# Information measures and cognitive limits in multilayer navigation

Riccardo Gallotti points me to this interesting working paper in arXiv:

Information measures and cognitive limits in multilayer navigation

Cities and their transportation systems become increasingly complex and multimodal as they grow, and it is natural to wonder if it is possible to quantitatively characterize our difficulty to navigate in them and whether such navigation exceeds our cognitive limits. A transition between different searching strategies for navigating in metropolitan maps has been observed for large, complex metropolitan networks. This evidence suggests the existence of another limit associated to the cognitive overload and caused by large amounts of information to process. In this light, we analyzed the world’s 15 largest metropolitan networks and estimated the information limit for determining a trip in a transportation system to be on the order of 8 bits. Similar to the “Dunbar number,” which represents a limit to the size of an individual’s friendship circle, our cognitive limit suggests that maps should not consist of more than about 250 connections points to be easily readable. We also show that including connections with other transportation modes dramatically increases the information needed to navigate in multilayer transportation networks: in large cities such as New York, Paris, and Tokyo, more than 80% of trips are above the 8-bit limit. Multimodal transportation systems in large cities have thus already exceeded human cognitive limits and consequently the traditional view of navigation in cities has to be revised substantially.

My take is this greatly supports things like Grid networks and network simplification (see the work of Jarrett Walker). This looked at rail. Think about buses. In a few years, people will just let their apps navigate them, and human cognition limits may fall off the chart.

# MnPASS pricing algorithm to become a continuous function.

A reporter at the Star Tribune writes: The Drive: MnDOT to tweak MnPass pricing

The Minnesota Department of Transportation charges motorists driving alone anywhere from 25 cents to $8 during peak periods to use the special lanes that are otherwise reserved for carpools of two or more people, buses and motorcycles. But just how much a solo driver is charged is determined by an old complex algorithm operated by an outside vendor. It assesses real-time traffic conditions in the MnPass and the free lanes every 3 minutes and sets the price accordingly. Sometimes that leads to wild price spikes. That’s about to change. MnDOT has been working with the University of Minnesota Traffic Observatory to develop a new algorithm that will be run in-house and should better set tolls and control how fast prices rise or fall. It’s expected to be in operation by the end of December, said MnDOT freeway engineer Brian Kary. I am very happy to see this. Many drivers use the prices posted on overhead signs to judge congestion levels downstream and decide whether to enter the HOT lanes. A sudden burst in traffic can send the MnPass lane price soaring and discourage drivers from entering the HOT lanes, which then become under used. Conversely, MnPass lanes become overcrowded when the price drops too low, thus decreasing the lanes’ efficiency. Well, actually, when the price spikes, it attracts people, probably because they are using it as a signal of congestion ahead. As this very same reporter in this very same column reported on previously. Our paper on this phenomenon: The article continues: How much is too much? Chicos said$3 is about the point when she would think twice about entering the toll lanes. For others, the cutoff seems to be about \$5. Anything above that and drivers are less likely to use the lanes, according to MnDOT research.

Dense rush-hour traffic, a lane-blocking crash or a snowstorm that paralyzes traffic has the ability to instantly send tolls skyrocketing or drop just as fast.

HOT lane pricing has been about as bumpy as the pavement on I-394 was before MnDOT smoothed it out this summer. With the new algorithm, which Kary describes as a tweak to the old one, drivers should less rapid fluctuation as conditions change. The goal is to get more people in the HOT lanes, maximize their use and improve overall traffic flow.

“The old algorithm had a lot of price spikes that weren’t justified, probably because of its complexity,” Kary said. “The continuous pricing algorithm should smooth price transitions.”

More on continuous pricing algorithms in the report: MnPASS Modeling and Pricing Algorithm Enhancement. It is excellent to see research translated into practice.

# How the World Beats Traffic | Ecofiscal Commission

I am on this recording of a Google Hangout, Just chillin’ with some folks talking road pricing.

Streamed live on Nov 2, 2015
Congestion is the bane of urban life in Canada, as it is elsewhere in the world. Too many people driving too many cars at the same place at the same time—that’s congestion. The Commission’s first OnAir Google Hangout will be a virtual panel discussion with international experts on how cities are using congestion pricing to combat gridlock. Chris Ragan, chair, will host and moderate the event.
Moderator:

Chris Ragan
McGill University, Department of Economics

International Experts:

Eric Jaffe
New York bureau chief, CityLab

David Levinson
Professor, Department of Civil, Environmental, and Geo- Engineering, University of Minnesota

Lauren Mattern
City Planner, Los Angeles, California
Former Analyst, San Francisco Municipal Transportation Agency

Sam Schwartz
CEO, Sam Schwartz Engineering
Former NYC Traffic Commissioner

Gunnar Söderholm