> Which means 40% more road maintenance.

Nope. You've overlooked two things, one possibly minor and one major.

The minor one is that road maintenance is not just due to the need to repair damage caused by vehicles. Roads are also damaged by things as daily and seasonal temperature variation, UV from sunlight, oxygen, erosion and soil instability, and others.

An increase in damage from vehicles would might shorten the intervals between needed maintenance, but would not be a simple X% more vehicle damage means X% more maintenance.

The major one is that ICE cars need gas. Let's imagine a city where everyone drives an ICE and then switches to an EV and math this. To make things as comparable as possible let's say all the ICE cars were Hyundai Kona SELs, and they all switch to the Hyundai Kona Electric SEL.

The ICE Kona SEL weighs 3240 pounds and gets 28 mpg. The Kona Electric SEL is 3759 pounds, which is 16% more, so would be 80% more damage. Let's use the amount of damage caused by the ICE driving 1 mile as our unit of damage, so the EV causes 1.8 damage per mile.

Let's say that gas is delivered to the city's gas stations by a 5000 gallon tanker truck. The gas is loaded onto the tankers at a distribution center that is 5 miles from the city. It arrives at the distribution center by rail.

A 5000 gallon tanker will weigh somewhere in the 10000-15000 pound range when empty. 5000 gallons of gas is about 30000 pounds, so when the tanker leaves the distribution center it will weigh 40000-45000 points. Let's go with the low number. That's 12.346 as much as an ICE Kona SEL weighs, so that tanker will do 23000 units of road damager per mile. That's ~116000 units of road damage on the 5 mile trip to the city. As it goes around unloading the damage per mile goes down to 90 units per mile when the tanker is empty.

When that 5000 gallons of gas is later sold to the ICE Kona SEL drivers that will result in 140000 miles of driving and so 140000 units of damage.

If everyone switched to Kona Electric SEL that same 140000 miles would result in 252000 units of road damage, which is 112000 units more but it would also eliminate the need for 5000 gallons of gasoline delivery, saving 116000 units of road damage from the tanker. (Actually more because I'm ignoring the tanker damage once it gets to the first gas station and starts deliveries).

These numbers are going to depend a lot on what ICE and EV you compare, and how far the gas travels by tanker, but the above numbers illustrate that you definitely need to take into account the reduced need for gas delivery when estimating what a switch to EVs will do to the roads.