Under a fair weight tax scheme, a passenger of a fully loaded bus would pay more than a solo driver of a Hummer EV (one of the heaviest SUVs on the market).
Some data on bus weights [1]:
Transit Bus Type Passengers Curb Weight (lb) Fully‐Loaded Weight (lb)
Max Seated Max Total
2‐axle 35‐foot 27 – 40 46 – 72 15,450 – 28,510 23,360 – 39,020
2‐axle 40‐foot 35 – 44 61 – 92 20,520 – 32,520 30,600 – 44,100
2‐axle 45‐foot 44 – 46 80 – 86 30,130 – 30,450 41,480 – 42,530
3‐axle 45‐foot Double‐deck 79 – 82 116 – 122 36,560 – 37,930 54,670 – 55,850
3‐axle 60‐foot Articulated 41 – 61 89 – 123 37,920 – 49,520 55,975 – 64,690
The Hummer EV's curb weight is 9063 lbs (add 150 lbs for an average driver) and it has two axles for a loaded axle weight of 4607 lbs.A three axle articulated bus with 123 passengers has a loaded axle weight of 21,563 lbs using the data from the table above.
This means that the bus has ~4.7 times the load per axle as the SUV, so per the fourth power law, it does 488 times as much damage to the road as the SUV. Since it carries 123 people, that means that each bus passenger is doing ~4 times as much damage to the road as the SUV driver.
[1] https://onlinepubs.trb.org/onlinepubs/tcrp/docs/TCRPJ-11Task... (Table 7/Page 25)