Options are good, however very difficult to implement IMO, and still not a long term solution.
Flexible working hours is a good option, however not very practical. You need something to motivate workers and ensure they still perform and not skip out. So you make it performance based, but then you have union issues. Also how many companies trust their workers enough to do this without good incentives. Maybe use toll money to provide these incentives. Then workers who start 5-2 flexi hours will face less congestion, will have more satisfaction, and the guys who choose to pay for tolls will fund it.
I though they are using this variable signal technology as its slowly spreading and connecting the vehicles to each other and making them smarter. I agree this might improve things, but its not the ultimate solution.
Yes the trucking industry is a huge problem, however they are very powerful, and to have them change would probably entitle significant incentives. Self driving trucks would improve things for them. However they can still use the money from the tolls and provide these incentives.
These solutions you presented are a good short term solution, and would be nice to have. However without good incentive and planning forget about it. Not very practical.
Why not toll, reduce overall congestion and use the money to fund these programs and incentives you mentioned along with others. Then you can still have the option to not use the HOT because the congestion will be reduced, maybe encouraged alternative forms of commute such as bike or transit with incentives until the inevitable happens and the whole highway gets tolled. But still use the money to give back and invest in making it better for everyone, including building these free electric charging stations that are already in plans and giving back good incentives to the people who bike, walk, carpool or take transit to work.
This will ensure I can still hit up the MPs on my way back from work without SO noticing so we all win.