until or unless after 2030

[terrytan]

Hello everyone,
Following sentence comes from a grammar test. Can I use unless to replace the underlined word until? Do they mean the same thing? Thanks!
Most experts agree that we are not going to have true driverless cars on our roads until after 2030.

 

[Glasguensis]

No

 

[terrytan]

Could you please explain why? I can't figure out the differences between them. I think both until and unless are okay in this context. Thanks a lot!

No

 

[Glasguensis]

Until is used when we want to indicate that something can or will change after a period of time or when something evolves after a period of time
I will watch television until 5PM
Keep stirring until the mixture is smooth

Unless is used to indicate that something can or cannot currently occur, but that this could be inversed if some condition is met.
I will go cycling tomorrow unless it rains
You can’t get in unless you’re on the list

In your example it is clearly a period of time which is in play, so only until fits.