In the case of lev checkpoints, it's a predetermined time where a script is allowed to run. You have one point of movement and you're onward. The only determining factor is when you put the command to exit the station.
As for driving, there's quite a handful of variables in play that decide things.
All the same, I find the current system engaging personally. It allows things to be dynamic in the current state while not allowing players to simply stack commands and wait. If you don't want that wait, there are alternatives. Some more risky, some more expensive, some requiring more stats/skills.
Pretty much everything in SD comes with risks/rewards, pros/cons and this happens to be one of them.
Yes traffic is supposed to be annoying, but RP should come first. And the current traffic system causes that trade off to be in favor of losing RP.
I'll be perfectly honest, I went up and down the expressways 8+ times a day at one point. When traffic was active, it actively ground any RP I wanted to have to a halt. And I quit that job, not because I didn't enjoy it, or it wasn't profitable, but because OOCly, the fact was that there would be long periods of playtimes that I couldn't RP reasonably or comfortably.
OOCly and ICly, the traffic is much too frequent, and too annoying to reasonably hope to RP anything relevant.
This along with the screen being flooded by the rooms you go through and a lack of visual feedback means that asking someone to RP during that is hard.
It doesn't make me want to RP during the pauses, it makes me shut my brain off and just get it done with... Because the pauses are too short to reasonably do anything more than type around a 10 word sentence before you move onto the next command and the next stop and go.
I'd honestly be fine with one 5-10 minute pause that automatically cleared after a set amount of time... A knot of traffic you work through... Than a game I'm playing emulating stop and go traffic as accurately as Sindome does.