海角大神

After decades as the standard taxi model in Mexico City, the Volkswagen Bug is considered 鈥渃lassic鈥� Mexico.

But it could also embody the future, according to an engineer and computer scientist duo here 听鈥� with a key adjustment.

Take the 2002 white VW Bug parked in the gravel lot alongside Alto Rendimiento Automotriz, 脕lvaro de la Paz鈥檚 car shop. An extension cord runs from a connection by the front wheel well听to a household outlet. The engine has been replaced with an electric motor held up by handcrafted supports, and the back window looks down on rows of bright blue lithium batteries. An old VW bumper sticker is amended in black marker to read, 鈥淚t鈥檚 not a car鈥� It鈥檚 aN ELECTRIC Volkswagen.鈥�

Mr. de la Paz and his apprentice and partner, H茅ctor Ruiz Garc铆a, have been working together for the past five years to transform old, polluting cars into electric vehicles. It鈥檚 a passion project that both men hope will create lasting change in attitudes here toward driving, the environment, and personal health.

鈥淲e are making a difference,鈥� says Mr. Ruiz, who has more than 25 years of experience working in computer technology. 鈥淚t may not be on a large-scale, but we are helping people do more with less and offering real solutions to [environmental] problems.鈥�

Pollution has long been a challenge in this megalopolis of more than 20 million people. Mexico City slowly shed its reputation as one of the most polluted cities in the world by moving industry outside the metropolitan area in the 1990s, creating stricter emissions requirements, and expanding public transportation and bike paths. The city now has more than 90 miles of dedicated bike lanes and in 2012 opened the 12th^听 line of one of the most traveled metro systems in North America. Other cities around the globe adapted some of its programming, like Hoy No Circula, a program that bans cars from driving certain days of the week in an effort to decrease emissions.听

But about 200,000 new cars hit the road here each year, according to the city government. And the old clunkers that still circulate are some of the biggest culprits for emitting dangerous pollutants. Last spring, when Mexico City experienced an 鈥渆xtraordinary increase鈥� in ozone concentration, the highest levels of pollution the city had seen since 2005, the driving bans increased, keeping some cars off the road for multiple days a week.

It may not have helped. A recent study by economist Lucas Davis, an associate professor at the Haas School of Business at the University of California, Berkeley, found that Mexico鈥檚 driving ban, despite its popularity with policymakers, doesn鈥檛 in fact work in lowering emissions. Drivers find ways around the regulations by borrowing cars or taking taxis.

The study鈥檚 results underscore the value of citizen-led efforts like those of de la Paz and Ruiz.听

鈥淭he government needs to resolve these problems, but they can鈥檛 do it alone,鈥� says de la Paz. 鈥淭hey need citizens to be active and involved.鈥�

And it鈥檚 not just de la Paz and Ruiz. Other burgeoning programs are gaining a following 鈥� even if only on a small scale 鈥� for their attention to environmental impact. There鈥檚 an electric scooter company, modeled after popular city bike share programs, that鈥檚 popular among young urban professionals, and an online app that incentivizes bike riding in Mexico City by offering 鈥減oints鈥� that can be redeemed at local restaurants and shops, like Starbucks. Local activists are also encouraging the expansion of Mexico City鈥檚 bus rapid transit system beyond the heart of the city.

A week that makes a difference

It takes de la Paz and Ruiz about one week to change an old car into an electric vehicle. In a small concrete room in the back of the workshop, shelves are lined with batteries, converters, and custom-built chargers and metal accessories to accommodate the weight of different electric motors. The pair has transformed roughly 20 cars over the past five years, first connecting with each other in 2012 via another electric-car fanatic in Sonora state. De la Paz specializes in the mechanics and electricity; Ruiz, in customer service and buying. They are each other鈥檚 apprentices.

De la Paz first started experimenting with electric cars about 10 years ago, when he wanted one of his own. He purchased two small electric trucks, typically used in warehouses, and reverse-engineered the technology to understand how the motors worked. The men have since traveled to workshops in the United States, and import the electric motors they use in the cars 鈥� once even trying to fly with a motor as carry-on baggage. Ruiz was subjected to extra screening when officials mistook the contraption for a bomb. 听

Their passion for getting more electric cars on Mexican roads is palpable. Ruiz rattles off stats on electric car speeds and emissions, and quickly offers up the keys to his personal vehicle for a test drive. De la Paz tears up when he muses on about the responsibility he feels in his work. He explains how each project is like a puzzle, a satisfying challenge in figuring out how to create a vehicle that is safe, both for the family entrusting him to do the work and for the bystanders who might benefit from cleaner cars.

The men charge $6,000 per car, a sizable price tag but an investment they believe pays off quickly, largely via savings on gas. The price of gas jumped 20 percent on Jan. 1 this year, leading to nationwide protests over the increased cost of driving and associated costs of food and other consumer products. The men believe there鈥檚 far more benefit in targeting used cars over buying new electric vehicles from a dealership.

鈥淎 striking thing about air quality is that a large fraction of total emissions come from a very small number of vehicles,鈥� says Mr. Davis, who published the report on the shortcomings of Mexico鈥檚 driving ban program. 鈥淚f you鈥檙e driving one of these high-emitting cars, you鈥檙e imposing a real cost in terms of health on fellow citizens.鈥澨�

鈥淚 think policy makers are desperate for some kind of solution to [this] massive problem,鈥� of pollution, Davis says. Programs that ban driving have spread to cities including Bogota, Colombia; Santiago, Chile; La Paz, Bolivia; and Delhi.

鈥淎t first, they seem reasonable. In 1989, 20 percent of cars were taken off the road [in Mexico City], so you鈥檇 think that air quality would improve by 20 percent,鈥� Davis says.听

鈥淏ut that鈥檚 not the case鈥�. If I tell you you can鈥檛 drive tomorrow, you get a ride from a friend, neighbor, or family member. Or hop in a taxi or an Uber.鈥� There鈥檚 an incentive for cars that aren鈥檛 banned to hit the road, providing transportation for those that aren鈥檛 allowed to drive that day.

Change the incentive

Ruiz and de la Paz argue that if governments gave subsidies to people to change their cars from gas to electric, instead of subsidizing the purchase of a new electric car, they鈥檇 not only help in lowering emissions, but also inject more money into the local economy by supporting initiatives like theirs.

鈥淚 don鈥檛 think you can ask for voluntary sacrifices,鈥� says Davis. 鈥淵ou need to go directly after the problem,鈥� which includes better emissions testing that isn't susceptible to corruption, gasoline or congestion taxes, and getting the oldest cars off the road.

鈥淚 want to be an example, not just talk about the issues,鈥� Ruiz says. 鈥淣ot because [electric cars are] in style, but because solutions are necessary.鈥�