One of the most cost-effective policies to encourage EV adoption is an exemption from high-occupancy lane rules – a relatively inexpensive incentive that boosted sales of battery electric vehicles by 15%.

Photo of heavy traffic moving at speed on the M6 motorway in England. (Courtesy: iStock/BrianAJackson)
Heavy traffic moving at speed on the M6 motorway in England. (Courtesy: iStock/BrianAJackson)

Switching from gasoline-fuelled to electric-powered vehicles can reduce local levels of air pollution, particularly in cities with lots of traffic. It’s a swap that many countries are keen to encourage, but what’s the best way to nudge vehicle owners in this direction?

In the US alone, the years since 2008 have seen more than 400 state and local incentives to increase the adoption of plug-in-electric vehicles. In a recent study, researchers searched through the data to determine the most effective tools that policy-makers can apply.

“A rebate targeted at affordable battery electric vehicles (BEVs) combined with early investments in charging infrastructure along roadways where EVs would most need them is likely to increase EV adoption,” says Easwran Narassimhan of Tufts University, US, who carried out the analysis with Caley Johnson from the US National Renewable Energy Laboratory.

Narassimhan and Johnson’s results show that a $1000 incentive increase given as a rebate can raise EV sales by 4.8% compared with just 2.3% when the saving is provided as a tax credit. The observation tallies with earlier work, which found that incentives closer to the point of sale tended to be more attractive to potential customers than rewards that arrived later.

Early investments in infrastructure get the thumbs up from the team as public charging points are likely to incentivise early adopters, which can provide a multiplying effect on electric vehicle sales. There are other options too.

Also, there are signs that rising environmental awareness could be as strong a factor as the availability of tax incentives — especially in promoting sales of plug-in hybrid electric vehicles — at least in states with a good track record in communicating pollution issues.

With more data being added all the time, policy-makers are likely to be even better equipped in future to reduce the number of gas-guzzling vehicles on our roads. Narassimhan and Johnson are keen to expand their analysis as new figures become available.

“This includes looking more closely at demographic factors such as vehicle miles travelled per capita, environmental awareness, and unemployment,” says Narassimhan. “We’re also interested in incentives for home charging and home electric vehicle supply equipment, which intuitively should have a strong relationship since a majority of electric vehicle owners charge at home.”

Narassimhan and Johnson published their work in Environmental Research Letters (ERL).