Denmark built the bike lanes – but people are still getting in cars.

Geospatial research, news, FOSS, visualization, tools

npj Urban Sustainability - Space for people, not cars: a large-scale visual choice experiment on urban street redesigns

List of Transport related people on Mastodon

We introduce the \emph{Safe Bicycle Network with Bounded Detours} (\emph{SBNBD}) problem, motivated by upgrading rural road networks for bicycle traffic. Given an undirected graph with safe and unsafe edges, edge lengths, upgrade costs, terminal pairs, a budget, and a detour factor $α$, the task is to upgrade unsafe edges so that each terminal pair is connected by a safe path of length at most $α$ times its shortest-path distance in the original network. We study SBNBD from a parameterized perspective. We prove strong NP-hardness on restricted graph classes, including planar graphs of treewidth two, graphs with feedback vertex set number one, and graphs of maximum degree three, and complement these lower bounds with polynomial-time algorithms for trees and graphs of maximum degree two. We show fixed-parameter tractability for the number of unsafe edges and prove matching SETH-based lower bounds, a polynomial-kernel lower bound, and W-hardness for natural parameters. Our main structural result maps any instance to an equivalent instance with $O(\mathrm{fes}+p)$ vertices and edges, where $\mathrm{fes}$ is the feedback edge number and $p$ the number of terminal pairs; this yields fixed-parameter tractability for $\mathrm{fes}+p$. Finally, we evaluate ILP-based algorithms on OpenStreetMap road networks for small German municipalities and their surroundings. The instances have small treewidth upper bounds and moderate feedback edge structure. Preprocessing based on the $\mathrm{fes}+p$ reduction and tree-decomposition-based cut generation both improve exact solving, especially on harder instances. Experiments with different detour factors show that increasing $α$ can reduce the upgraded-edge length, revealing trade-offs between upgrade cost and allowed relative detours. Overall, structural graph parameters provide a useful algorithmic lens for safe bicycle-network design.

Why there’s no European Google? par Ploum - Lionel Dricot.

A new book posits that physical space, rather than policy, is the primary constraint for urban transport. I speak to the authors to learn more.

Transportation Secretary Sean Duffy announced Tuesday that his department would redirect $1.73 billion in Biden-era grants away from establishing “DEI bike lanes” to build roads and bridges instead. So, what exactly is a “DEI bike lane?” The Daily Wire pointed to former Transportation Secretary Pete Buttigieg’s claim that a series of 2021 grants funding bike lanes would serve to “improve infrastructure, strengthen supply chains, make us safer, advance equity, and combat climate change.” Upon hearing “equity,” President Donald Trump’s goons can’t help but get triggered into attacking any federal spending that won’t benefit them directly. In reality, those Biden-era grants directed funds to build a new transit center in North Carolina, replace bridges in New Mexico, extend streets in New Hampshire, install traffic lights and crosswalks in Missouri, and install bike lanes in Seattle, among other projects. Now the financial status of these projects is unclear. The Daily Wire also complained that when the Biden administration announced the availability of $1.5 billion in grants in 2023, applicants were encouraged “to consider how their projects can address climate change, ensure racial equity, and remove barriers to opportunity.” Those funds were already awarded to dozens of projects across the country—not just bike lanes—in both rural and urban areas. The Trump administration has made extensive efforts to root out federal programs addressing racial discrimination. Now it seems that to even have considered racial inequality is grounds for losing millions of dollars. “America is fortunate to have a Builder in the White House who knows America is only as great as our infrastructure,” Duffy told The Daily Wire. “That’s why this Department is investing in repairing critical roads and bridges that connect Americans to job opportunities, port infrastructure that bolsters our national security, and aviation and transit projects that move American families.” But American families benefit from the presence of bike lanes, even if they don’t use them. Even the federal government acknowledges that bicycle lanes make roads a lot safer. “To make bicycling safer and more comfortable for most types of bicyclists, State and local agencies should consider installing bicycle lanes,” said a statement from the Federal Highway Administration. “Providing bicycle facilities can mitigate or prevent interactions, conflicts, and crashes between bicyclists and motor vehicles, and create a network of safer roadways for bicycling.” Rather, it seems likely that the Trump administration has chosen to zero in on bike lanes because they may be associated with urban areas that are led by Democrats and home to minority groups. The move is simultaneously a blow to the diverse communities in American cities and a cheap culture-war win over the liberal urbanites. At the same time, the policy is in line with Trump’s efforts to boost gas-powered vehicles. But American families will suffer from a lack of bike lanes too, especially with gas prices remaining high—and likely to stay that way.