It's odd, I drive a fair bit & I've not heard any radio interference from other cars at all to 648. If I'm overtaking a Fridge truck, I get a brief bit of electrical noise - I expect they have an inverter to power the Fridge side of things.
It would be interesting, to find if there is a way of suppressing EV car interference - thoughts?
BTW, I have a 1.8 Petrol Vectra Still going strong at 16 years old, & nearly 200,000 miles on the clock !