Yeah, we do. The heavy vehicles, pavement pounders, from bbig SUVs up to trucks, pay more since they burn more fuel. It wouldn't be necessary to track vehicles to get their mileage, either. They read the odometer at inspection time, don't they?
Still, collecting data on vehicle location and speed systemwide could be used in planning for the transportation network, new roads, road maintenance, that kind of thing instead of hiring traffic counters to sit and count vehicles.
Sure, RightWhale, and all the traffic cameras that have been put up by TexasDOT here were to be used to enhance traffic flow on IH35. Even if that really was their plan and it did generate lotsa data and "jobs", it didn't cure traffic and it cost just the same.