Does this actually work?

Need to test whether this technique actually helps people read maps

● Developing platform to test○ A->B route-finding speed○ A->B route-finding accuracy○ Does it matter where A & B are? What if they are on dead-ends?

Discussion

- Technique seems relevant to many cities- Mode specificity is an issue - Data quality issues a concern ( OSM )- Algorithm could be way smarter- Needs empirical testing

The End (for now)

Nate Wessel

University of Toronto

nate.wessel@mail.utoronto.ca