Electric vehicles already contribute more in government revenue when compared to a typical family car. They pay Stamp Duty, sometimes the luxury car tax, and GST is higher because EVs are more expensive. Every electric vehicle that replaces a combustion engine car delivers an $8,763 net benefit to the economy over a ten-year life span, including the $1370 benefit to government revenue.
In other words, not only do electric vehicle owners pay more towards road maintenance than if they bought a petrol/diesel car, but the more electric vehicles bought the more revenue would be available for governments to spend on roads. (Source: Ernst & Young, Uncovering the hidden costs and benefits from Electric Vehicles)