Indiana's Wireless EV Charging Road: How the Pilot Works

Originally published 2021-09-05.

In July 2021, the Indiana Department of Transportation (INDOT) announced a research project with Purdue University and the German company Magment to develop a stretch of highway that could charge electric vehicles wirelessly while they drive. The plan was to embed coils in the pavement, using Magment's magnetisable concrete, so that vehicles fitted with a receiver could pick up power on the move. It was presented as a staged trial, starting in the laboratory, with a quarter-mile test road to follow if the early phases worked.

Headlines at the time described it as a road that would charge cars "for free". The project never promised that. It was a research pilot, and questions about who would pay for the electricity and how drivers would be billed were still open.

How a wireless charging road works

The idea, known as dynamic wireless power transfer, is a larger version of the charging pad that tops up a phone. Coils buried under the road surface carry an alternating current and create a magnetic field. A second coil mounted under the vehicle sits in that field and converts it back into electricity for the battery or motor.

Two practical problems shape every design. The first is the air gap between the road and the car, which is much larger than the few millimetres between a phone and its pad, so some energy is lost. The second is alignment: a vehicle drifting across the lane collects less power than one centred over the coils.

Magment's approach was to mix recycled ferrite particles into concrete. Ferrite guides magnetic fields, so the company argued that its material could improve transfer while avoiding some of the cost of copper-heavy systems, which mattered in 2021 when copper prices hit record highs. Magment's chief executive, Mauricio Esguerra, called the project "a real step forward towards the future of dynamic wireless charging". The company also claimed transmission efficiency of up to 95 per cent at standard road-building costs, a figure that came from the firm and had not been independently tested on a public road.

What Indiana actually planned

The work sat within ASPIRE (Advancing Sustainability through Powered Infrastructure for Roadway Electrification), a research centre funded by the US National Science Foundation, in which Purdue takes part. The plan had three phases:

1. Research and lab testing of the pavement design and Magment's material, starting in July 2021.
2. Further development and testing, which Purdue hoped to complete together with phase one by the end of 2022.
3. A quarter-mile test road at a site still to be chosen, hoped for some time in 2023, with the aim of charging heavy trucks at high power.

INDOT said it was particularly interested in corridors with heavy commercial truck traffic, because long-haul freight is hard to electrify with batteries alone. If the tests succeeded, the agency said real-world installation could take several more years, and the partners promised to publish their findings.

Local reporting later described a quarter-mile test bed on the northbound right lane of US 231 in West Lafayette, near Purdue's campus, with lab work carried out at INDOT's research facility first. By 2024 the project had moved towards building an electrified test strip aimed at heavy trucks, and Purdue engineers were studying whether such roads could make electric freight cheaper for businesses.

Indiana was not alone

Several countries have tested ways of charging vehicles on the move, with different technologies:

• Italy: the "Arena del Futuro" near Brescia, built by the Israeli company Electreon with motorway operator Brebemi, Stellantis and Iveco, opened in December 2021. It is a 1.05 km test track, not a 70 km road as some 2021 articles claimed. A passenger car on it went from 22 to 48 per cent charge while driving, and an electric bus ran for three days without stopping to charge.
• Detroit, USA: Electreon and the Michigan Department of Transportation opened a quarter-mile wireless charging section near Michigan Central in November 2023, funded with about 5.9 million dollars.
• Germany: rather than buried coils, the eHighway trials used overhead lines that trucks connect to with a pantograph, including a 10 km section of the A5 motorway south of Frankfurt opened in 2019.
• Sweden: the Swedish Transport Administration studied electric roads for a decade, but cancelled its first permanent procurement in 2023 when bids exceeded the budget.
• South Korea: KAIST's OLEV buses in Gumi used road-embedded charging from 2013, though several lines later closed because of ageing equipment.

The challenges that remain

Experts were cautious from the start. Mark Kosowski of the Electric Power Research Institute worried that the system could lead to roads being "torn up and needing constant maintenance". Beyond repairs, engineers point to a list of open problems:

• Cost: installing coils and power electronics under every lane is far more expensive than ordinary paving, so early projects focus on short, busy stretches.
• Vehicle compatibility: only cars, buses or trucks fitted with matching receivers can charge. Such receivers are not standard equipment on mass-market cars.
• Efficiency: real-world tests have often captured much less energy than lab figures suggest. A German bus trial in 2023 recorded about 64 per cent.
• Weather and utilities: water, salt, freezing and the need to reach pipes and cables under the road all complicate long-term use.
• Billing: charging on the move needs a way to identify each vehicle and charge for power, and responsibility between road agencies and utilities is still unclear.

Myth check: free charging and the end of range anxiety

Was charging going to be free? No such promise was made. The Indiana project was about proving the technology, and any future public system would need a way to pay for the electricity.

Would every electric car work on it? No. Vehicles need a compatible receiver, which today means special test vehicles or buses.

Will it replace charging stations? Unlikely in the near term. The most realistic use is on short, heavily used stretches such as bus routes, ports, depots and freight corridors, where vehicles follow predictable paths and can use smaller batteries.

Is it just a gimmick? Not necessarily. For heavy trucks and buses, topping up on the move could cut battery size, weight and cost. That is why the research continues, even though large networks remain years away.

Where this leaves electric road charging

Indiana's 2021 announcement was an early step in a slow process, not the opening of a finished road. Its value lies in the testing data it was designed to produce, which can show whether magnetised concrete is durable and efficient enough for American highways.

For most drivers, plug-in charging at home, at work and at fast-charging stations will remain the normal way to power an electric car for years. Wireless roads are more likely to arrive first where trucks and buses can benefit, with any expansion depending on results like those from Indiana, Italy and Michigan.

Sources: Utility Dive: Indiana DOT, Purdue developing wireless EV charging for highways; Good News Network: German firm looks to build wireless EV charging road in Indiana; WLFI: INDOT, Purdue want to electrify US 231; Electreon: Arena del Futuro, Italy; Wikipedia: Electric road.