There are some advantages to driving a semi in traffic:
- Lots of gears to choose from and massive torque in order to find that perfect 'idle forward' speed.
- Far more comfortable ride then a car, it's not even close.
- Radio communication with trucks ahead, so you know what's happening ahead and which lane to be in long before the cars figure this out.
- Visibility over the top of vehicles in front (except another truck, obviously).
I think the only thing better than a semi for heavy traffic might be a luxury car with adaptive cruise and a little roof-mounted drone-cam that you could launch to check out the view ahead (though this sounds like something Homer Simpson would dream up). Your own little personal traffic copter/R2D2, with a recharging dock on the roof. Someone please tell Elon Musk to make this a priority for new Teslas. It could even check out side streets in cities and find quicker routes.