I hate to weigh in too much on this, since I didn't even make the starting line this year, but I think cars first and cars on different days are both worse.
The roads we are racing on are public and open. I would much rather be out there the day that everyone knows the race is coming through than the day before or the day after and catch a work truck coming the other way. I'm not sure if D4SS1 used the same winding road cut into the side of a hill this year, but can you imagine what would happen? It wouldn't be good in the best case, let alone the worst.
I don't expect this will be a problem that will get solved and I would expect the race to be run the same next year, but I think they need to throw more people out of the race or not let them in in the first place. How about a race resume before you're allowed to tear up the desert with 400+hp?
Last year, Walker Evans was rumored to have buzzed a bike unsafely while on course, nerfed the pace truck and during my only interaction, sent his support crew of two raptors and a trailer up the course the wrong way while the race was hot. Thats just an example, but instead of not inviting him back, he's one of the featured drivers.
Also, how about a breathalyzer at every course in and out? You think the second half of the day no one has crushed a few tecate?
The unfortunate truth is that the best way to avoid danger from other competitors is to ride fast enough that they can't catch you.