Landmarks of the Week

Mexico City started keeping cars off the road one weekday a week by the last digit of their plate in November 1989, after an ozone emergency, and made the rule permanent the following year. A compulsory emissions test every six months assigns each car a hologram, and that reading decides how hard the ban bites: holograms 00 and 0 drive every day, hologram 1 also rests two Saturdays a month, hologram 2 every Saturday. Saturdays were added on 5 July 2008, and when the metropolitan monitoring network pushes ozone past the contingency threshold the regional environment commission declares a 'Fase I' that pulls even exempt cars off the road. Thirty-seven years on, peer-reviewed evaluations have still not found that the air got cleaner.

A driverless elevated light rail line opened in September 2011 over 23 km between Busan's Sasang district and Gimhae, built as a private BTO concession carrying a minimum revenue guarantee. The Korea Transport Institute had forecast 176,358 riders a day at opening; 30,084 came. Busan and Gimhae covered the shortfall, and a 2017 renegotiation swapped the revenue guarantee for cost compensation running to 2041. The two cities paid 906.8 billion won between 2011 and 2025 and owe at least 1.09 trillion more. Ridership has since recovered, from 34,752 a day in 2020 to roughly 45,800 in 2024 and 2025.

The MBTA issued its first CharlieCards on 4 December 2006 and still keeps the balance on the card — the weakness MIT students were sued for describing in 2008 and Medford high-schoolers cloned again in 2023, that time with the agency's help. Its replacement, awarded to Cubic for mid-2020, took bank cards in August 2024. Commuter rail still cannot tap.

Melbourne mapped all 70,000+ street trees with individual IDs, species and health data in its Urban Forest Visual — and citizens started emailing love letters to their favourite trees instead of just fault reports. Data-driven greening with an unexpectedly human side.

In 2017 Shenzhen became the first city to fully electrify its buses — over 16,000 of them — making it one of the largest zero-emission bus operations anywhere. The taxis came later: 99 percent of the city's 21,609 cabs were electric by the end of 2019. The switch rested less on new battery technology than on procurement and a charging backbone built alongside it — about one charging outlet for every three buses.

Since 17 February 2003, drivers entering central London during charging hours pay a daily fee, enforced by ANPR camera rings — a scheme introduced under Mayor Ken Livingstone. The charge rose from £15 to £18 in January 2026, with EV exemptions replaced by a smaller Cleaner Vehicle Discount.

Cable cars integrated into the metro network connected Medellín's informal hillside barrios to the city — the mobility backbone of one of the world's most-cited urban transformations. Six Metrocable lines operate today.